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Sample records for ghrelin receptor genes

  1. Hepatic changes in metabolic gene expression in old ghrelin and ghrelin receptor knockout mice

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    Ghrelin knockout (GKO) and ghrelin receptor (growth hormone secretagogue receptor) knockout (GHSRKO) mice exhibit enhanced insulin sensitivity, but the mechanism is unclear. Insulin sensitivity declines with age and is inversely associated with accumulation of lipid in liver, a key glucoregulatory ...

  2. Association studies on ghrelin and ghrelin receptor gene polymorphisms with obesity.

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    Gueorguiev, Maria; Lecoeur, Cécile; Meyre, David; Benzinou, Michael; Mein, Charles A; Hinney, Anke; Vatin, Vincent; Weill, Jacques; Heude, Barbara; Hebebrand, Johannes; Grossman, Ashley B; Korbonits, Márta; Froguel, Philippe

    2009-04-01

    Ghrelin exerts a stimulatory effect on appetite and regulates energy homeostasis. Ghrelin gene variants have been shown to be associated with metabolic traits, although there is evidence suggesting linkage and association with obesity and the ghrelin receptor (GHSR). We hypothesized that these genes are good candidates for susceptibility to obesity. Direct sequencing identified 12 ghrelin single-nucleotide polymorphisms (SNPs) and 8 GHSR SNPs. The 10 common SNPs were genotyped in 1,275 obese subjects and in 1,059 subjects from a general population cohort of European origin. In the obesity case-control study, the GHSR SNP rs572169 was found to be associated with obesity (P = 0.007 in additive model, P = 0.001 in dominant model, odds ratio (OR) 1.73, 95% confidence interval (1.23-2.44)). The ghrelin variant, g.A265T (rs4684677), showed an association with obesity (P = 0.009, BMI adjusted for age and sex) in obese families. The ghrelin variant, g.A-604G (rs27647), showed an association with insulin levels at 2-h post-oral glucose tolerance test (OGTT) (P = 0.009) in obese families. We found an association between the eating behavior "overeating" and the GHSR SNP rs2232169 (P = 0.02) in obese subjects. However, none of these associations remained significant when corrected for multiple comparisons. Replication of the nominal associations with obesity could not be confirmed in a German genome-wide association (GWA) study for rs4684677 and rs572169 polymorphisms. Our data suggest that common polymorphisms in ghrelin and its receptor genes are not major contributors to the development of polygenic obesity, although common variants may alter body weight and eating behavior and contribute to insulin resistance, in particular in the context of early-onset obesity.

  3. Association study of ghrelin receptor gene polymorphisms in rheumatoid arthritis.

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    Robledo, G; Rueda, B; Gonzalez-Gay, M A; Fernández, B; Lamas, J R; Balsa, A; Pascual-Salcedo, D; García, A; Raya, E; Martín, J

    2010-01-01

    Ghrelin is a newly characterised growth hormone (GH) releasing peptide widely distributed that may play an important role in the regulation of metabolic balance in inflammatory diseases such as rheumatoid arthritis (RA) by decreasing the pro-inflammatory Th1 responses. In this study we investigated the possible contribution of several polymorphisms in the functional Ghrelin receptor to RA susceptibility. A screening of 3 single nucleotide polymorphisms (SNPs) was performed in a total of 950 RA patients and 990 healthy controls of Spanish Caucasian origin. Genotyping of all 3 SNPs was performed by real-time polymerase chain reaction technology, using the TaqMan 5'-allele discrimination assay. We observed no statistically significant deviation between RA patients and controls for the GHSR SNPs analysed. In addition, we performed a haplotype analysis that did not reveal an association with RA susceptibility. The stratification analysis for the presence of shared epitope (SE), rheumatoid factor (RF) or antibodies anti cyclic citrullinated peptide (anti-CCP) did not detect significant association of the GHSR polymorphisms with RA. These findings suggest that the GHSR gene polymorphisms do not appear to play a major role in RA genetic predisposition in our population.

  4. The role of ghrelin and ghrelin-receptor gene variants and promoter activity in type 2 diabetes.

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    Garcia, Edwin A; King, Peter; Sidhu, Kally; Ohgusu, Hideko; Walley, Andrew; Lecoeur, Cecile; Gueorguiev, Maria; Khalaf, Sahira; Davies, Derek; Grossman, Ashley B; Kojima, Masayasu; Petersenn, Stephan; Froguel, Phillipe; Korbonits, Márta

    2009-08-01

    Ghrelin and its receptor play an important role in glucose metabolism and energy homeostasis, and therefore they are functional candidates for genes carrying susceptibility alleles for type 2 diabetes. We assessed common genetic variation of the ghrelin (GHRL; five single nucleotide polymorphisms (SNP)) and the ghrelin-receptor (GHSR) genes (four SNPs) in 610 Caucasian patients with type 2 diabetes and 820 controls. In addition, promoter reporter assays were conducted to model the regulatory regions of both genes. Neither GHRL nor GHSR gene SNPs were associated with type 2 diabetes. One of the ghrelin haplotypes showed a marginal protective role in type 2 diabetes. We observed profound differences in the regulation of the GHRL gene according to promoter sequence variants. There are three different GHRL promoter haplotypes represented in the studied cohort causing up to 45% difference in the level of gene expression, while the promoter region of GHSR gene is primarily represented by a single haplotype. The GHRL and GHSR gene variants are not associated with type 2 diabetes, although GHRL promoter variants have significantly different activities.

  5. The Association of Polymorphisms in Leptin/Leptin Receptor Genes and Ghrelin/Ghrelin Receptor Genes With Overweight/Obesity and the Related Metabolic Disturbances: A Review.

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    Ghalandari, Hamid; Hosseini-Esfahani, Firoozeh; Mirmiran, Parvin

    2015-07-01

    Leptin and ghrelin are two important appetite and energy balance-regulating peptides. Common polymorphisms in the genes coding these peptides and their related receptors are shown to be associated with body weight, different markers of obesity and metabolic abnormalities. This review article aims to investigate the association of common polymorphisms of these genes with overweight/obesity and the metabolic disturbances related to it. The keywords leptin, ghrelin, polymorphism, single-nucleotide polymorphism (SNP), obesity, overweight, Body Mass Index, metabolic syndrome, and type 2 diabetes mellitus (T2DM) (MeSH headings) were used to search in the following databases: Pubmed, Sciencedirect (Elsevier), and Google scholar. Overall, 24 case-control studies, relevant to our topic, met the criteria and were included in the review. The most prevalent leptin/leptin receptor genes (LEP/LEPR) and ghrelin/ghrelin receptor genes (GHRL/GHSR) single nucleotide polymorphisms studied were LEP G-2548A, LEPR Q223R, and Leu72Met, respectively. Nine studies of the 17 studies on LEP/LEPR, and three studies of the seven studies on GHRL/GHSR showed significant relationships. In general, our study suggests that the association between LEP/LEPR and GHRL/GHSR with overweight/obesity and the related metabolic disturbances is inconclusive. These results may be due to unidentified gene-environment interactions. More investigations are needed to further clarify this association.

  6. Associations between ghrelin and ghrelin receptor polymorphisms and cancer in Caucasian populations: a meta-analysis

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    Pabalan, Noel A; Seim, Inge; Jarjanazi, Hamdi; Chopin, Lisa K

    2014-01-01

    Background There is growing evidence that the ghrelin axis, including ghrelin (GHRL) and its receptor, the growth hormone secretagogue receptor (GHSR), play a role in cancer progression. Ghrelin gene and ghrelin receptor gene polymorphisms have been reported to have a range of effects in cancer, from increased risk, to protection from cancer, or having no association. In this study we aimed to clarify the role of ghrelin and ghrelin receptor polymorphisms in cancer by performing a meta-analys...

  7. The Ghrelin Receptor (Ghsr) Gene Polymorphism in Indonesian Local Chicken and Crossbreed is Associated with Carcass Traits

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    Khaerunnisa, Isyana; Jakaria, Jakaria; Arief, Irma Isnafia; Budiman, Cahyo; Sumantri, Cece

    2017-01-01

    Ghrelin receptor (GHSR) gene is candidate gene for growth performance in chicken by modulating growth hormone release from the pituitary by binding to its ligand of ghrelin. Ghrelin gene, or growth hormone secretagogue (GHS) gene, is well known as feed intake and energy homeostasis regulator in mammals and birds. The objectives of this study were to identify the polymorphism of the T1857C GHSR locus in Indonesian local chicken and to evaluate its effects on carcass traits. The gene polymorphi...

  8. The Association of Polymorphisms in Leptin/Leptin Receptor Genes and Ghrelin/Ghrelin Receptor Genes With Overweight/Obesity and the Related Metabolic Disturbances: A Review

    OpenAIRE

    Ghalandari; Hosseini-Esfahani; Mirmiran

    2015-01-01

    Context Leptin and ghrelin are two important appetite and energy balance-regulating peptides. Common polymorphisms in the genes coding these peptides and their related receptors are shown to be associated with body weight, different markers of obesity and metabolic abnormalities. This review article aims to investigate the association of common polymorphisms of these genes with overweight/obesity and the metabolic disturbances related to it. E...

  9. Association of ghrelin receptor gene polymorphism with bulimia nervosa in a Japanese population.

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    Miyasaka, K; Hosoya, H; Sekime, A; Ohta, M; Amono, H; Matsushita, S; Suzuki, K; Higuchi, S; Funakoshi, A

    2006-09-01

    Eating disorders (EDs) have a highly heterogeneous etiology and multiple genetic factors might contribute to their pathogenesis. Ghrelin, a novel growth hormone-releasing peptide, enhances appetite and increases food intake, and human ghrelin plasma levels are inversely correlated with body mass index. In the present study, we examined the 171T/C polymorphism of the ghrelin receptor (growth hormone secretagogue receptor, GHSR) gene in patients diagnosed with EDs, because the subjects having ghrelin gene polymorphism (Leu72Met) was not detected in a Japanese population, previously. In addition, beta3 adrenergic receptor gene polymorphism (Try64Arg) and cholecystokinin (CCK)-A receptor (R) gene polymorphism (-81A/G, -128G/T), which are both associated with obesity, were investigated. The subjects consisted of 228 Japanese patients with EDs [96 anorexia nervosa (AN), 116 bulimia nervosa (BN) and 16 not otherwise specified (NOS)]. The age- and gender-matched control group consisted of 284 unrelated Japanese subjects. The frequency of the CC type of the GHSR gene was significantly higher in BN subjects than in control subjects (chi(2) = 4.47, p = 0.035, odds ratio = 2.05, Bonferroni correction: p = 0.070), while the frequency in AN subjects was not different from that in controls. The distribution of neither beta3 adrenergic receptor gene nor CCK-AR polymorphism differed between EDs and control subjects. Therefore, the CC type of GHSR gene polymorphism (171T/C) is a risk factor for BN, but not for AN.

  10. Expression of the gene encoding the ghrelin receptor in rats selected for differential alcohol preference.

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    Landgren, Sara; Engel, Jörgen A; Hyytiä, Petri; Zetterberg, Henrik; Blennow, Kaj; Jerlhag, Elisabet

    2011-08-01

    The mechanisms involved in alcohol use disorder, a chronic relapsing brain disorder, are complex and involve various signalling systems in the brain. Recently, the orexigenic peptide ghrelin was shown to be required for alcohol-induced reward, an effect mediated via ghrelin receptors, GHS-R1A, at the level of the cholinergic-dopaminergic reward link. Moreover, ghrelin increases and GHR-R1A antagonists reduce moderate alcohol consumption in mice, and a single nucleotide polymorphism in the GHS-R1A gene has been associated with high alcohol consumption in humans. Therefore, GHS-R1A gene expression and alcohol intake were investigated in high, AA (Alko, Alcohol), versus low, ANA (Alko, Non-Alcohol), alcohol consuming rats as well as in Wistar rats. In the AA and ANA rats plasma ghrelin levels were also measured. GHS-R1A gene expression was increased in AA compared to ANA rats in nucleus accumbens, ventral tegmental area, amygdala, prefrontal cortex and hippocampus. A similar trend was observed in the ventral tegmental area of Wistar rats consuming high amounts of alcohol. Furthermore, the AA rats had significantly smaller reduction of plasma ghrelin levels over time, after several weeks of alcohol exposure, than had the ANA rats. The present study provides further evidence for that the ghrelin signalling system, in particular at the level of the mesocortocolimbic dopamine system, is involved in alcohol consumption, and thus possibly contributes to alcohol use disorder. Therefore the GHS-R1A may constitute a novel candidate for development of new treatment strategies for alcohol dependence. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Association Analysis of the Leptin and Ghrelin Receptor Gene Polymorphism in the Human with BMI

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    Zuzana Lieskovská

    2011-05-01

    Full Text Available The aim of this work was identification of Leptin and Ghrelin receptor gene polymorphism in the population. Leptin is a product of obese (ob gene expression that plays a role in energy metabolism and body weight. The human leptin gene is located in the 17 chromosome. The restriction site is located at the position 2549 bp (C→A. Ghrelin, a peptide hormone predominantly produced by the stomach, was isolated as the endogenous ligand for the growth hormone secretagogue receptor. Ghrelin is a potent stimulator of growth hormone (GH secretion and is the only circulatory hormone known to potently enhance feeding and weight gain and to regulate energy homeostasis following central and systemic administration. Therapeutic intervention with ghrelin in catabolic situations may induce a combination of enhanced food intake, increased gastric emptying and nutrient storage, coupled with an increase in GH thereby linking nutrient partitioning with growth and repair processes. The present study included 35 human samples. The average value of BMI was estimate on 24.45. The size of amplified PCR product is 242bp. Subsequently we used the specific restriction enzyme HhaI and length of fragments is 181+61 bp in the homozygote CC, 242+181+61 bp in the heterozygote AC and 242 bp in the homozygote AA. The restriction site is located at the position 171T/C. Examination of the polymorphism of the GHSR gene was accomplished used PCR-RFLP method. We used amplified the 593 bp product, which was subsequently digested with restriction enzyme LweI and length of fragmetnts is 593 bp in the homozygote TT, 593+567+26 bp in the heterozygote TC and 593+26 bp in the homozygote CC. We assume that this mutation has connection with human obesity level.

  12. Molecular Characterization of the Ghrelin and Ghrelin Receptor Genes and Effects on Fat Deposition in Chicken and Duck

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    Q. Nie

    2009-01-01

    Full Text Available Ghrelin (GHRL and its receptor (GHSR are involved in various bioactivities. In this study, the complete cDNA and 5′ flanking region of the duck GHRL (dGHRL gene and a 3717 bp fragment of the duck GHSR (dGHSR gene were obtained. A total of 19, 8, 43, and 48 SNPs identified in 2751, 1358, 3671, and 3567 bp of the chicken GHRL (cGHRL, chicken GHSR (cGHSR, dGHRL, and dGHSR genes, respectively. Both cGHRL and dGHRL were expressed predominantly in the proventriculus, whereas the highest mRNA levels of cGHSR and dGHSR were detected in the breast muscle and pituitary. Association analysis showed that C-2047G, A-2355C, and A-2220C of the cGHRL gene were significantly associated with abdominal fat weight (AFW; P=.01, crude protein content of leg muscle (CPCLM; P=.02, and CPCLM (P=.0009, respectively. C-1459T of the cGHSR gene was also significantly associated with CPCLM (P=.0004. C-729T of dGHRL and A3427T of dGHSR were both significantly associated with subcutaneous fat thickness (SFT; P=.04. It was indicated by this study that the GHRL and GHSR genes were related to fat deposition in both chicken and duck.

  13. Polymorphisms in genes encoding leptin, ghrelin and their receptors in German multiple sclerosis patients.

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    Rey, Linda K; Wieczorek, Stefan; Akkad, Denis A; Linker, Ralf A; Chan, Andrew; Hoffjan, Sabine

    2011-01-01

    Multiple sclerosis (MS) is a neuro-inflammatory, autoimmune disease influenced by environmental and polygenic components. There is growing evidence that the peptide hormone leptin, known to regulate energy homeostasis, as well as its antagonist ghrelin play an important role in inflammatory processes in autoimmune diseases, including MS. Recently, single nucleotide polymorphisms (SNPs) in the genes encoding leptin, ghrelin and their receptors were evaluated, amongst others, in Wegener's granulomatosis and Churg-Strauss syndrome. The Lys656Asn SNP in the LEPR gene showed a significant but contrasting association with these vasculitides. We therefore aimed at investigating these polymorphisms in a German MS case-control cohort. Twelve SNPs in the LEP, LEPR, GHRL and GHSR genes were genotyped in 776 MS patients and 878 control subjects. We found an association of a haplotype in the GHSR gene with MS that could not be replicated in a second cohort. Otherwise, no significant differences in allele or genotype frequencies were observed between patients and controls in this particular cohort. Thus, the present results do not support the hypothesis that genetic variation in the leptin/ghrelin system contributes substantially to the pathogenesis of MS. However, a modest effect of GHSR variation cannot be ruled out and needs to be further evaluated in future studies. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Epistatic interaction between haplotypes of the ghrelin ligand and receptor genes influence susceptibility to myocardial infarction and coronary artery disease.

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    Baessler, Andrea; Fischer, Marcus; Mayer, Bjoern; Koehler, Martina; Wiedmann, Silke; Stark, Klaus; Doering, Angela; Erdmann, Jeanette; Riegger, Guenter; Schunkert, Heribert; Kwitek, Anne E; Hengstenberg, Christian

    2007-04-15

    Data from both experimental models and humans provide evidence that ghrelin and its receptor, the growth hormone secretagogue receptor (ghrelin receptor, GHSR), possess a variety of cardiovascular effects. Thus, we hypothesized that genetic variants within the ghrelin system (ligand ghrelin and its receptor GHSR) are associated with susceptibility to myocardial infarction (MI) and coronary artery disease (CAD). Seven single nucleotide polymorphisms (SNPs) covering the GHSR region as well as eight SNPs across the ghrelin gene (GHRL) region were genotyped in index MI patients (864 Caucasians, 'index MI cases') from the German MI family study and in matched controls without evidence of CAD (864 Caucasians, 'controls', MONICA Augsburg). In addition, siblings of these MI patients with documented severe CAD (826 'affected sibs') were matched likewise with controls (n = 826 Caucasian 'controls') and used for verification. The effect of interactions between genetic variants of both genes of the ghrelin system was explored by conditional classification tree models. We found association of several GHSR SNPs with MI [best SNP odds ratio (OR) 1.7 (1.2-2.5); P = 0.002] using a recessive model. Moreover, we identified a common GHSR haplotype which significantly increases the risk for MI [multivariate adjusted OR for homozygous carriers 1.6 (1.1-2.5) and CAD OR 1.6 (1.1-2.5)]. In contrast, no relationship between genetic variants and the disease could be revealed for GHRL. However, the increase in MI/CAD frequency related to the susceptible GHSR haplotype was abolished when it coincided with a common GHRL haplotype. Multivariate adjustments as well as permutation-based methods conveyed the same results. These data are the first to demonstrate an association of SNPs and haplotypes within important genes of the ghrelin system and the susceptibility to MI, whereas association with MI/CAD could be identified for genetic variants across GHSR, no relationship could be revealed for GHRL

  15. Expression of the ghrelin receptor gene in neurons of the medulla oblongata of the rat.

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    Bron, Romke; Yin, Lei; Russo, Domenico; Furness, John B

    2013-08-15

    There is ambiguity concerning the distribution of neurons that express the ghrelin receptor (GHSR) in the medulla oblongata. In the current study we used a sensitive nonradioactive method to investigate GHSR mRNA distribution by in situ hybridization. Strong expression of the GHSR gene was confirmed in neurons of the facial nucleus (FacN, 7), the dorsal vagal complex (DVC), and the semicompact (but not compact) nucleus ambiguus (AmbSC and AmbC). In addition, expression of GHSR was found in other regions, where it had not been described before. GHSR-positive neurons were observed in the gustatory rostral nucleus tractus solitarius and in areas involved in vestibulo-ocular processing (such as the medial vestibular nucleus and the nucleus abducens). GHSR expression was also noted in ventral areas associated with cardiorespiratory control, including the gigantocellular reticular nucleus, the lateral paragigantocellular nucleus, the rostral and caudal ventrolateral medulla, the (pre)-Bötzinger complex, and the rostral and caudal ventrolateral respiratory group. However, GHSR-positive neurons in ventrolateral areas did not express markers for cardiovascular presympathetic vasomotor neurons, respiratory propriobulbar rhythmogenic neurons, or sensory interneurons. GHSR-positive cells were intermingled with catecholamine neurons in the dorsal vagal complex but these populations did not overlap. Thus, the ghrelin receptor occurs in the medulla oblongata in 1) second-order sensory neurons processing gustatory, vestibulo-ocular, and visceral sensation; 2) cholinergic somatomotor neurons of the FacN and autonomic preganglionic neurons of the DMNX and AmbSC; 3) cardiovascular neurons in the DVC, Gi, and LPGi; 4) neurons of as yet unknown function in the ventrolateral medulla. Copyright © 2013 Wiley Periodicals, Inc., A Wiley Company.

  16. Leptin receptor and ghrelin genes polymorphisms in relation to the metabolism of lipids

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    Anna Trakovická

    2015-10-01

    Full Text Available The aim of this work was to analyse genetic polymorphisms in genes encoding leptin receptor (LEPR and ghrelin (GHR as genetic markers of metabolic disorders in human nutrition. Genomic DNA was obtained from in total 84 human blood samples. Effect of analysed genetic markers was evaluated for three biochemical parameters: total cholesterol, HDL and LDL cholesterol. The PCR-RFLP method was used for identification of SNPs in LEPR (Gln223Arg and GHR (171T/C genes. In analysed population prevalence of heterozygous LEPRAG (47.62% and GHRCT (40.48% genotypes was observed. Frequency of LEPRA and LEPRB alleles were 0.55 and 0.45, respectively. Similar the GHRC allele had only slight predominance than GHRT allele (0.54/0.46. In population was found higher level of observed heterozygosity across loci (0.44. For both SNPs was found high effective allele number (1.98 which was also transferred to the median level of polymorphic information content (0.37. Association analysis of LEPR and GHR genotypes effect on selected biochemical parameters was performed using GLM procedure. Significant association was found only for levels of LDL cholesterol (P<0.01. Our study shows that both genes are involved in nutritional status and therefore can be considered as candidate genes of lipids metabolism disorders and obesity.

  17. Polymorphisms of genes coding for ghrelin and its receptor in relation to colorectal cancer risk: a two-step gene-wide case-control study.

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    Campa, Daniele; Pardini, Barbara; Naccarati, Alessio; Vodickova, Ludmila; Novotny, Jan; Steinke, Verena; Rahner, Nils; Holinski-Feder, Elke; Morak, Monika; Schackert, Hans K; Görgens, Heike; Kötting, Judith; Betz, Beate; Kloor, Matthias; Engel, Christoph; Büttner, Reinhard; Propping, Peter; Försti, Asta; Hemminki, Kari; Barale, Roberto; Vodicka, Pavel; Canzian, Federico

    2010-09-28

    Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor (GHSR), has two major functions: the stimulation of the growth hormone production and the stimulation of food intake. Accumulating evidence also indicates a role of ghrelin in cancer development. We conducted a case-control study to examine the association of common genetic variants in the genes coding for ghrelin (GHRL) and its receptor (GHSR) with colorectal cancer risk. Pairwise tagging was used to select the 11 polymorphisms included in the study. The selected polymorphisms were genotyped in 680 cases and 593 controls from the Czech Republic. We found two SNPs associated with lower risk of colorectal cancer, namely SNPs rs27647 and rs35683. We replicated the two hits, in additional 569 cases and 726 controls from Germany. A joint analysis of the two populations indicated that the T allele of rs27647 SNP exerted a protective borderline effect (Ptrend = 0.004).

  18. Thermogenic characterization of ghrelin receptor null mice

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    Ghrelin is the only known circulating orexigenic hormone that increases food intake and promotes adiposity, and these physiological functions of ghrelin are mediated through its receptor growth hormone secretagogue receptor (GHS-R). Ghrelin/GHS-R signaling plays a crucial role in energy homeostasis....

  19. Physiological roles revealed by ghrelin and ghrelin receptor deficient mice

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    Ghrelin is a hormone made in the stomach and known primarily for its growth hormone releasing and orexigenic properties. Nevertheless, ghrelin through its receptor, the GHS-R1a, has been shown to exert many roles including regulation of glucose homeostasis, memory & learning, food addiction and neur...

  20. Associations between ghrelin and ghrelin receptor polymorphisms and cancer in Caucasian populations: a meta-analysis.

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    Pabalan, Noel A; Seim, Inge; Jarjanazi, Hamdi; Chopin, Lisa K

    2014-11-07

    There is growing evidence that the ghrelin axis, including ghrelin (GHRL) and its receptor, the growth hormone secretagogue receptor (GHSR), play a role in cancer progression. Ghrelin gene and ghrelin receptor gene polymorphisms have been reported to have a range of effects in cancer, from increased risk, to protection from cancer, or having no association. In this study we aimed to clarify the role of ghrelin and ghrelin receptor polymorphisms in cancer by performing a meta-analysis of published case-control studies. In the overall analysis, homozygous and recessive associations indicated that the minor alleles of rs696217 and rs2075356 GHRL polymorphisms conferred reduced cancer risk (odds ratio [OR] 0.61-0.78). The risk was unchanged for breast cancer patients when analysed separately (OR 0.73-0.83). In contrast, the rs4684677 GHRL and the rs572169 GHSR polymorphisms conferred increased breast cancer risk (OR 1.97-1.98, p = 0.08 and OR 1.42-1.43, p = 0.08, respectively). All dominant and co-dominant effects showed null effects (OR 0.96-1.05), except for the rs572169 co-dominant effect, with borderline increased risk (OR 1.08, p = 0.05). This study suggests that the rs696217 and rs2075356 ghrelin gene (GHRL) polymorphisms may protect carriers against breast cancer, and the rs4684677 GHRL and rs572169 GHSR polymorphisms may increase the risk among carriers. In addition, larger studies are required to confirm these findings.

  1. Ghrelin receptor controls obesity by fat burning

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    Emerging evidence show that brown fat in the body produces heat to burn energy, thus prompting weight loss. Ghrelin is the only known hormone which increases appetite and promotes weight gain. We have reported that mice that lack the receptor which mediates the functions of ghrelin are lean. Our fu...

  2. Ghrelin and Ghrelin Receptor Modulation of Psychostimulant Action

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    Paul Jeff Wellman

    2013-09-01

    Full Text Available Ghrelin (GHR is an orexigenic gut peptide that modulates multiple homeostatic functions including gastric emptying, anxiety, stress, memory, feeding and reinforcement. GHR is known to bind and activate growth-hormone secretagogue receptors (termed GHR-Rs. Of interest to our laboratory has been the assessment of the impact of GHR modulation of the locomotor activation and reward/reinforcement properties of psychostimulants such as cocaine and nicotine. Systemic GHR infusions augment cocaine stimulated locomotion and conditioned place preference (CPP in rats, as does food restriction which elevates plasma ghrelin levels. Ghrelin enhancement of psychostimulant function may occur owing to a direct action on mesolimbic dopamine function or may reflect an indirect action of ghrelin on glucocorticoid pathways. Genomic or pharmacological ablation of GHR-Rs attenuates the acute locomotor-enhancing effects of nicotine, cocaine, amphetamine and alcohol and blunts the CPP induced by food, alcohol, amphetamine and cocaine in mice. The stimulant nicotine can induce CPP and like amphetamine and cocaine, repeated administration of nicotine induces locomotor sensitization in rats. Inactivation of ghrelin circuit function in rats by injection of a ghrelin receptor antagonist (e.g. JMV 2959 diminishes the development of nicotine-induced locomotor sensitization. These results suggest a key permissive role for GHR-R activity for the induction of locomotor sensitization to nicotine. Our finding that GHR-R null rats exhibit diminished patterns of responding for intracranial self-stimulation complements an emerging literature implicating central GHR circuits in drug reward/reinforcement. Finally, antagonism of GHR-Rs may represent a smoking cessation modality that not only blocks nicotine-induced reward but that also may limit weight gain after smoking cessation.

  3. Sequence genomic organization and expression of two channel catfish Ictalurus punctatus Ghrelin receptors

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    Two ghrelin receptor (GHS-R) genes were isolated from channel catfish tissue and a bacterial artificial chromosome (BAC) library. The two receptors were characterized by determining tissue distribution, ontogeny of receptor mRNA expression, and effects of exogenous homologous ghrelin administration ...

  4. Evidence that central pathways that mediate defecation utilize ghrelin receptors but do not require endogenous ghrelin.

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    Pustovit, Ruslan V; Callaghan, Brid; Ringuet, Mitchell T; Kerr, Nicole F; Hunne, Billie; Smyth, Ian M; Pietra, Claudio; Furness, John B

    2017-08-01

    In laboratory animals and in human, centrally penetrant ghrelin receptor agonists, given systemically or orally, cause defecation. Animal studies show that the effect is due to activation of ghrelin receptors in the spinal lumbosacral defecation centers. However, it is not known whether there is a physiological role of ghrelin or the ghrelin receptor in the control of defecation. Using immunohistochemistry and immunoassay, we detected and measured ghrelin in the stomach, but were unable to detect ghrelin by either method in the lumbosacral spinal cord, or other regions of the CNS In rats in which the thoracic spinal cord was transected 5 weeks before, the effects of a ghrelin agonist on colorectal propulsion were significantly enhanced, but defecation caused by water avoidance stress (WAS) was reduced. In knockout rats that expressed no ghrelin and in wild-type rats, WAS-induced defecation was reduced by a ghrelin receptor antagonist, to similar extents. We conclude that the ghrelin receptors of the lumbosacral defecation centers have a physiological role in the control of defecation, but that their role is not dependent on ghrelin. This implies that a transmitter other than ghrelin engages the ghrelin receptor or a ghrelin receptor complex. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  5. Hindbrain ghrelin receptor signaling is sufficient to maintain fasting glucose.

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    Michael M Scott

    Full Text Available The neuronal coordination of metabolic homeostasis requires the integration of hormonal signals with multiple interrelated central neuronal circuits to produce appropriate levels of food intake, energy expenditure and fuel availability. Ghrelin, a peripherally produced peptide hormone, circulates at high concentrations during nutrient scarcity. Ghrelin promotes food intake, an action lost in ghrelin receptor null mice and also helps maintain fasting blood glucose levels, ensuring an adequate supply of nutrients to the central nervous system. To better understand mechanisms of ghrelin action, we have examined the roles of ghrelin receptor (GHSR expression in the mouse hindbrain. Notably, selective hindbrain ghrelin receptor expression was not sufficient to restore ghrelin-stimulated food intake. In contrast, the lowered fasting blood glucose levels observed in ghrelin receptor-deficient mice were returned to wild-type levels by selective re-expression of the ghrelin receptor in the hindbrain. Our results demonstrate the distributed nature of the neurons mediating ghrelin action.

  6. Characterization of adult ghrelin and ghrelin receptor knockout mice under positive and negative energy balance

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    Ghrelin and the ghrelin receptor (GH secretagogue receptor, GHS-R) are believed to have important roles in energy homeostasis. We describe results from the first studies to be conducted in congenic (N10) adult ghrelin(-/-) and Ghsr(-/-) mice under conditions of both positive (high-fat diet) and nega...

  7. Mapping and polymorphism of bovine ghreline gene

    OpenAIRE

    Colinet, Frédéric; Eggen, André; Halleux, Caroline; Arnould, Valérie; Portetelle, Daniel; Renaville, Robert

    2006-01-01

    Bovine ghrelin, a 27-amino-acid peptide has been identified in bovine oxyntic glands of the abomasum. It is an endogenous growth hormone secretagogue. Total mRNA was extracted from abomasum and complete ghrelin mRNA was sequenced by rapid amplification of cDNA ends. The gene contains five exons and four introns with a short noncoding first exon of 17 bp similar to mouse and human ghrelin gene. Using a radiation hybrid panel, the gene was mapped to chromosome 22 near microsat...

  8. Ghrelin

    DEFF Research Database (Denmark)

    Mueller, T. D.; Nogueiras, R.; Andermann, M. L.

    2015-01-01

    Background The gastrointestinal peptide hormone ghrelin was discovered in 1999 as the endogenous ligand of the growth hormone secretagogue receptor. Increasing evidence supports more complicated and nuanced roles for the hormone, which go beyond the regulation of systemic energy metabolism. Scope...... of review In this review, we discuss the diverse biological functions of ghrelin, the regulation of its secretion, and address questions that still remain 15 years after its discovery. Major conclusions In recent years, ghrelin has been found to have a plethora of central and peripheral actions in distinct...

  9. No association of defined variability in leptin, leptin receptor, adiponectin, proopiomelanocortin and ghrelin gene with food preferences in the Czech population.

    Science.gov (United States)

    Bienertova-Vasku, Julie; Bienert, Petr; Tomandl, Josef; Forejt, Martin; Vavrina, Martin; Kudelkova, Jana; Vasku, Anna

    2008-02-01

    Previously, it has been reported that mutations in the genes encoding for adipokines may be associated with impaired food intake and may serve as potential obesity biomarkers. The aim of this study was to investigate the possible associations of defined variability in leptin, leptin receptor, adiponectin, proopiomelanocortin and ghrelin genes with food preferences in the obese and non-obese Czech population and evaluate their potential as the obesity susceptibility genes. Using PCR followed by restriction analysis, we studied 185 volunteers. Basic anthropometrical characteristics associated to obesity were measured and the food intake was monitored using a 7-day record method. In the group of obese individuals, a subset of 34 morbidly obese patients was studied for plasma leptin and soluble leptin receptor levels. None of the examined polymorphisms was associated to anthropometrical or demographic characteristics of the study subjects. The Gln223Arg polymorphism within the leptin receptor gene was significantly associated with lower plasma leptin levels (the RR genotype being more frequent in patients with lower plasma leptin levels; P = 0.001). No associations of the examined polymorphisms with food preferences was observed. Based on our results, the examined polymorphisms in the adipokine genes do not seem to be the major risk factor for obesity development in the Czech population nor significantly affect food preferences.

  10. Ghrelin

    NARCIS (Netherlands)

    T.D. Müller; R. Nogueiras; M.L. Andermann; Z.B. Andrews; S.D. Anker (Stefan); J. Argente; R.L. Batterham; S.C. Benoit; C.Y. Bowers; F. Broglio (Fabio); F.F. Casanueva; D. D'Alessio; I. Depoortere; A. Geliebter; E. Ghigo (Ezio); P.A. Cole; M. Cowley; D.E. Cummings; A. Dagher (Alain); S. Diano; S.L. Dickson; C. Dieguez (Carlos); R. Granata (Riccarda); H.J. Grill; K. Grove; K.M. Habegger; K. Heppner; M.L. Heiman; L. Holsen; B. Holst; A. Inui; J.O. Jansson; H. Kirchner; M. Korbonits; B. Laferrère; C.W. LeRoux; M. Lopez; S. Morin; M. Nakazato; R. Nass; D. Perez-Tilve; P.T. Pfluger; T.W. Schwartz; R.J. Seeley; M. Sleeman; Y. Sun (Yuxiang); L. Sussel; J. Tong; M.O. Thorner; A-J. van der Lely (Aart-Jan); L.H.T. van der Ploeg; J.M. Zigman; M. Kojima; K. Kangawa; R.G. Smith (Roy); T. Horvath; M. Tschop (Matthias)

    2015-01-01

    textabstractThe gastrointestinal peptide hormone ghrelin was discovered in 1999 as the endogenous ligand of the growth hormone secretagogue receptor. Increasing evidence supports more complicated and nuanced roles for the hormone, which go beyond the regulation of systemic energy metabolism. Scope

  11. Ghrelin

    Science.gov (United States)

    Müller, T.D.; Nogueiras, R.; Andermann, M.L.; Andrews, Z.B.; Anker, S.D.; Argente, J.; Batterham, R.L.; Benoit, S.C.; Bowers, C.Y.; Broglio, F.; Casanueva, F.F.; D'Alessio, D.; Depoortere, I.; Geliebter, A.; Ghigo, E.; Cole, P.A.; Cowley, M.; Cummings, D.E.; Dagher, A.; Diano, S.; Dickson, S.L.; Diéguez, C.; Granata, R.; Grill, H.J.; Grove, K.; Habegger, K.M.; Heppner, K.; Heiman, M.L.; Holsen, L.; Holst, B.; Inui, A.; Jansson, J.O.; Kirchner, H.; Korbonits, M.; Laferrère, B.; LeRoux, C.W.; Lopez, M.; Morin, S.; Nakazato, M.; Nass, R.; Perez-Tilve, D.; Pfluger, P.T.; Schwartz, T.W.; Seeley, R.J.; Sleeman, M.; Sun, Y.; Sussel, L.; Tong, J.; Thorner, M.O.; van der Lely, A.J.; van der Ploeg, L.H.T.; Zigman, J.M.; Kojima, M.; Kangawa, K.; Smith, R.G.; Horvath, T.; Tschöp, M.H.

    2015-01-01

    Background The gastrointestinal peptide hormone ghrelin was discovered in 1999 as the endogenous ligand of the growth hormone secretagogue receptor. Increasing evidence supports more complicated and nuanced roles for the hormone, which go beyond the regulation of systemic energy metabolism. Scope of review In this review, we discuss the diverse biological functions of ghrelin, the regulation of its secretion, and address questions that still remain 15 years after its discovery. Major conclusions In recent years, ghrelin has been found to have a plethora of central and peripheral actions in distinct areas including learning and memory, gut motility and gastric acid secretion, sleep/wake rhythm, reward seeking behavior, taste sensation and glucose metabolism. PMID:26042199

  12. Identification of neurons that express ghrelin receptors in autonomic pathways originating from the spinal cord.

    Science.gov (United States)

    Furness, John B; Cho, Hyun-Jung; Hunne, Billie; Hirayama, Haruko; Callaghan, Brid P; Lomax, Alan E; Brock, James A

    2012-06-01

    Functional studies have shown that subsets of autonomic preganglionic neurons respond to ghrelin and ghrelin mimetics and in situ hybridisation has revealed receptor gene expression in the cell bodies of some preganglionic neurons. Our present goal has been to determine which preganglionic neurons express ghrelin receptors by using mice expressing enhanced green fluorescent protein (EGFP) under the control of the promoter for the ghrelin receptor (also called growth hormone secretagogue receptor). The retrograde tracer Fast Blue was injected into target organs of reporter mice under anaesthesia to identify specific functional subsets of postganglionic sympathetic neurons. Cryo-sections were immunohistochemically stained by using anti-EGFP and antibodies to neuronal markers. EGFP was detected in nerve terminal varicosities in all sympathetic chain, prevertebral and pelvic ganglia and in the adrenal medulla. Non-varicose fibres associated with the ganglia were also immunoreactive. No postganglionic cell bodies contained EGFP. In sympathetic chain ganglia, most neurons were surrounded by EGFP-positive terminals. In the stellate ganglion, neurons with choline acetyltransferase immunoreactivity, some being sudomotor neurons, lacked surrounding ghrelin-receptor-expressing terminals, although these terminals were found around other neurons. In the superior cervical ganglion, the ghrelin receptor terminals innervated subgroups of neurons including neuropeptide Y (NPY)-immunoreactive neurons that projected to the anterior chamber of the eye. However, large NPY-negative neurons projecting to the acini of the submaxillary gland were not innervated by EGFP-positive varicosities. In the celiaco-superior mesenteric ganglion, almost all neurons were surrounded by positive terminals but the VIP-immunoreactive terminals of intestinofugal neurons were EGFP-negative. The pelvic ganglia contained groups of neurons without ghrelin receptor terminal innervation and other groups with

  13. Ghrelin receptor regulates adipose tissue inflammation in aging

    Science.gov (United States)

    Aging is commonly associated with low-grade adipose inflammation, which is closely linked to insulin resistance. Ghrelin is the only circulating orexigenic hormone which is known to increase obesity and insulin resistance. We previously reported that the expression of the ghrelin receptor, growth ho...

  14. Plasma ghrelin levels and polymorphisms of ghrelin gene in Chinese obese children and adolescents.

    Science.gov (United States)

    Zhu, J F; Liang, L; Zou, C C; Fu, J F

    2010-09-01

    To evaluate the role of fasting plasma ghrelin levels [ln(ghrelin)] and polymorphisms of ghrelin gene in Chinese obese children. Genotyping for ghrelin polymorphism was performed in 230 obese and 100 normal weight children. Among them, plasma ghrelin levels were measured in 91 obese and 23 health subjects. (1) Bivariate correlation analysis showed the ln(ghrelin) was inversely correlated with abnormality of glucose metabolism (r = -0.240, P = 0.023). Stepwise multiple regression analysis showed that abnormality of glucose metabolism was an independent determinant of plasma ghrelin levels (P = 0.023). (2) There was no difference in frequency of Leu72Met polymorphisms between obese and control groups (36.09 vs. 41.00%). Ghrelin is associated with obesity in childhood, especially associated with the glucose homeostasis. Lower ghrelin levels might be a result of obesity, but not a cause of obesity. The Leu72Met polymorphism of ghrelin gene is not associated with obesity and metabolic syndrome in Chinese children.

  15. Ghrelin gene polymorphisms in rheumatoid arthritis.

    Science.gov (United States)

    Ozgen, Metin; Koca, Suleyman Serdar; Etem, Ebru Onalan; Yuce, Huseyin; Aydin, Suleyman; Isik, Ahmet

    2011-07-01

    Ghrelin, an endogenous orexigenic peptide, has anti-inflammatory effects, down-regulates pro-inflammatory cytokines, and its altered levels are reported in various inflammatory diseases. The human preproghrelin (ghrelin/obestatin) gene shows several single nucleotide polymorphisms (SNPs) including Arg51Gln, Leu72Met, Gln90Leu, and A-501C. The aim of this study was to investigate the frequency, and clinical significance, of these four SNPs in a small cohort of Turkish patients with rheumatoid arthritis (RA). The study included 103 patients with RA and 103 healthy controls. In the RA group, disease activity and disease-related damage were assessed using the Disease Activity Score-28 (DAS-28), and the modified Larsen scoring (MLS) methods. In all the participants, genomic DNA was isolated and genotyped by polymerase chain reaction and restriction fragment length polymorphism analysis. The frequencies of ghrelin gene SNPs were 82.5 and 79.6% in the RA and control groups, respectively, and there were no significant differences in terms of genotype distributions and allele frequencies for these four SNPs between the groups. However, the A-501C SNP was found to be associated with early disease onset, and Gln90Leu SNP with less frequent rheumatoid factor positivity, in the RA group. A-501C SNP is associated with earlier onset of RA suggesting that genetic variations in the ghrelin gene may have an impact on RA. Copyright © 2010 Société française de rhumatologie. Published by Elsevier SAS. All rights reserved.

  16. Ablations of ghrelin and ghrelin receptor exhibit differential metabolic phenotypes and thermogenic capacity during aging

    Science.gov (United States)

    Obesity is a hallmark of aging in many Western societies, and is a precursor to numerous serious age-related diseases. Ghrelin ("Ghrl"), via its receptor (growth hormone secretagogue receptor, GHS-R), is shown to stimulate GH secretion and appetite. Surprisingly, our previous studies showed that "Gh...

  17. Association between ghrelin gene (Leu72Met) polymorphism and ghrelin serum level with coronary artery diseases.

    Science.gov (United States)

    Hedayatizadeh-Omran, Akbar; Rafiei, Alireza; Khajavi, Rezvan; Alizadeh-Navaei, Reza; Mokhberi, Vahid; Moradzadeh, Kambiz

    2014-02-01

    Research shows that ghrelin gene polymorphism has some association with coronary artery diseases (CAD). Due to genetic differences among nations and the high prevalence of CAD, we conducted this study to examine the possible association between the polymorphism of ghrelin gene Leu72Met and CAD among an Iranian population. This case-control study was undertaken with patients who were referred to referral heart center, in 2011, with chest pain or a positive exercise test. Patients with risk factors for heart disease or who were surgery candidates, who underwent angiography and echocardiography, were also included. DNA extractions were performed using a modified salting out method, and the ghrelin region was amplified using polymerase chain reaction. The presence of the Leu72Met polymorphism and the serum levels of ghrelin were determined using the restriction fragment length polymorphism method and the enzyme-linked immunosorbent assay, respectively. The results indicated that in CAD patients, the incidence of heart failure was significantly different between the groups with genotypes CC or AA+CA (p=0.041). Mean serum level of ghrelin in the CAD group was significantly higher than that in the control group (pghrelin genotypes and serum levels of ghrelin in both the CAD and control groups (ppolymorphism, as well as an increase in serum levels of ghrelin associated with genotype distribution such that ghrelin levels have an inverse relationship with the frequency of the CC genotype.

  18. Ghrelin

    Science.gov (United States)

    The gut hormone ghrelin was discovered in 1999. In the last 15 years, ample data have been generated on ghrelin. Bedsides its hallmark function as an appetite stimulator, ghrelin also has many other important functions. In this review, we discussed ghrelin's functions in learning and memory, gut mov...

  19. Anxiolytic-Like Effects of Increased Ghrelin Receptor Signaling in the Amygdala

    DEFF Research Database (Denmark)

    Jensen, Morten; Ratner, Cecilia; Rudenko, Olga

    2016-01-01

    BACKGROUND: Besides the well-known effects of ghrelin on adiposity and food intake regulation, the ghrelin system has been shown to regulate aspects of behavior including anxiety and stress. However, the effect of virus-mediated overexpression of the ghrelin receptor in the amygdala has...... not previously been addressed directly. METHOD: First, we examined the acute effect of peripheral ghrelin administration on anxiety- and depression-like behavior using the open field, elevated plus maze, forced swim and tail suspension tests. Next, we examined the effect of peripheral ghrelin administration...... and ghrelin receptor deficiency on stress in a familiar and social environment using the Intellicage system. Importantly, we also used a novel approach to study ghrelin receptor signaling in the brain by overexpressing the ghrelin receptor in the amygdala. We examined the effect of ghrelin receptor...

  20. Neuronal deletion of ghrelin receptor almost completely prevents diet-induced obesity

    Science.gov (United States)

    Ghrelin signaling has major effects on energy- and glucose-homeostasis, but it is unknown whether ghrelin's functions are centrally and/or peripherally mediated. The ghrelin receptor, Growth Hormone Secretagogue Receptor (GHS-R), is highly expressed in brain and detectable in some peripheral tissues...

  1. Functionally biased signalling properties of 7TM receptors - opportunities for drug development for the ghrelin receptor

    DEFF Research Database (Denmark)

    Sivertsen, B; Holliday, N; Madsen, A N

    2013-01-01

    UNLABELLED: The ghrelin receptor is a 7 transmembrane (7TM) receptor involved in a variety of physiological functions including growth hormone secretion, increased food intake and fat accumulation as well as modulation of reward and cognitive functions. Because of its important role in metabolism...... and energy expenditure, the ghrelin receptor has become an important therapeutic target for drug design and the development of anti-obesity compounds. However, none of the compounds developed so far have been approved for commercial use. Interestingly, the ghrelin receptor is able to signal through several...... review, we have described how ligands and mutations in the 7TM receptor may bias the receptors to favour either one G-protein over another or to promote G-protein independent signalling pathways rather than G-protein-dependent pathways. For the ghrelin receptor, both agonist and inverse agonists have...

  2. Polymorphisms of the ghrelin/obestatin gene and ghrelin levels in Chinese children with short stature.

    Science.gov (United States)

    Zou, Chao Chun; Huang, Ke; Liang, Li; Zhao, Zheng Yan

    2008-07-01

    To investigate the role of ghrelin and polymorphisms of ghrelin/obestatin gene in children with short stature. A total of 117 GH deficient (GHD) and 81 idiopathic short stature (ISS) children were studied. The controls consisted of 125 age and gender-matched healthy children. The Arg51Gln, Leu72Met and Gln90Leu polymorphisms were genotyped using MassArray and total plasma ghrelin was measured by radioimmunoassay. In this study, the frequency of the Arg51Gln polymorphism was very low (0% in controls and 1.0% in patients). The frequency of the Gln90Leu polymorphism was 1.6% in controls and 0.5% in patients, respectively. Higher frequencies of Leu72Met (34.4% in controls and 39.9% in patients) and Met72Met genotypes (4.0% in controls and 2.0% in patients) were found. The differences in the Arg51Gln, Leu72Met or Gln90Leu genotypes and allele frequencies between patients and controls were not significant. Also, there were no significant differences in the Leu72Met genotypes and allele frequencies between GHD and ISS subgroups. There were no significant differences in clinical characteristics and biochemistry markers (including ghrelin levels) among the different genotypes of Leu72Met. However, plasma ghrelin levels in the GHD group were significantly lower than those of controls (P = 0.001). These results suggest that ghrelin may have a role in GH secretion and controlling growth. Lower ghrelin levels, but not ghrelin/obestatin polymorphism, might contribute to GHD.

  3. Multi-species sequence comparison reveals conservation of ghrelin gene-derived splice variants encoding a truncated ghrelin peptide.

    Science.gov (United States)

    Seim, Inge; Jeffery, Penny L; Thomas, Patrick B; Walpole, Carina M; Maugham, Michelle; Fung, Jenny N T; Yap, Pei-Yi; O'Keeffe, Angela J; Lai, John; Whiteside, Eliza J; Herington, Adrian C; Chopin, Lisa K

    2016-06-01

    The peptide hormone ghrelin is a potent orexigen produced predominantly in the stomach. It has a number of other biological actions, including roles in appetite stimulation, energy balance, the stimulation of growth hormone release and the regulation of cell proliferation. Recently, several ghrelin gene splice variants have been described. Here, we attempted to identify conserved alternative splicing of the ghrelin gene by cross-species sequence comparisons. We identified a novel human exon 2-deleted variant and provide preliminary evidence that this splice variant and in1-ghrelin encode a C-terminally truncated form of the ghrelin peptide, termed minighrelin. These variants are expressed in humans and mice, demonstrating conservation of alternative splicing spanning 90 million years. Minighrelin appears to have similar actions to full-length ghrelin, as treatment with exogenous minighrelin peptide stimulates appetite and feeding in mice. Forced expression of the exon 2-deleted preproghrelin variant mirrors the effect of the canonical preproghrelin, stimulating cell proliferation and migration in the PC3 prostate cancer cell line. This is the first study to characterise an exon 2-deleted preproghrelin variant and to demonstrate sequence conservation of ghrelin gene-derived splice variants that encode a truncated ghrelin peptide. This adds further impetus for studies into the alternative splicing of the ghrelin gene and the function of novel ghrelin peptides in vertebrates.

  4. Common structural basis for constitutive activity of the ghrelin receptor family

    DEFF Research Database (Denmark)

    Holst, Birgitte; Holliday, Nicholas D; Bach, Anders

    2004-01-01

    Three members of the ghrelin receptor family were characterized in parallel: the ghrelin receptor, the neurotensin receptor 2 and the orphan receptor GPR39. In transiently transfected COS-7 and human embryonic kidney 293 cells, all three receptors displayed a high degree of ligand......-independent signaling activity. The structurally homologous motilin receptor served as a constitutively silent control; upon agonist stimulation, however, it signaled with a similar efficacy to the three related receptors. The constitutive activity of the ghrelin receptor and of neurotensin receptor 2 through the G...... demonstrated that the epitope-tagged ghrelin receptor was constitutively internalized but could be trapped at the cell surface by an inverse agonist, whereas GPR39 remained at the cell surface. Mutational analysis showed that the constitutive activity of both the ghrelin receptor and GPR39 could systematically...

  5. In Situ Localization and Rhythmic Expression of Ghrelin and ghs-r1 Ghrelin Receptor in the Brain and Gastrointestinal Tract of Goldfish (Carassius auratus.

    Directory of Open Access Journals (Sweden)

    Aída Sánchez-Bretaño

    Full Text Available Ghrelin is a gut-brain peptide hormone, which binds to the growth hormone secretagogue receptor (GHS-R to regulate a wide variety of biological processes in fish. Despite these prominent physiological roles, no studies have reported the anatomical distribution of preproghrelin transcripts using in situ hybridization in a non-mammalian vertebrate, and its mapping within the different encephalic areas remains unknown. Similarly, no information is available on the possible 24-h variations in the expression of preproghrelin and its receptor in any vertebrate species. The first aim of this study was to investigate the anatomical distribution of ghrelin and GHS-R1a ghrelin receptor subtype in brain and gastrointestinal tract of goldfish (Carassius auratus using immunohistochemistry and in situ hybridization. Our second aim was to characterize possible daily variations of preproghrelin and ghs-r1 mRNA expression in central and peripheral tissues using real-time reverse transcription-quantitative PCR. Results show ghrelin expression and immunoreactivity in the gastrointestinal tract, with the most abundant signal observed in the mucosal epithelium. These are in agreement with previous findings on mucosal cells as the primary synthesizing site of ghrelin in goldfish. Ghrelin receptor was observed mainly in the hypothalamus with low expression in telencephalon, pineal and cerebellum, and in the same gastrointestinal areas as ghrelin. Daily rhythms in mRNA expression were found for preproghrelin and ghs-r1 in hypothalamus and pituitary with the acrophase occurring at nighttime. Preproghrelin, but not ghs-r1a, displayed a similar daily expression rhythm in the gastrointestinal tract with an amplitude 3-fold higher than the rest of tissues. Together, these results described for the first time in fish the mapping of preproghrelin and ghrelin receptor ghs-r1a in brain and gastrointestinal tract of goldfish, and provide the first evidence for a daily regulation

  6. Seven transmembrane G protein-coupled receptor repertoire of gastric ghrelin cells

    DEFF Research Database (Denmark)

    Engelstoft, Maja S; Park, Won-Mee; Sakata, Ichiro

    2013-01-01

    The molecular mechanisms regulating secretion of the orexigenic-glucoregulatory hormone ghrelin remain unclear. Based on qPCR analysis of FACS-purified gastric ghrelin cells, highly expressed and enriched 7TM receptors were comprehensively identified and functionally characterized using in vitro......, ex vivo and in vivo methods. Five Gαs-coupled receptors efficiently stimulated ghrelin secretion: as expected the β1-adrenergic, the GIP and the secretin receptors but surprisingly also the composite receptor for the sensory neuropeptide CGRP and the melanocortin 4 receptor. A number of Gαi....../o-coupled receptors inhibited ghrelin secretion including somatostatin receptors SSTR1, SSTR2 and SSTR3 and unexpectedly the highly enriched lactate receptor, GPR81. Three other metabolite receptors known to be both Gαi/o- and Gαq/11-coupled all inhibited ghrelin secretion through a pertussis toxin-sensitive Gαi...

  7. Ghrelin receptor mutations--too little height and too much hunger

    DEFF Research Database (Denmark)

    Holst, Birgitte; Schwartz, Thue W

    2006-01-01

    The ghrelin receptor is known from in vitro studies to signal in the absence of the hormone ghrelin at almost 50% of its maximal capacity. But, as for many other 7-transmembrane receptors, the in vivo importance of this ligand-independent signaling has remained unclear. In this issue of the JCI......, Pantel et al. find that a natural mutation in the ghrelin receptor, Ala204Glu, which is associated with a selective loss of constitutive activity without affecting ghrelin affinity, potency, or efficacy, segregates in 2 families with the development of short stature (see the related article beginning...... on page 760). By combination of the observations from this study with those related to the phenotype of subjects carrying another natural ghrelin receptor mutation, Phe279Leu, having identical molecular-pharmacological properties, it is proposed that selective lack of ghrelin receptor constitutive...

  8. Unraveling the role of the ghrelin gene peptides in the endocrine pancreas.

    Science.gov (United States)

    Granata, Riccarda; Baragli, Alessandra; Settanni, Fabio; Scarlatti, Francesca; Ghigo, Ezio

    2010-09-01

    The ghrelin gene peptides include acylated ghrelin (AG), unacylated ghrelin (UAG), and obestatin (Ob). AG, mainly produced by the stomach, exerts its central and peripheral effects through the GH secretagogue receptor type 1a (GHS-R1a). UAG, although devoid of GHS-R1a-binding affinity, is an active peptide, sharing with AG many effects through an unknown receptor. Ob was discovered as the G-protein-coupled receptor 39 (GPR39) ligand; however, its physiological actions remain unclear. The endocrine pancreas is necessary for glucose homeostasis maintenance. AG, UAG, and Ob are expressed in both human and rodent pancreatic islets from fetal to adult life, and the pancreas is the major source of ghrelin in the perinatal period. GHS-R1a and GPR39 expression has been shown in beta-cells and islets, as well as specific binding sites for AG, UAG, and Ob. Ghrelin colocalizes with glucagon in alpha-islet cells, but is also uniquely expressed in epsilon-islet cells, suggesting a role in islet function and development. Indeed, AG, UAG, and Ob regulate insulin secretion in beta-cells and isolated islets, promote beta-cell proliferation and survival, inhibit beta-cell and human islet cell apoptosis, and modulate the expression of genes that are essential in pancreatic islet cell biology. They even induce beta-cell regeneration and prevent diabetes in streptozotocin-treated neonatal rats. The receptor(s) mediating their effects are not fully characterized, and a signaling crosstalk has been suggested. The present review summarizes the newest findings on AG, UAG, and Ob expression in pancreatic islets and the role of these peptides on beta-cell development, survival, and function.

  9. Unique interaction pattern for a functionally biased ghrelin receptor agonist

    DEFF Research Database (Denmark)

    Sivertsen, Bjørn Behrens; Lang, Manja; Frimurer, Thomas M.

    2011-01-01

    Based on the conformationally constrained D-Trp-Phe-D-Trp (wFw) core of the prototype inverse agonist [D-Arg(1),D-Phe(5),D-Trp(7,9),Leu(11)]substance P, a series of novel, small, peptide-mimetic agonists for the ghrelin receptor were generated. By using various simple, ring-constrained spacers...... connecting the D-Trp-Phe-D-Trp motif with the important C-terminal carboxyamide group, 40 nm agonism potency was obtained and also in one case (wFw-Isn-NH(2), where Isn is isonipecotic acid) ~80% efficacy. However, in contrast to all previously reported ghrelin receptor agonists, the piperidine-constrained w......Fw-Isn-NH(2) was found to be a functionally biased agonist. Thus, wFw-Isn-NH(2) mediated potent and efficacious signaling through the Ga(q) and ERK1/2 signaling pathways, but in contrast to all previous ghrelin receptor agonists it did not signal through the serum response element, conceivably the Ga(12...

  10. Ghrelin receptor regulates adipose tissue inflammation in aging.

    Science.gov (United States)

    Lin, Ligen; Lee, Jong Han; Buras, Eric D; Yu, Kaijiang; Wang, Ruitao; Smith, C Wayne; Wu, Huaizhu; Sheikh-Hamad, David; Sun, Yuxiang

    2016-01-01

    Aging is commonly associated with low-grade adipose inflammation, which is closely linked to insulin resistance. Ghrelin is the only circulating orexigenic hormone which is known to increase obesity and insulin resistance. We previously reported that the expression of the ghrelin receptor, growth hormone secretagogue receptor (GHS-R), increases in adipose tissues during aging, and old Ghsr(-/-) mice exhibit a lean and insulin-sensitive phenotype. Macrophages are major mediators of adipose tissue inflammation, which consist of pro-inflammatory M1 and anti-inflammatory M2 subtypes. Here, we show that in aged mice, GHS-R ablation promotes macrophage phenotypical shift toward anti-inflammatory M2. Old Ghsrp(-/-) mice have reduced macrophage infiltration, M1/M2 ratio, and pro-inflammatory cytokine expression in white and brown adipose tissues. We also found that peritoneal macrophages of old Ghsrp(-/-) mice produce higher norepinephrine, which is in line with increased alternatively-activated M2 macrophages. Our data further reveal that GHS-R has cell-autonomous effects in macrophages, and GHS-R antagonist suppresses lipopolysaccharide (LPS)-induced inflammatory responses in macrophages. Collectively, our studies demonstrate that ghrelin signaling has an important role in macrophage polarization and adipose tissue inflammation during aging. GHS-R antagonists may serve as a novel and effective therapeutic option for age-associated adipose tissue inflammation and insulin resistance.

  11. β1-Adrenergic receptor deficiency in ghrelin-expressing cells causes hypoglycemia in susceptible individuals

    Science.gov (United States)

    Mani, Bharath K.; Osborne-Lawrence, Sherri; Vijayaraghavan, Prasanna; Hepler, Chelsea; Zigman, Jeffrey M.

    2016-01-01

    Ghrelin is an orexigenic gastric peptide hormone secreted when caloric intake is limited. Ghrelin also regulates blood glucose, as emphasized by the hypoglycemia that is induced by caloric restriction in mouse models of deficient ghrelin signaling. Here, we hypothesized that activation of β1-adrenergic receptors (β1ARs) localized to ghrelin cells is required for caloric restriction–associated ghrelin release and the ensuing protective glucoregulatory response. In mice lacking the β1AR specifically in ghrelin-expressing cells, ghrelin secretion was markedly blunted, resulting in profound hypoglycemia and prevalent mortality upon severe caloric restriction. Replacement of ghrelin blocked the effects of caloric restriction in β1AR-deficient mice. We also determined that treating calorically restricted juvenile WT mice with beta blockers led to reduced plasma ghrelin and hypoglycemia, the latter of which is similar to the life-threatening, fasting-induced hypoglycemia observed in infants treated with beta blockers. These findings highlight the critical functions of ghrelin in preventing hypoglycemia and promoting survival during severe caloric restriction and the requirement for ghrelin cell–expressed β1ARs in these processes. Moreover, these results indicate a potential role for ghrelin in mediating beta blocker–associated hypoglycemia in susceptible individuals, such as young children. PMID:27548523

  12. Ghrelin

    Directory of Open Access Journals (Sweden)

    T.D. Müller

    2015-06-01

    Major conclusions: In recent years, ghrelin has been found to have a plethora of central and peripheral actions in distinct areas including learning and memory, gut motility and gastric acid secretion, sleep/wake rhythm, reward seeking behavior, taste sensation and glucose metabolism.

  13. An 8bp indel in exon 1 of Ghrelin gene associated with chicken growth.

    Science.gov (United States)

    Fang, Meixia; Nie, Qinghua; Luo, Chenglong; Zhang, Dexiang; Zhang, Xiquan

    2007-04-01

    Ghrelin, acts as the endogenous ligand for growth hormone secretagogues receptor (GHS-R), is a novel growth hormone (GH) releasing peptide with reported effects on food intake in chickens. In this study, an 8 bp indel polymorphism in exon 1 of the chicken Ghrelin (cGHRL) gene was genotyped in a F(2) designed full-sib population to analyze its associations with chicken growth and carcass traits. Later, mRNA level in the proventriculus was determined by real-time PCR to reveal the expression feature of cGHRL gene. Result showed that this 8 bp indel was significantly associated with body weight at the age of 28 days (BW28) and 56 days (BW56), eviscerated weight (EW) and leg muscle weight (LMW) (PGhrelin on chicken growth were indicated by this study.

  14. Clinical application of ghrelin.

    Science.gov (United States)

    Strasser, Florian

    2012-01-01

    Ghrelin as a human natural hormone is involved in fundamental regulatory processes of eating and energy balance. Ghrelin signals the nutrient availability from the gastrointestinal tract to the central nervous system, up-regulates food intake and lowers energy expenditure mainly through hypothalamic mediators acting both centrally and peripherally including the gastrointestinal tract (motility, epithelium), promotes both neuro-endocrine and inflammatory signals to increase skeletal muscle growth and decrease protein breakdown, and increases lipolysis while body fat utilization is reduced. Ghrelin does more to exert its probably sentinel role around "human energy": it influences through mainly extra-hypothalamic actions the hedonic and incentive value of food, mood and anxiety, sleep-wake regulation, learning and memory, and neurogenesis. Recently numerous ghrelin gene-derived peptides were discovered, demonstrating the complexity within the ghrelin/ghrelin receptor axis. For clinical applications, not only the natural ghrelin and its slice variants, but also several modified or artificial molecules acting at ghrelin-associated receptors were and are developed. Current clinical applications are limited to clinical studies, focusing mainly on cachexia in chronic heart failure, COPD, cancer, endstage- renal-disease or cystic fibrosis, but also on frailty in elderly, gastrointestinal motility (e.g., gastroparesis, functional dyspepsia, postoperative ileus), after curative gastrectomy, anorexia nervosa, growth hormone deficient patients, alcohol craving, sleep-wake regulation (e.g. major depression), or sympathetic nervous activity in obesity. The results of completed, preliminary studies support the clinical potential of ghrelin, ghrelin gene-derived peptides, and artificial analogues, suggesting that larger clinical trials are demanded to move ghrelin towards an available and reimbursed pharmaceutical intervention.

  15. High constitutive signaling of the ghrelin receptor--identification of a potent inverse agonist

    DEFF Research Database (Denmark)

    Holst, Birgitte; Cygankiewicz, Adam; Jensen, Tine Halkjaer

    2003-01-01

    Ghrelin is a GH-releasing peptide that also has an important role as an orexigenic hormone-stimulating food intake. By measuring inositol phosphate turnover or by using a reporter assay for transcriptional activity controlled by cAMP-responsive elements, the ghrelin receptor showed strong, ligand......-independent signaling in transfected COS-7 or human embryonic kidney 293 cells. Ghrelin and a number of the known nonpeptide GH secretagogues acted as agonists stimulating inositol phosphate turnover further. In contrast, the low potency ghrelin antagonist, [D-Arg1,D-Phe5,D-Trp7,9,Leu11]-substance P was surprisingly...... found to be a high potency (EC50 = 5.2 nm) full inverse agonist as it decreased the constitutive signaling of the ghrelin receptor down to that observed in untransfected cells. The homologous motilin receptor functioned as a negative control as it did not display any sign of constitutive activity...

  16. Ghrelin in the human myometrium

    LENUS (Irish Health Repository)

    O'Brien, Margaret

    2010-05-28

    Abstract Background Ghrelin is a 28-amino acid octanolyated peptide, synthesised primarily in the stomach. It stimulates growth hormone release, food intake and exhibits many other diverse effects. Our group have previously determined that ghrelin inhibited human contractility in vitro. The aim of this study therefore, was to investigate the expression of ghrelin, its receptor, the growth hormone secretagogue receptor type 1 (GHS-R1), ghrelin O-acyltransferase (GOAT) which catalyses ghrelin octanoylation, prohormone convertase 1\\/3 (PC1\\/3) responsible for pro-ghrelin processing, in human myometrium, during pregnancy prior to labour, during labour and in the non-pregnant state. Modulation of ghrelin and ghrelin receptor expression in cultured myometrial cells was also investigated. Methods mRNA and protein were isolated from human myometrium and the myometrial smooth muscle cell line hTERT-HM; and real-time fluorescence RT-PCR, western blotting and fluorescence microscopy performed. The effects of β-Estradiol and bacterial lipopolysaccharide (LPS) on hTERT-HM gene expression were evaluated by western blotting. Results We have reported for the first time the expression and processing of ghrelin, GHS-R1, GOAT and PC1\\/3 expression in human myometrium, and also the down-regulation of ghrelin mRNA and protein expression during labour. Furthermore, GHS-R1 protein expression significantly decreased at labour. Myometrial GOAT expression significantly increased during term non-labouring pregnancy in comparison to both non-pregnant and labouring myometrium. Mature PC1\\/3 protein expression was significantly decreased at term pregnancy and labour in comparison to non-pregnant myometrium. Ghrelin, GHS-R1, GOAT and PC1\\/3 mRNA and protein expression was also detected in the hTERT-HM cells. Ghrelin protein expression decreased upon LPS treatment in these cells while β-Estradiol treatment increased GHS-R1 expression. Conclusions Ghrelin processing occurred in the human

  17. Ghrelin in the human myometrium.

    LENUS (Irish Health Repository)

    O'Brien, Margaret

    2010-01-01

    BACKGROUND: Ghrelin is a 28-amino acid octanolyated peptide, synthesised primarily in the stomach. It stimulates growth hormone release, food intake and exhibits many other diverse effects. Our group have previously determined that ghrelin inhibited human contractility in vitro. The aim of this study therefore, was to investigate the expression of ghrelin, its receptor, the growth hormone secretagogue receptor type 1 (GHS-R1), ghrelin O-acyltransferase (GOAT) which catalyses ghrelin octanoylation, prohormone convertase 1\\/3 (PC1\\/3) responsible for pro-ghrelin processing, in human myometrium, during pregnancy prior to labour, during labour and in the non-pregnant state. Modulation of ghrelin and ghrelin receptor expression in cultured myometrial cells was also investigated. METHODS: mRNA and protein were isolated from human myometrium and the myometrial smooth muscle cell line hTERT-HM; and real-time fluorescence RT-PCR, western blotting and fluorescence microscopy performed. The effects of beta-Estradiol and bacterial lipopolysaccharide (LPS) on hTERT-HM gene expression were evaluated by western blotting. RESULTS: We have reported for the first time the expression and processing of ghrelin, GHS-R1, GOAT and PC1\\/3 expression in human myometrium, and also the down-regulation of ghrelin mRNA and protein expression during labour. Furthermore, GHS-R1 protein expression significantly decreased at labour. Myometrial GOAT expression significantly increased during term non-labouring pregnancy in comparison to both non-pregnant and labouring myometrium. Mature PC1\\/3 protein expression was significantly decreased at term pregnancy and labour in comparison to non-pregnant myometrium. Ghrelin, GHS-R1, GOAT and PC1\\/3 mRNA and protein expression was also detected in the hTERT-HM cells. Ghrelin protein expression decreased upon LPS treatment in these cells while beta-Estradiol treatment increased GHS-R1 expression. CONCLUSIONS: Ghrelin processing occurred in the human

  18. Ablation of ghrelin receptor in leptin-deficient ob/ob mice has paradoxical effects on glucose homeostasis when compared with ablation of ghrelin in ob/ob mice

    Science.gov (United States)

    The orexigenic hormone ghrelin is important in diabetes because it has an inhibitory effect on insulin secretion. Ghrelin ablation in leptin-deficient ob/ob (Ghrelin(-/-):ob/ob) mice increases insulin secretion and improves hyperglycemia. The physiologically relevant ghrelin receptor is the growth ...

  19. Ghrelin interacts with neuropeptide Y Y1 and opioid receptors to increase food reward.

    Science.gov (United States)

    Skibicka, Karolina P; Shirazi, Rozita H; Hansson, Caroline; Dickson, Suzanne L

    2012-03-01

    Ghrelin, a stomach-derived hormone, is an orexigenic peptide that was recently shown to potently increase food reward behavior. The neurochemical circuitry that links ghrelin to the mesolimbic system and food reward behavior remains unclear. Here we examined the contribution of neuropeptide Y (NPY) and opioids to ghrelin's effects on food motivation and intake. Both systems have well-established links to the mesolimbic ventral tegmental area (VTA) and reward/motivation control. NPY mediates the effect of ghrelin on food intake via activation of NPY-Y1 receptor (NPY-Y1R); their connection with respect to motivated behavior is unexplored. The role of opioids in any aspect of ghrelin's action on food-oriented behaviors is unknown. Rats were trained in a progressive ratio sucrose-induced operant schedule to measure food reward/motivation behavior. Chow intake was measured immediately after the operant test. In separate experiments, we explored the suppressive effects of a selective NPY-Y1R antagonist or opioid receptor antagonist naltrexone, injected either intracerebroventricularly or intra-VTA, on ghrelin-induced food reward behavior. The ventricular ghrelin-induced increase in sucrose-motivated behavior and chow intake were completely blocked by intracerebroventricular pretreatment with either an NPY-Y1R antagonist or naltrexone. The intra-VTA ghrelin-induced sucrose-motivated behavior was blocked only by intra-VTA naltrexone. In contrast, the intra-VTA ghrelin-stimulated chow intake was attenuated only by intra-VTA NPY-Y1 blockade. Finally, ghrelin infusion was associated with an elevated VTA μ-opioid receptor expression. Thus, we identify central NPY and opioid signaling as the necessary mediators of food intake and reward effects of ghrelin and localize these interactions to the mesolimbic VTA.

  20. Modulation of the constitutive activity of the ghrelin receptor by use of pharmacological tools and mutagenesis

    DEFF Research Database (Denmark)

    Mokrosinski, Jacek; Holst, Birgitte

    2010-01-01

    Ghrelin and its receptor are important regulators of metabolic functions, including appetite, energy expenditure, fat accumulation, and growth hormone (GH) secretion. The ghrelin receptor is characterized by an ability to signal even without any ligand present with approximately 50......% of the maximally ghrelin-induced efficacy-a feature that may have important physiological implications. The high basal signaling can be modulated either by administration of specific ligands or by engineering of mutations in the receptor structure. [D-Arg(1), D-Phe(5), D-Trp(7,9), Leu(11)]-substance P...... was the first inverse agonist to be identified for the ghrelin receptor, and this peptide has been used as a starting point for identification of the structural requirements for inverse agonist properties in the ligand. The receptor binding core motif was identified as D-Trp-Phe-D-Trp-Leu-Leu, and elongation...

  1. Ghrelin receptors mediate ghrelin-induced excitation of agouti-related protein/neuropeptide Y but not pro-opiomelanocortin neurons.

    Science.gov (United States)

    Chen, Shao-Rui; Chen, Hong; Zhou, Jing-Jing; Pradhan, Geetali; Sun, Yuxiang; Pan, Hui-Lin; Li, De-Pei

    2017-08-01

    Ghrelin increases food intake and body weight by stimulating orexigenic agouti-related protein (AgRP)/neuropeptide Y (NPY) neurons and inhibiting anorexic pro-opiomelanocortin (POMC) neurons in the hypothalamus. Growth hormone secretagogue receptor (Ghsr) mediates the effect of ghrelin on feeding behavior and energy homeostasis. However, the role of Ghsr in the ghrelin effect on these two populations of neurons is unclear. We hypothesized that Ghsr mediates the effect of ghrelin on AgRP and POMC neurons. In this study, we determined whether Ghsr similarly mediates the effects of ghrelin on AgRP/NPY and POMC neurons using cell type-specific Ghsr-knockout mice. Perforated whole-cell recordings were performed on green fluorescent protein-tagged AgRP/NPY and POMC neurons in the arcuate nucleus in hypothalamic slices. In Ghsr +/+ mice, ghrelin (100 nM) significantly increased the firing activity of AgRP/NPY neurons but inhibited the firing activity of POMC neurons. In Ghsr -/- mice, the excitatory effect of ghrelin on AgRP/NPY neurons was abolished. Ablation of Ghsr also eliminated ghrelin-induced increases in the frequency of GABAergic inhibitory postsynaptic currents of POMC neurons. Strikingly, ablation of Ghsr converted the ghrelin effect on POMC neurons from inhibition to excitation. Des-acylated ghrelin had no such effect on POMC neurons in Ghsr -/- mice. In both Ghsr +/+ and Ghsr -/- mice, blocking GABA A receptors with gabazine increased the basal firing activity of POMC neurons, and ghrelin further increased the firing activity of POMC neurons in the presence of gabazine. Our findings provide unequivocal evidence that Ghsr is essential for ghrelin-induced excitation of AgRP/NPY neurons. However, ghrelin excites POMC neurons through an unidentified mechanism that is distinct from conventional Ghsr. © 2017 International Society for Neurochemistry.

  2. Importance of constitutive activity and arrestin-independent mechanisms for intracellular trafficking of the ghrelin receptor

    DEFF Research Database (Denmark)

    Holliday, Nicholas D; Holst, Birgitte; Rodionova, Elena A

    2007-01-01

    . Furthermore the interaction between phosphorylated receptors and beta-arrestin adaptor proteins has been examined. Replacement of the FLAG-tagged GhrelinR C tail with the equivalent GPR39 domain (GhR-39 chimera) preserved G(q) signaling. However in contrast to the GhrelinR, GhR-39 receptors exhibited no basal......,9), Leu(11)] substance P and a naturally occurring mutant GhrelinR (A204E) with eliminated constitutive activity inhibited basal GhrelinR internalization. Surprisingly, we found that noninternalizing GPR39 was highly phosphorylated and that basal and agonist-induced phosphorylation of the GhR-39 chimera......, but the high levels of GPR39 phosphorylation, and of the GhR-39 chimera, are not sufficient to drive endocytosis. In addition, basal GhrelinR internalization occurs independently of beta-arrestins....

  3. Genetic variation of the ghrelin activator gene ghrelin O-acyltransferase (GOAT) is associated with anorexia nervosa.

    Science.gov (United States)

    Müller, Timo D; Tschöp, Matthias H; Jarick, Ivonne; Ehrlich, Stefan; Scherag, Susann; Herpertz-Dahlmann, Beate; Zipfel, Stefan; Herzog, Wolfgang; de Zwaan, Martina; Burghardt, Roland; Fleischhaker, Christian; Klampfl, Karin; Wewetzer, Christoph; Herpertz, Stephan; Zeeck, Almut; Tagay, Sefik; Burgmer, Markus; Pfluger, Paul T; Scherag, André; Hebebrand, Johannes; Hinney, Anke

    2011-05-01

    The gastrointestinal peptide hormone ghrelin promotes food intake and increases body weight and adiposity through activation of the growth hormone secretagogue receptor (GHSR1a). To promote its biological action ghrelin is acylated at its serine 3 residue by the recently discovered ghrelin O-acyltransferase (GOAT, a.k.a. membrane-bound O-acyltransferase 4, MBOAT4). Plasma levels of total and acyl-ghrelin are negatively correlated with body-mass-index (BMI); as lower the BMI as higher plasma levels of total and acylated ghrelin and vice versa. Accordingly, plasma levels of total and acyl-ghrelin are elevated in patients with anorexia nervosa (AN) and decline upon weight regain. The importance of the endogenous Goat/ghrelin system in the neuroendocrine adaptation to fasting was recently highlighted by the observation that acyl-ghrelin mediated elevation of growth hormone (GH) release prevents starvation induced hypoglycemia in Goat(-/-) mice. The aim of this study was to test if genetic variation of GOAT is implicated in the etiology of AN. We therefore assessed association of 6 tagging single nucleotide polymorphisms (tagSNPs), which were predicted to cover 96% the common genetic variability of GOAT plus 50 kb of the 5' and 3' flanking region, in 543 German patients with AN and 612 German normal and underweight healthy controls. Based on a recessive mode of inheritance we observed some evidence for association of the G/G genotype at SNP rs10096097 with AN (nominal two-sided p = 0.031). Based on our results we conclude that genetic variation in GOAT might be implicated in the etiology of AN. Copyright © 2010 Elsevier Ltd. All rights reserved.

  4. Polymorphisms of genes coding for ghrelin and its receptor in relation to anthropometry, circulating levels of IGF-I and IGFBP-3, and breast cancer risk: a case-control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC).

    Science.gov (United States)

    Dossus, Laure; McKay, James D; Canzian, Federico; Wilkening, Stefan; Rinaldi, Sabina; Biessy, Carine; Olsen, Anja; Tjønneland, Anne; Jakobsen, Marianne U; Overvad, Kim; Clavel-Chapelon, Françoise; Boutron-Ruault, Marie-Christine; Fournier, Agnes; Linseisen, Jakob; Lukanova, Annekatrin; Boeing, Heiner; Fisher, Eva; Trichopoulou, Antonia; Georgila, Christina; Trichopoulos, Dimitrios; Palli, Domenico; Krogh, Vittorio; Tumino, Rosario; Vineis, Paolo; Quirós, José Ramon; Sala, Núria; Martínez-García, Carmen; Dorronsoro, Miren; Chirlaque, Maria-Dolores; Barricarte, Aurelio; van Duijnhoven, Fränzel J B; Bueno-de-Mesquita, H B; van Gils, Carla H; Peeters, Petra H M; Hallmans, Göran; Lenner, Per; Bingham, Sheila; Khaw, Kay Tee; Key, Tim J; Travis, Ruth C; Ferrari, Pietro; Jenab, Mazda; Riboli, Elio; Kaaks, Rudolf

    2008-07-01

    Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor, has two major functions: the stimulation of the growth hormone production and the stimulation of food intake. Accumulating evidence also suggests a role of ghrelin in cancer development. We conducted a case-control study on 1359 breast cancer cases and 2389 matched controls, nested within the European Prospective Investigation into Cancer and Nutrition, to examine the association of common genetic variants in the genes coding for ghrelin (GHRL) and its receptor (GHSR) with anthropometric measures, circulating insulin growth factor I (IGF-I) and insulin-like growth factor-binding protein 3 and breast cancer risk. Pair-wise tagging was used to select the 15 polymorphisms that represent the majority of common genetic variants across the GHRL and GHSR genes. A significant increase in breast cancer risk was observed in carriers of the GHRL rs171407-G allele (odds ratio: 1.2; 95% confidence interval: 1.0-1.4; P = 0.02). The GHRL single-nucleotide polymorphism rs375577 was associated with a 5% increase in IGF-I levels (P = 0.01). A number of GHRL and GHSR polymorphisms were associated with body mass index (BMI) and height (P between GHRL variations are associated with BMI. Furthermore, we have observed evidence for association of GHRL polymorphisms with circulating IGF-I levels and with breast cancer risk. These associations, however, might also be due to chance findings and further large studies are needed to confirm our results.

  5. Abalation of Ghrelin receptor in leptin-deficient mice has paradoxical effects on glucose homeostasis compared to Ghrelin-abalated Leptin-deficient mice

    Science.gov (United States)

    Ghrelin is produced predominantly in stomach and is known to be the endogenous ligand of the growth hormone secretagogue receptor (GHSR). Ghrelin is a GH stimulator and an orexigenic hormone. In contrast, leptin is an anorexic hormone, and leptin-deficient ob/ob mice are obese and diabetic. To study...

  6. Taking two to tango: a role for ghrelin receptor heterodimerization in stress and reward.

    Science.gov (United States)

    Schellekens, Harriët; Dinan, Timothy G; Cryan, John F

    2013-08-30

    The gut hormone, ghrelin, is the only known peripherally derived orexigenic signal. It activates its centrally expressed receptor, the growth hormone secretagogue receptor (GHS-R1a), to stimulate food intake. The ghrelin signaling system has recently been suggested to play a key role at the interface of homeostatic control of appetite and the hedonic aspects of food intake, as a critical role for ghrelin in dopaminergic mesolimbic circuits involved in reward signaling has emerged. Moreover, enhanced plasma ghrelin levels are associated with conditions of physiological stress, which may underline the drive to eat calorie-dense "comfort-foods" and signifies a role for ghrelin in stress-induced food reward behaviors. These complex and diverse functionalities of the ghrelinergic system are not yet fully elucidated and likely involve crosstalk with additional signaling systems. Interestingly, accumulating data over the last few years has shown the GHS-R1a receptor to dimerize with several additional G-protein coupled receptors (GPCRs) involved in appetite signaling and reward, including the GHS-R1b receptor, the melanocortin 3 receptor (MC3), dopamine receptors (D1 and D2), and more recently, the serotonin 2C receptor (5-HT2C). GHS-R1a dimerization was shown to affect downstream signaling and receptor trafficking suggesting a potential novel mechanism for fine-tuning GHS-R1a receptor mediated activity. This review summarizes ghrelin's role in food reward and stress and outlines the GHS-R1a dimer pairs identified to date. In addition, the downstream signaling and potential functional consequences of dimerization of the GHS-R1a receptor in appetite and stress-induced food reward behavior are discussed. The existence of multiple GHS-R1a heterodimers has important consequences for future pharmacotherapies as it significantly increases the pharmacological diversity of the GHS-R1a receptor and has the potential to enhance specificity of novel ghrelin-targeted drugs.

  7. In vivo characterization of high Basal signaling from the ghrelin receptor

    DEFF Research Database (Denmark)

    Petersen, Pia Steen; Woldbye, David P D; Madsen, Andreas Nygaard

    2009-01-01

    The receptor for the orexigenic peptide, ghrelin, is one of the most constitutively active 7TM receptors known, as demonstrated under in vitro conditions. Change in expression of a constitutively active receptor is associated with change in signaling independent of the endogenous ligand. In the f......The receptor for the orexigenic peptide, ghrelin, is one of the most constitutively active 7TM receptors known, as demonstrated under in vitro conditions. Change in expression of a constitutively active receptor is associated with change in signaling independent of the endogenous ligand....... In the following study, we found that the expression of the ghrelin receptor in the hypothalamus was up-regulated approximately 2-fold in rats both during 48-h fasting and by streptozotocin-induced hyperphagia. In a separate experiment, to probe for the effect of the high basal signaling of the ghrelin receptor...... in vivo, we used intracerebroventricular administration by osmotic pumps of a peptide [D-Arg(1), D-Phe(5), D-Trp(7,9), Leu(11)]-substance P. This peptide selectively displays inverse agonism at the ghrelin receptor as compared with an inactive control peptide with just a single amino acid substitution...

  8. Ghrelin and obestatin plasma levels and ghrelin/obestatin prepropeptide gene polymorphisms in small for gestational age infants.

    Science.gov (United States)

    Zhang, Shulian; Zhai, Guanpeng; Zhang, Jinping; Zhou, Jianguo; Chen, Chao

    2014-12-01

    To investigate plasma ghrelin and obestatin levels, and ghrelin/obestatin prepropeptide gene polymorphisms, in sequentially enrolled small for gestational age (SGA) infants. Neonates were sequentially enrolled into this study and were then subdivided into different groups, according to different study aims and availability of study materials. Consequently, plasma ghrelin and obestatin levels were measured in term SGA, term appropriate for gestational age (AGA), term large for gestational age (LGA), preterm SGA and preterm AGA neonates. Levels of both peptides were also measured in AGA infants of different gestational ages, and in term AGA neonates at different days following birth. Three ghrelin/obestatin prepropeptide gene single nucleotide polymorphisms (SNPs), Arg51Gln, Leu72Met, and Gln90Leu, were measured in neonates. The study involved a total cohort of 581 neonates. Out of 150 neonates (30 term AGA, 30 term SGA, 30 term LGA, 30 preterm AGA, and 30 preterm SGA), plasma obestatin levels were significantly higher in term SGA versus term LGA neonates (0.21 ± 0.02 ng/ml versus 0.17 ± 0.01 ng/ml, respectively). Out of a wider cohort, there were no significant differences in genotypes and allele frequencies of Arg51Gln, Leu72Met, and Gln90Leu SNPs between term SGA and AGA neonates, or between preterm SGA and AGA neonates. Ghrelin/obestatin prepropeptide polymorphisms were not found to be associated with SGA status in neonates; however, ghrelin and obestatin levels may be involved in growth and development. Further studies are required to understand the relationship between ghrelin, obestatin and prenatal development. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  9. Ghrelin receptor (GHS-R1A) agonists show potential as interventive agents during aging.

    Science.gov (United States)

    Smith, Roy G; Sun, Yuxiang; Jiang, Hong; Albarran-Zeckler, Rosie; Timchenko, Nikolai

    2007-11-01

    Administration of an orally active agonist (MK-0677) of the growth hormone secretagogue receptor (GHS-R1a) to elderly subjects restored the amplitude of endogenous episodic growth hormone (GH) release to that of young adults. Functional benefits include increased lean mass and bone density and modest improvements in strength. In old mice, a similar agonist partially restored function to the thymus and reduced tumor cell growth and metastasis. Treatment of old mice with the endogenous GHS-R1a agonist ghrelin restored a young liver phenotype. The mechanism involves inhibition of cyclin D3:cdk4/cdk6 activity and increased protein phosphatase-2A (PP2A) activity in liver nuclei, which stabilizes the dephosphorylated form of the transcription factor C/EBPalpha preventing the age-dependent formation of the C/EBPalpha-Rb-E2F4-Brm nuclear complex. By inhibiting formation of this complex, repression of E2F target genes is de-repressed and C/EBPalpha regulated expression of Pepck, a regulator of gluconeogenesis, is normalized, thereby restoring a young liver phenotype. In the brain, aging is associated with decline in dopamine function. We investigated the potential neuromodulatory role of GHS-R1a on dopamine action. Neurons were identified in the hippocampus, cortex, substantia nigra, and ventral tegmental areas that coexpressed GHS-R1a and dopamine receptor subtype-1 (D1R). Cell culture studies showed that, in the presence of ghrelin and dopamine, GHS-R and D1R form heterodimers, which modified G-protein signal transduction resulting in amplification of dopamine signaling. We speculate that aging is associated with deficient endogenous ghrelin signaling that can be rescued by intervention with GHS-R1a agonists to improve quality of life and maintain independence.

  10. Ghrelin is produced in taste cells and ghrelin receptor null mice show reduced taste responsivity to salty (NaCl and sour (citric acid tastants.

    Directory of Open Access Journals (Sweden)

    Yu-Kyong Shin

    2010-09-01

    Full Text Available The gustatory system plays a critical role in determining food preferences, food intake and energy balance. The exact mechanisms that fine tune taste sensitivity are currently poorly defined, but it is clear that numerous factors such as efferent input and specific signal transduction cascades are involved.Using immunohistochemical analyses, we show that ghrelin, a hormone classically considered to be an appetite-regulating hormone, is present within the taste buds of the tongue. Prepro-ghrelin, prohormone convertase 1/3 (PC 1/3, ghrelin, its cognate receptor (GHSR, and ghrelin-O-acyltransferase (GOAT , the enzyme that activates ghrelin are expressed in Type I, II, III and IV taste cells of mouse taste buds. In addition, ghrelin and GHSR co-localize in the same taste cells, suggesting that ghrelin works in an autocrine manner in taste cells. To determine a role for ghrelin in modifying taste perception, we performed taste behavioral tests using GHSR null mice. GHSR null mice exhibited significantly reduced taste responsivity to sour (citric acid and salty (sodium chloride tastants.These findings suggest that ghrelin plays a local modulatory role in determining taste bud signaling and function and could be a novel mechanism for the modulation of salty and sour taste responsivity.

  11. Stomach regulates energy balance via acylated ghrelin and desacyl ghrelin

    OpenAIRE

    Asakawa, A; Inui, A; Fujimiya, M; Sakamaki, R; Shinfuku, N; Ueta, Y; Meguid, M M; Kasuga, M

    2005-01-01

    Background/Aims: The gastric peptide ghrelin, an endogenous ligand for growth-hormone secretagogue receptor, has two major molecular forms: acylated ghrelin and desacyl ghrelin. Acylated ghrelin induces a positive energy balance, while desacyl ghrelin has been reported to be devoid of any endocrine activities. The authors examined the effects of desacyl ghrelin on energy balance.

  12. The Pentapeptide RM-131 Promotes Food Intake and Adiposity in Wildtype Mice but Not in Mice Lacking the Ghrelin Receptor

    DEFF Research Database (Denmark)

    Fischer, Katrin; Finan, Brian; Clemmensen, Christoffer

    2014-01-01

    The gastrointestinal peptide hormone ghrelin is the endogenous ligand of the growth hormone secretagogue receptor (a.k.a. ghrelin receptor, GHR). Currently, ghrelin is the only circulating peripheral hormone with the ability to promote a positive energy balance by stimulating food intake while...... decreasing energy expenditure and body fat utilization, as defined in rodents. Based on these and additional, beneficial effects on metabolism, the endogenous ghrelin system is considered an attractive target to treat diverse pathological conditions including those associated with eating/wasting disorders...... and cachexia. As the pharmacological potential of ghrelin is hampered by its relatively short half-life, ghrelin analogs with enhanced pharmacokinetics offer the potential to sustainably improve metabolism. One of these ghrelin analogs is the pentapeptide RM-131, which promotes food intake and adiposity...

  13. Impact of food restriction and cocaine on locomotion in ghrelin- and ghrelin-receptor knockout mice.

    Science.gov (United States)

    Clifford, Shane; Zeckler, Rosie Albarran; Buckman, Sam; Thompson, Jeff; Hart, Nigel; Wellman, Paul J; Smith, Roy G

    2011-07-01

    Food restriction (FR) augments the behavioral and reinforcing effects of psychomotor stimulants such as cocaine or amphetamine; effects that may be related to the capacity of FR to increase plasma levels of ghrelin (GHR), a 28-amino acid orexigenenic peptide linked to activation of brain dopamine systems. The present study used wild-type (WT) mice or mutant mice sustaining knockout of either GHR [GHR((-/-)) ] or of the growth hormone secretagogue receptor [GHS-R((-/-)) ] and subjected to FR or not to evaluate the role of GHR and GHS-R in cocaine-stimulated locomotion. WT, GHR((-/-)) , and GHS-R((-/-)) mice were either restricted to 60% of baseline caloric intake or allowed to free-feed (FF). Mice were treated with 0, 1.25, 2.5 and 5.0 mg/kg cocaine on separate test days (in random dose order) and forward locomotion was recorded on each drug day for 45 minutes after drug dosing. Food (and water) was available immediately after (but not during) each activity test. For FF mice, there was no interaction between cocaine and GHR status on locomotion. FR-WT mice treated with saline exhibited significant increases in anticipatory locomotion (relative to FF-WT mice), whereas FR-GHS-R((-/-)) mice did not. Cocaine significantly increased locomotion in FR-GHR((-/-)) and FR-GHS-R((-/-)) mice to the levels noted in FR-WT mice. These results suggest that GHS-R activity, but not GHR activity, is required for FR to augment food-associated anticipatory locomotion, but do not support the contention that GHR pathways are required for the capacity of FR to augment the acute effect of cocaine on locomotion. © 2010 The Authors, Addiction Biology © 2010 Society for the Study of Addiction.

  14. Ghrelin receptor inverse agonists: identification of an active peptide core and its interaction epitopes on the receptor

    DEFF Research Database (Denmark)

    Holst, Birgitte; Lang, Manja; Brandt, Erik

    2006-01-01

    [D-Arg1,D-Phe5,D-Trp7,9,Leu11]Substance P functions as a low-potency antagonist but a high-potency full inverse agonist on the ghrelin receptor. Through a systematic deletion and substitution analysis of this peptide, the C-terminal carboxyamidated pentapeptide wFwLX was identified as the core...... structure, which itself displayed relatively low inverse agonist potency. Mutational analysis at 17 selected positions in the main ligand-binding crevice of the ghrelin receptor demonstrated that ghrelin apparently interacts only with residues in the middle part of the pocket [i.e., between transmembrane...... upon both AspII:20 and GluIII:09. The identified pharmacophore can possibly serve as the basis for targeted discovery of also nonpeptide inverse agonists for the ghrelin receptor....

  15. Regulation of Ghrelin Receptor by Periodontal Bacteria In Vitro and In Vivo

    OpenAIRE

    Nokhbehsaim, Marjan; Damanaki, Anna; Nogueira, Andressa Vilas Boas; Eick, Sigrun; Memmert, Svenja; Zhou, Xiaoyan; Nanayakkara, Shanika; Götz, Werner; Cirelli, Joni Augusto; Jäger, Andreas; Deschner, James

    2017-01-01

    Ghrelin plays a major role in obesity-related diseases which have been shown to be associated with periodontitis. This study sought to analyze the expression of the functional receptor for ghrelin (GHS-R1a) in periodontal cells and tissues under microbial conditions in vitro and in vivo. The GHS-R1a expression in human periodontal cells challenged with the periodontopathogen Fusobacterium nucleatum, in gingival biopsies from periodontally healthy and diseased individuals, and from rats with a...

  16. A Significant Role of the Truncated Ghrelin Receptor GHS-R1b in Ghrelin-induced Signaling in Neurons.

    Science.gov (United States)

    Navarro, Gemma; Aguinaga, David; Angelats, Edgar; Medrano, Mireia; Moreno, Estefanía; Mallol, Josefa; Cortés, Antonio; Canela, Enric I; Casadó, Vicent; McCormick, Peter J; Lluís, Carme; Ferré, Sergi

    2016-06-17

    The truncated non-signaling ghrelin receptor growth hormone secretagogue R1b (GHS-R1b) has been suggested to simply exert a dominant negative role in the trafficking and signaling of the full and functional ghrelin receptor GHS-R1a. Here we reveal a more complex modulatory role of GHS-R1b. Differential co-expression of GHS-R1a and GHS-R1b, both in HEK-293T cells and in striatal and hippocampal neurons in culture, demonstrates that GHS-R1b acts as a dual modulator of GHS-R1a function: low relative GHS-R1b expression potentiates and high relative GHS-R1b expression inhibits GHS-R1a function by facilitating GHS-R1a trafficking to the plasma membrane and by exerting a negative allosteric effect on GHS-R1a signaling, respectively. We found a preferential Gi/o coupling of the GHS-R1a-GHS-R1b complex in HEK-293T cells and, unexpectedly, a preferential Gs/olf coupling in both striatal and hippocampal neurons in culture. A dopamine D1 receptor (D1R) antagonist blocked ghrelin-induced cAMP accumulation in striatal but not hippocampal neurons, indicating the involvement of D1R in the striatal GHS-R1a-Gs/olf coupling. Experiments in HEK-293T cells demonstrated that D1R co-expression promotes a switch in GHS-R1a-G protein coupling from Gi/o to Gs/olf, but only upon co-expression of GHS-R1b. Furthermore, resonance energy transfer experiments showed that D1R interacts with GHS-R1a, but only in the presence of GHS-R1b. Therefore, GHS-R1b not only determines the efficacy of ghrelin-induced GHS-R1a-mediated signaling but also determines the ability of GHS-R1a to form oligomeric complexes with other receptors, promoting profound qualitative changes in ghrelin-induced signaling. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. A Significant Role of the Truncated Ghrelin Receptor GHS-R1b in Ghrelin-induced Signaling in Neurons*

    Science.gov (United States)

    Navarro, Gemma; Aguinaga, David; Angelats, Edgar; Medrano, Mireia; Moreno, Estefanía; Mallol, Josefa; Cortés, Antonio; Canela, Enric I.; Casadó, Vicent; McCormick, Peter J.; Lluís, Carme; Ferré, Sergi

    2016-01-01

    The truncated non-signaling ghrelin receptor growth hormone secretagogue R1b (GHS-R1b) has been suggested to simply exert a dominant negative role in the trafficking and signaling of the full and functional ghrelin receptor GHS-R1a. Here we reveal a more complex modulatory role of GHS-R1b. Differential co-expression of GHS-R1a and GHS-R1b, both in HEK-293T cells and in striatal and hippocampal neurons in culture, demonstrates that GHS-R1b acts as a dual modulator of GHS-R1a function: low relative GHS-R1b expression potentiates and high relative GHS-R1b expression inhibits GHS-R1a function by facilitating GHS-R1a trafficking to the plasma membrane and by exerting a negative allosteric effect on GHS-R1a signaling, respectively. We found a preferential Gi/o coupling of the GHS-R1a-GHS-R1b complex in HEK-293T cells and, unexpectedly, a preferential Gs/olf coupling in both striatal and hippocampal neurons in culture. A dopamine D1 receptor (D1R) antagonist blocked ghrelin-induced cAMP accumulation in striatal but not hippocampal neurons, indicating the involvement of D1R in the striatal GHS-R1a-Gs/olf coupling. Experiments in HEK-293T cells demonstrated that D1R co-expression promotes a switch in GHS-R1a-G protein coupling from Gi/o to Gs/olf, but only upon co-expression of GHS-R1b. Furthermore, resonance energy transfer experiments showed that D1R interacts with GHS-R1a, but only in the presence of GHS-R1b. Therefore, GHS-R1b not only determines the efficacy of ghrelin-induced GHS-R1a-mediated signaling but also determines the ability of GHS-R1a to form oligomeric complexes with other receptors, promoting profound qualitative changes in ghrelin-induced signaling. PMID:27129257

  18. Polymorphisms of genes coding for ghrelin and its receptor in relation to anthropometry, circulating levels of IGF-I and IGFBP-3, and breast cancer risk : a case-control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC)

    NARCIS (Netherlands)

    Dossus, Laure; Mckay, James D.; Canzian, Federico; Wilkening, Stefan; Rinaldi, Sabina; Biessy, Carine; Olsen, Anja; Tjonneland, Anne; Jakobsen, Marianne U.; Overvad, Kim; Clavel-Chapelon, Francoise; Boutron-Ruault, Marie-Christine; Fournier, Agnes; Linseisen, Jakob; Lukanova, Annekatrin; Boeing, Heiner; Fisher, Eva; Trichopoulou, Antonia; Georgila, Christina; Trichopoulos, Dimitrios; Palli, Domenico; Krogh, Vittorio; Tumino, Rosario; Vineis, Paolo; Quiros, Jose Ramon; Sala, Nuria; Martinez-Garcia, Carmen; Dorronsoro, Miren; Chirlaque, Maria-Dolores; Barricarte, Aurelio; van Duijnhoven, Franzel J. B.; Bueno-de-Mesquita, H. B.; van Gils, Carla H.; Peeters, Petra H. M.; Hallmans, Goran; Lenner, Per; Bingham, Sheila; Khaw, Kay Tee; Key, Tim J.; Travis, Ruth C.; Ferrari, Pietro; Jenab, Mazda; Riboli, Elio; Kaaks, Rudolf

    Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor, has two major functions: the stimulation of the growth hormone production and the stimulation of food intake. Accumulating evidence also suggests a role of ghrelin in cancer development. We conducted a case-control study on

  19. Evidence Supporting a Role for Constitutive Ghrelin Receptor Signaling in Fasting-Induced Hyperphagia in Male Mice.

    Science.gov (United States)

    Fernandez, Gimena; Cabral, Agustina; Andreoli, María F; Labarthe, Alexandra; M'Kadmi, Céline; Ramos, Jorge G; Marie, Jacky; Fehrentz, Jean-Alain; Epelbaum, Jacques; Tolle, Virginie; Perello, Mario

    2018-02-01

    Ghrelin is a potent orexigenic peptide hormone that acts through the growth hormone secretagogue receptor (GHSR), a G protein-coupled receptor highly expressed in the hypothalamus. In vitro studies have shown that GHSR displays a high constitutive activity, whose physiological relevance is uncertain. As GHSR gene expression in the hypothalamus is known to increase in fasting conditions, we tested the hypothesis that constitutive GHSR activity at the hypothalamic level drives the fasting-induced hyperphagia. We found that refed wild-type (WT) mice displayed a robust hyperphagia that continued for 5 days after refeeding and changed their food intake daily pattern. Fasted WT mice showed an increase in plasma ghrelin levels, as well as in GHSR expression levels and ghrelin binding sites in the hypothalamic arcuate nucleus. When fasting-refeeding responses were evaluated in ghrelin- or GHSR-deficient mice, only the latter displayed an ∼15% smaller hyperphagia, compared with WT mice. Finally, fasting-induced hyperphagia of WT mice was significantly smaller in mice centrally treated with the GHSR inverse agonist K-(D-1-Nal)-FwLL-NH2, compared with mice treated with vehicle, whereas it was unaffected in mice centrally treated with the GHSR antagonists D-Lys3-growth hormone-releasing peptide 6 or JMV2959. Taken together, genetic models and pharmacological results support the notion that constitutive GHSR activity modulates the magnitude of the compensatory hyperphagia triggered by fasting. Thus, the hypothalamic GHSR signaling system could affect the set point of daily food intake, independently of plasma ghrelin levels, in situations of negative energy balance. Copyright © 2018 Endocrine Society.

  20. Association of pro-ghrelin and GHS-R1A gene polymorphisms and haplotypes with heavy alcohol use and body mass.

    Science.gov (United States)

    Landgren, Sara; Jerlhag, Elisabet; Zetterberg, Henrik; Gonzalez-Quintela, Arturo; Campos, Joaquin; Olofsson, Ulrica; Nilsson, Staffan; Blennow, Kaj; Engel, Jörgen A

    2008-12-01

    Ghrelin, an orexigenic peptide, acts on growth hormone secretagogue receptors (GHS-R1A), expressed in the hypothalamus as well as in important reward nodes such as the ventral tegmental area. Interestingly, ghrelin has been found to activate an important part of the reward systems, i.e., the cholinergic-dopaminergic reward link. Additionally, the rewarding and neurochemical properties of alcohol are, at least in part, mediated via this reward link. There is comorbidity between alcohol dependence and eating disorders. Thus, plasma levels of ghrelin are altered in patients with addictive behaviors such as alcohol and nicotine dependence and in binge eating disorder. This overlap prompted as to investigate the pro-ghrelin and GHS-R1A genes in a haplotype analysis of heavy alcohol-using individuals. A total of 417 Spanish individuals (abstainers, moderate, and heavy alcohol drinkers) were investigated in a haplotype analysis of the pro-ghrelin and GHS-R1A genes. Tag SNPs were chosen using HapMap data and the Tagger and Haploview softwares. These SNPs were then genotyped using TaqMan Allelic Discrimination. SNP rs2232165 of the GHS-R1A gene was associated with heavy alcohol consumption and SNP rs2948694 of the same gene as well as haplotypes of both the pro-ghrelin and the GHS-R1A genes were associated with body mass in heavy alcohol consuming individuals. The present findings are the first to disclose an association between the pro-ghrelin and GHS-R1A genes and heavy alcohol use, further strengthening the role of the ghrelin system in addictive behaviors and brain reward.

  1. Blockade of central nicotine acetylcholine receptor signaling attenuate ghrelin-induced food intake in rodents.

    Science.gov (United States)

    Dickson, S L; Hrabovszky, E; Hansson, C; Jerlhag, E; Alvarez-Crespo, M; Skibicka, K P; Molnar, C S; Liposits, Z; Engel, J A; Egecioglu, E

    2010-12-29

    Here we sought to determine whether ghrelin's central effects on food intake can be interrupted by nicotine acetylcholine receptor (nAChR) blockade. Ghrelin regulates mesolimbic dopamine neurons projecting from the ventral tegmental area (VTA) to the nucleus accumbens, partly via cholinergic VTA afferents originating in the laterodorsal tegmental area (LDTg). Given that these cholinergic projections to the VTA have been implicated in natural as well as drug-induced reinforcement, we sought to investigate the role of cholinergic signaling in ghrelin-induced food intake as well as fasting-induced food intake, for which endogenous ghrelin has been implicated. We found that i.p. treatment with the non-selective centrally active nAChR antagonist, mecamylamine decreased fasting-induced food intake in both mice and rats. Moreover, central administration of mecamylamine decreased fasting-induced food intake in rats. I.c.v. ghrelin-induced food intake was suppressed by mecamylamine i.p. but not by hexamethonium i.p., a peripheral nAChR antagonist. Furthermore, mecamylamine i.p. blocked food intake following ghrelin injection into the VTA. Expression of the ghrelin receptor, the growth hormone secretagogue receptor 1A, was found to co-localize with choline acetyltransferase, a marker of cholinergic neurons, in the LDTg. Finally, mecamylamine treatment i.p. decreased the ability of palatable food to condition a place preference. These data suggest that ghrelin-induced food intake is partly mediated via nAChRs and that nicotinic blockade decreases the rewarding properties of food. Copyright © 2010 IBRO. Published by Elsevier Ltd. All rights reserved.

  2. In1-ghrelin, a splice variant of ghrelin gene, is associated with the evolution and aggressiveness of human neuroendocrine tumors: Evidence from clinical, cellular and molecular parameters

    Science.gov (United States)

    Gahete, Manuel D.; Ramos-Levi, Ana; Ibáñez-Costa, Alejandro; Rivero-Cortés, Esther; Serrano-Somavilla, Ana; Adrados, Magdalena; Culler, Michael D.; Castaño, Justo P.; Marazuela, Mónica

    2015-01-01

    Ghrelin system comprises a complex family of peptides, receptors (GHSRs), and modifying enzymes [e.g. ghrelin-O-acyl-transferase (GOAT)] that control multiple pathophysiological processes. Aberrant alternative splicing is an emerging cancer hallmark that generates altered proteins with tumorigenic capacity. Indeed, In1-ghrelin and truncated-GHSR1b splicing variants can promote development/progression of certain endocrine-related cancers. Here, we determined the expression levels of key ghrelin system components in neuroendocrine tumor (NETs) and explored their potential functional role. Twenty-six patients with NETs were prospectively/retrospectively studied [72 samples from primary and metastatic tissues (30 normal/42 tumors)] and clinical data were obtained. The role of In1-ghrelin in aggressiveness was studied in vitro using NET cell lines (BON-1/QGP-1). In1-ghrelin, GOAT and GHSR1a/1b expression levels were elevated in tumoral compared to normal/adjacent tissues. Moreover, In1-ghrelin, GOAT, and GHSR1b expression levels were positively correlated within tumoral, but not within normal/adjacent samples, and were higher in patients with progressive vs. with stable/cured disease. Finally, In1-ghrelin increased aggressiveness (e.g. proliferation/migration) of NET cells. Altogether, our data strongly suggests a potential implication of ghrelin system in the pathogenesis and/or clinical outcome of NETs, and warrant further studies on their possible value for the future development of molecular biomarkers with diagnostic/prognostic/therapeutic value. PMID:26124083

  3. Ghrelin receptor antagonism of hyperlocomotion in cocaine-sensitized mice requires βarrestin-2.

    Science.gov (United States)

    Toth, Krisztian; Slosky, Lauren M; Pack, Thomas F; Urs, Nikhil M; Boone, Peter; Mao, Lan; Abraham, Dennis; Caron, Marc G; Barak, Lawrence S

    2018-01-01

    The "brain-gut" peptide ghrelin, which mediates food-seeking behaviors, is recognized as a very strong endogenous modulator of dopamine (DA) signaling. Ghrelin binds the G protein-coupled receptor GHSR1a, and administration of ghrelin increases the rewarding properties of psychostimulants while ghrelin receptor antagonists decrease them. In addition, the GHSR1a signals through βarrestin-2 to regulate actin/stress fiber rearrangement, suggesting βarrestin-2 participation in the regulation of actin-mediated synaptic plasticity for addictive substances like cocaine. The effects of ghrelin receptor ligands on reward strongly suggest that modulation of ghrelin signaling could provide an effective strategy to ameliorate undesirable behaviors arising from addiction. To investigate this possibility, we tested the effects of ghrelin receptor antagonism in a cocaine behavioral sensitization paradigm using DA neuron-specific βarrestin-2 KO mice. Our results show that these mice sensitize to cocaine as well as wild-type littermates. The βarrestin-2 KO mice, however, no longer respond to the locomotor attenuating effects of the GHSR1a antagonist YIL781. The data presented here suggest that the separate stages of addictive behavior differ in their requirements for βarrestin-2 and show that pharmacological inhibition of βarrestin-2 function through GHSR1a antagonism is not equivalent to the loss of βarrestin-2 function achieved by genetic ablation. These data support targeting GHSR1a signaling in addiction therapy but indicate that using signaling biased compounds that modulate βarrestin-2 activity differentially from G protein activity may be required. © 2017 Wiley Periodicals, Inc.

  4. Caloric Restriction Protects against Lactacystin-Induced Degeneration of Dopamine Neurons Independent of the Ghrelin Receptor

    Directory of Open Access Journals (Sweden)

    Jessica Coppens

    2017-03-01

    Full Text Available Parkinson’s disease (PD is a neurodegenerative disorder, characterized by a loss of dopamine (DA neurons in the substantia nigra pars compacta (SNc. Caloric restriction (CR has been shown to exert ghrelin-dependent neuroprotective effects in the 1-methyl-4-phenyl-1,2,3,6-tetrathydropyridine (MPTP-based animal model for PD. We here investigated whether CR is neuroprotective in the lactacystin (LAC mouse model for PD, in which proteasome disruption leads to the destruction of the DA neurons of the SNc, and whether this effect is mediated via the ghrelin receptor. Adult male ghrelin receptor wildtype (WT and knockout (KO mice were maintained on an ad libitum (AL diet or on a 30% CR regimen. After 3 weeks, LAC was injected unilaterally into the SNc, and the degree of DA neuron degeneration was evaluated 1 week later. In AL mice, LAC injection significanty reduced the number of DA neurons and striatal DA concentrations. CR protected against DA neuron degeneration following LAC injection. However, no differences were observed between ghrelin receptor WT and KO mice. These results indicate that CR can protect the nigral DA neurons from toxicity related to proteasome disruption; however, the ghrelin receptor is not involved in this effect.

  5. Regulation of Ghrelin Receptor by Periodontal Bacteria In Vitro and In Vivo.

    Science.gov (United States)

    Nokhbehsaim, Marjan; Damanaki, Anna; Nogueira, Andressa Vilas Boas; Eick, Sigrun; Memmert, Svenja; Zhou, Xiaoyan; Nanayakkara, Shanika; Götz, Werner; Cirelli, Joni Augusto; Jäger, Andreas; Deschner, James

    2017-01-01

    Ghrelin plays a major role in obesity-related diseases which have been shown to be associated with periodontitis. This study sought to analyze the expression of the functional receptor for ghrelin (GHS-R1a) in periodontal cells and tissues under microbial conditions in vitro and in vivo . The GHS-R1a expression in human periodontal cells challenged with the periodontopathogen Fusobacterium nucleatum , in gingival biopsies from periodontally healthy and diseased individuals, and from rats with and without ligature-induced periodontitis was analyzed by real-time PCR, immunocytochemistry, and immunofluorescence. F. nucleatum induced an initial upregulation and subsequent downregulation of GHS-R1a in periodontal cells. In rat experimental periodontitis, the GHS-R1a expression at periodontitis sites was increased during the early stage of periodontitis, but significantly reduced afterwards, when compared with healthy sites. In human gingival biopsies, periodontally diseased sites showed a significantly lower GHS-R1a expression than the healthy sites. The expression of the functional ghrelin receptor in periodontal cells and tissues is modulated by periodontal bacteria. Due to the downregulation of the functional ghrelin receptor by long-term exposure to periodontal bacteria, the anti-inflammatory actions of ghrelin may be diminished in chronic periodontal infections, which could lead to an enhanced periodontal inflammation and tissue destruction.

  6. Hypothalamic peroxisome proliferator-activated receptor gamma regulates ghrelin production and food intake.

    Science.gov (United States)

    Li, Qingjie; Yu, Quan; Lin, Li; Zhang, Heng; Peng, Miao; Jing, Chunxia; Xu, Geyang

    2018-04-09

    Peroxisome proliferator-activated receptor-γ (PPARγ) regulates fatty acid storage, glucose metabolism, and food intake. Ghrelin, a gastric hormone, provides a hunger signal to the central nervous system to stimulate appetite. However, the effects of PPARγ on ghrelin production are still unclear. In the present study, the effects of PPARγ on ghrelin production were examined in lean- or high-fat diet-induced obese (DIO) C57BL/6J mice and mHypoE-42 cells, a hypothalamic cell line. 3rd intracerebroventricular injection of adenoviral-directed overexpression of PPARγ (Ad-PPARγ) reduced hypothalamic and plasma ghrelin, food intake in both lean C57BL/6J mice and diet-induced obese mice. These changes were associated with a significant increase in mechanistic target of rapamycin complex 1 (mTORC1) activity. Overexpression of PPARγ enhanced mTORC1 signaling and suppressed ghrelin production in cultured mHypoE-42 cells. Our results suggest that hypothalamic PPARγ plays a vital role in ghrelin production and food intake in mice. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. Ghrelin Gene Variants Influence on Metabolic Syndrome Components in Aged Spanish Population

    OpenAIRE

    Mora, Mireia; Adam, Victoria; Palomera, Elisabet; Blesa, Sebastian; Díaz, Gonzalo; Buquet, Xavier; Serra-Prat, Mateu; Martín-Escudero, Juan Carlos; Palanca, Ana; Chaves, Javier Felipe; Puig-Domingo, Manuel

    2015-01-01

    BACKGROUND: The role of genetic variations within the ghrelin gene on cardiometabolic profile and nutritional status is still not clear in humans, particularly in elderly people. OBJECTIVES: We investigated six SNPs of the ghrelin gene and their relationship with metabolic syndrome (MS) components. SUBJECTS AND METHODS: 824 subjects (413 men/411 women, age 77.31±5.04) participating in the Mataró aging study (n = 310) and the Hortega study (n = 514) were analyzed. Anthropometric variables, ghr...

  8. From Belly to Brain: Targeting the Ghrelin Receptor in Appetite and Food Intake Regulation

    Directory of Open Access Journals (Sweden)

    Ken Howick

    2017-01-01

    Full Text Available Ghrelin is the only known peripherally-derived orexigenic hormone, increasing appetite and subsequent food intake. The ghrelinergic system has therefore received considerable attention as a therapeutic target to reduce appetite in obesity as well as to stimulate food intake in conditions of anorexia, malnutrition and cachexia. As the therapeutic potential of targeting this hormone becomes clearer, it is apparent that its pleiotropic actions span both the central nervous system and peripheral organs. Despite a wealth of research, a therapeutic compound specifically targeting the ghrelin system for appetite modulation remains elusive although some promising effects on metabolic function are emerging. This is due to many factors, ranging from the complexity of the ghrelin receptor (Growth Hormone Secretagogue Receptor, GHSR-1a internalisation and heterodimerization, to biased ligand interactions and compensatory neuroendocrine outputs. Not least is the ubiquitous expression of the GHSR-1a, which makes it impossible to modulate centrallymediated appetite regulation without encroaching on the various peripheral functions attributable to ghrelin. It is becoming clear that ghrelin’s central signalling is critical for its effects on appetite, body weight regulation and incentive salience of food. Improving the ability of ghrelin ligands to penetrate the blood brain barrier would enhance central delivery to GHSR-1a expressing brain regions, particularly within the mesolimbic reward circuitry.

  9. Taking Two to Tango: A Role for Ghrelin Receptor Heterodimerization in Stress and Reward

    Directory of Open Access Journals (Sweden)

    Harriet eSchellekens

    2013-08-01

    Full Text Available The gut hormone, ghrelin, is the only known peripherally derived orexigenic signal. It activates its centrally expressed receptor, the growth hormone secretagogue receptor (GHS-R1a, to stimulate food intake. The ghrelin signalling system has recently been suggested to play a key role at the interface of homeostatic control of appetite and the hedonic aspects of food intake, as a critical role for ghrelin in dopaminergic mesolimbic circuits involved in reward signalling has emerged. Moreover, enhanced plasma ghrelin levels are associated with conditions of physiological stress, which may underline the drive to eat calorie-dense ‘comfort-foods’ and signifies a role for ghrelin in stress-induced food reward behaviours. These complex and diverse functionalities of the ghrelinergic system are not yet fully elucidated and likely involve crosstalk with additional signalling systems. Interestingly, accumulating data over the last few years has shown the GHS-R1a receptor to dimerize with several additional G-protein coupled receptors (GPCRs involved in appetite signalling and reward, including the GHS-R1b receptor, the melanocortin 3 receptor (MC3, dopamine receptors (D1 and D2, and more recently, the serotonin 2C receptor (5-HT2C. GHS-R1a dimerization was shown to affect downstream signalling and receptor trafficking suggesting a potential novel mechanism for fine-tuning GHS-R1a receptor mediated activity. This review summarizes ghrelin’s role in food reward and stress and outlines the GHS-R1a dimer pairs identified to date. In addition, the downstream signalling and potential functional consequences of dimerization of the GHS-R1a receptor in appetite and stress-induced food reward behaviour are discussed. The existence of multiple GHS-R1a heterodimers has important consequences for future pharmacotherapies as it significantly increases the pharmacological diversity of the GHS-R1a receptor and has the potential to enhance specificity of novel

  10. Influence of ghrelin gene polymorphisms on hypertension and atherosclerotic disease.

    Science.gov (United States)

    Berthold, Heiner K; Giannakidou, Eleni; Krone, Wilhelm; Trégouët, David-Alexandre; Gouni-Berthold, Ioanna

    2010-02-01

    Ghrelin is involved in several metabolic and cardiovascular processes. Recent evidence suggests its involvement in blood pressure regulation and hypertension. The aim of the study was to determine associations of single-nucleotide polymorphisms (SNPs) and haplotypes of the ghrelin gene (GHRL) with hypertension and atherosclerotic disease. Six GHRL SNPs (rs27647, rs26802, rs34911341, rs696217, rs4684677 and a -473G/A (with no assigned rsID)) were investigated in a sample of 1143 hypertensive subjects and 1489 controls of Caucasian origin. Both single-locus and haplotype association analyses were performed. In single-locus analyses, only the non-synonymous rs34911341 was associated with hypertension (odds ratio (OR)=1.95 (95% confidence interval (CI): 1.26-3.02), P=0.003). Six common haplotypes with frequency >1% were inferred from the studied GHRL SNPs, and their frequency distribution was significantly different between hypertensive subjects and controls (chi(2)=12.96 with 5 d.f. (degree of freedom), P=0.024). The effect of rs26802 was found to be significantly (P=0.017) modulated by other GHRL SNPs, as its C allele conferred either an increased risk (OR=1.30 (1.08-1.57), P=0.005) or a decreased risk (OR=0.50 (0.23-1.06), P=0.07) of hypertension according to the two different haplotypes on which it can be found. No association of GHRL SNPs or haplotypes with atherosclerotic disease was observed. In conclusion, we observed statistical evidence for association between GHRL SNPs and risk of hypertension.

  11. The Leu72Met polymorphism of the ghrelin gene is significantly associated with binge eating disorder.

    Science.gov (United States)

    Monteleone, Palmiero; Tortorella, Alfonso; Castaldo, Eloisa; Di Filippo, Carmela; Maj, Mario

    2007-02-01

    The pathophysiological mechanisms underlying binge eating disorder are poorly understood. Evidence exists for the fact that abnormalities in peptides involved in the regulation of appetite, including ghrelin, may play a role in binge eating behavior. Genes involved in the ghrelin physiology may therefore contribute to the biological vulnerability to binge eating disorder. We examined whether two polymorphisms of the ghrelin gene, the G152A (Arg51Gln) and C214A (Leu72Met), were associated with binge eating disorder. Ninety obese or nonobese women with binge eating disorder and 119 normal weight women were genotyped at the ghrelin gene. Statistical analyses showed that the Leu72Met ghrelin gene variant was significantly more frequent in binge eating disorder patients (chi2=5.940; d.f.=1, P=0.01) and was associated with a moderate, but significant risk to develop binge eating disorder (odds ratio=2.725, 95% confidence interval: 1.168-6.350). Although these data should be regarded as preliminary because of the small sample size, they suggest that the Leu72Met ghrelin gene variant may contribute to the genetic susceptibility to binge eating disorder.

  12. Polymorphisms and haplotypes in the bovine neuropeptide Y, growth hormone receptor, ghrelin, insulin-like growth factor 2, and uncoupling proteins 2 and 3 genes and their associations with measures of growth, performance, feed efficiency, and carcass merit in beef cattle.

    Science.gov (United States)

    Sherman, E L; Nkrumah, J D; Murdoch, B M; Li, C; Wang, Z; Fu, A; Moore, S S

    2008-01-01

    Genes that regulate metabolism and energy partitioning have the potential to influence economically important traits in farm animals, as do polymorphisms within these genes. In the current study, SNP in the bovine neuropeptide Y (NPY), growth hormone receptor (GHR), ghrelin (GHRL), uncoupling proteins 2 and 3 (UCP2 and UCP3), IGF2, corticotrophin-releasing hormone (CRH), cocaine and amphetamine regulated transcript (CART), melanocortin-4 receptor (MC4R), proopiomelanocortin (POMC), and GH genes were evaluated for associations with growth, feed efficiency, and carcass merit in beef steers. In total, 24 SNP were evaluated for associations with these traits and haplotypes were constructed within each gene when 2 or more SNP showed significant associations. An A/G SNP located in intron 4 of the GHR gene had the largest effects on BW of the animals (dominance effect P GHRL gene tended to show effects on residual feed intake, FCR, and partial efficiency of growth (P < 0.10). The IGF2 SNP most strongly affected LM area (P < 0.01), back fat, ADG, and FCR (P < 0.05). The SNP in the CART, MC4R, POMC, GH, and CRH genes did not show associations at P < 0.05 with any of the traits. Although most of the SNP that showed associations do not cause amino acid changes, these SNP could be linked to other yet to be detected causative mutations or nearby QTL. It will be very important to verify these results in other cattle populations.

  13. Activation of somatostatin 2 receptors in the brain and the periphery induces opposite changes in circulating ghrelin levels: functional implications

    Directory of Open Access Journals (Sweden)

    Andreas eStengel

    2013-01-01

    Full Text Available Somatostatin is an important modulator of neurotransmission in the central nervous system and acts as a potent inhibitor of hormone and exocrine secretion and regulator of cell proliferation in the periphery. These pleiotropic actions occur through interaction with five G-protein coupled somatostatin receptor subtypes (sst1-5 that are widely expressed in the brain and peripheral organs. The characterization of somatostatin’s effects can be investigated by pharmacological or genetic approaches using newly developed selective sst agonists and antagonists and mice lacking specific sst subtypes. Recent evidence points towards a divergent action of somatostatin in the brain and in the periphery to regulate circulating levels of ghrelin, an orexigenic hormone produced by the endocrine X/A-like cells in the gastric mucosa. Somatostatin interacts with the sst2 in the brain to induce an increase in basal ghrelin plasma levels and counteracts the visceral stress-related decrease in circulating ghrelin in rats. By contrast, stimulation of peripheral somatostatin-sst2 signaling results in the inhibition of basal ghrelin release and mediates the postoperative decrease in circulating ghrelin in rats. The peripheral sst2-mediated reduction of plasma ghrelin is likely to involve a paracrine action of D-cell derived somatostatin acting on sst2 bearing X/A-like ghrelin cells in the gastric mucosa. The other member of the somatostatin family, named cortistatin, in addition to binding to sst1-5 also directly interacts with the ghrelin receptor and therefore may simultaneously modulate ghrelin release and actions at target sites bearing ghrelin receptors representing a link between the ghrelin and somatostatin systems.

  14. Glucose impairment and ghrelin gene variants are associated to cognitive dysfunction.

    Science.gov (United States)

    Mora, M; Mansego, M L; Serra-Prat, M; Palomera, E; Boquet, X; Chaves, J F; Puig-Domingo, M

    2014-04-01

    Cognitive state and brain volume have been related to body mass index, abdominal fat, waist-hip ratio, components of metabolic syndrome (MS) and ghrelin. Genetic variations within the ghrelin gene have been recently associated to MS. The aim of our study was to investigate cognitive state by Mini-Mental State Examination (MMSE) in relation to MS components (ATP-III criteria) and ghrelin gene polymorphisms in dwelling individuals aged ≥70. 280 subjects (137 men/143 women, age 77.03 ± 5.92) from the Mataró Ageing Study were included. Individuals were phenotypically characterized by anthropometric variables, lipids, glucose, blood pressure and MMSE. SNPs -501AC (rs26802), -994CT (rs26312), -604GA (rs27647), M72L (rs696217) and L90G (rs4684677) of the ghrelin gene were studied. Genotypes were determined by polymerase chain reaction and SNapshot minisequencing. 22.1 % had MMSE Ghrelin SNPs were associated to MMSE: M72L C/A genotype showed lower score than C/C (p = 0.032, after adjusting for confounders 0.049); L90G A/T genotype showed lower score than A/A (p = 0.054, after adjusting 0.005). MMSE Ghrelin gene variant influence cognitive function in old dwelling individuals participating in the Mataró Ageing Study.

  15. Ghrelin receptor agonists as novel breast cancer therapeutics

    OpenAIRE

    CHEUK MAN CHERIE AU

    2017-01-01

    The human cell studies and the live mouse studies are intended to provide the information that is needed to apply therapies to treat breast cancer patients, based on our novel discoveries. We believe that des-acyl ghrelin-like compounds will be novel breast cancer therapeutics while avoiding well-documented serious side effects, including joint pain, osteoporosis or endometrial cancer. Our findings could therefore improve the quality of life of women treated for breast cancer, improve complia...

  16. Circulating Ghrelin, Leptin, and Soluble Leptin Receptor Concentrations and Cardiometabolic Risk Factors in a Community-Based Sample

    OpenAIRE

    Ingelsson, Erik; Larson, Martin G.; Yin, Xiaoyan; Wang, Thomas J.; Meigs, James B.; Lipinska, Izabella; Benjamin, Emelia J.; Keaney, John F.; Vasan, Ramachandran S.

    2008-01-01

    Context: The conjoint effects and relative importance of ghrelin, leptin, and soluble leptin receptor (sOB-R), adipokines involved in appetite control and energy expenditure in mediating cardiometabolic risk, is unknown.

  17. Polymorphisms in ghrelin and neuropeptide Y genes are associated with non-Hodgkin lymphoma.

    Science.gov (United States)

    Skibola, Danica R; Smith, Martyn T; Bracci, Paige M; Hubbard, Alan E; Agana, Luz; Chi, Shawn; Holly, Elizabeth A

    2005-05-01

    We previously reported a positive association among body mass index, single nucleotide polymorphisms (SNP) in the leptin and leptin receptor genes that are involved in body weight regulation, and non-Hodgkin lymphoma (NHL). Polymorphisms in the ghrelin (GHRL) and neuropeptide Y (NPY) genes were examined in the same population-based case-control study of NHL to further explore the role of genes involved in energy homeostasis and obesity in susceptibility to NHL. Ghrelin is an orexigenic hormone that induces NPY release and inhibits proinflammatory cytokines via its antagonistic relationship with leptin. NPY is a potent appetite stimulator controlled by ghrelin and leptin and also acts as a mediator of immune function. DNA from 458 cases and 812 controls was genotyped. Among genotyped GHRL SNPs, the variant allele for GHRL -4427G>A was inversely associated with all NHL [odds ratios (OR), 0.78; 95% confidence interval (95% CI), 0.59-1.0] and more specifically with diffuse large cell lymphoma (DLCL; homozygous variant: OR, 0.31; 95% CI, 0.13-0.74). Another SNP, GHRL 5179A>G, decreased the risk of DLCL (homozygous variant: OR, 0.35; 95% CI, 0.10-1.2). NPY -485T>C, 1258G>A, and 5671C>T were in total linkage disequilibrium (D' = 0.99) and the homozygous variants were associated with an increased risk of NHL in NPY SNPs -485T>C (OR, 1.7; 95% CI, 1.1-2.5), 1258G>A (OR, 1.7; 95% CI, 1.1-2.5), and 5671C>T (OR, 1.9; 95% CI, 1.3-2.8). When stratified by subtype, the variant allele for NPY 1128T>C was positively associated with follicular lymphoma (OR, 2.3; 95% CI, 1.1-4.9) as were homozygous variants for NPY SNPs -485T>C (OR, 2.4; 95% CI, 1.3-4.4), 1258G>A (OR, 2.0; 95% CI, 1.1-3.5), and 5671C>T (OR, 1.8; 95% CI, 1.1-3.0). These results add further support for the hypothesis that SNPs in energy-regulating genes affect risk of NHL.

  18. Sequencing analysis of ghrelin gene 5' flanking region: relations between the sequence variants, fasting plasma total ghrelin concentrations, and body mass index.

    Science.gov (United States)

    Vartiainen, Johanna; Kesäniemi, Y Antero; Ukkola, Olavi

    2006-10-01

    Ghrelin is a 28-amino-acid peptide with several functions linked to energy metabolism. Low ghrelin plasma concentrations are associated with obesity, hypertension, and type 2 diabetes mellitus, whereas high concentrations reflect states of negative energy balance. Several studies addressing the hormonal and neural regulation of ghrelin gene expression have been carried out, but the role of genetic factors in the regulation of ghrelin plasma levels remains unclear. To elucidate the role of genetic factors in the regulation of ghrelin expression, we screened 1657 nucleotides of the ghrelin gene 5' flanking region (promoter and possible regulatory sites) for new sequential variations from patient samples with low (n = 50) and high (n = 50) fasting plasma total ghrelin concentrations (low- and high-ghrelin groups). Eleven single nucleotide polymorphisms (SNPs), 3 of which were rare variants (allelic frequency less than 1%) were found in our population. The genotype distribution patterns of the SNPs did not differ between the study groups, except for SNP-501A>C (P = .039). In addition, the SNP-01A>C was associated with body mass index (BMI) (P = .018). This variant was studied further in our large and well-defined Oulu Project Elucidating Risk for Atherosclerosis (OPERA) cohort (n = 1045) by the restriction fragment length polymorphism (RFLP) technique. No significant association of SNP-501A>C genotypes with fasting ghrelin plasma concentrations was found in the whole OPERA population. However, the association of this SNP with BMI and with waist circumference reached statistical significance in OPERA (P = .047 and .049, respectively), remaining of borderline significance for BMI after adjustments (P = .055). The results indicate that factors other than the 11 SNPs found in this study in the 5' flanking region of ghrelin gene are the main determinants of ghrelin plasma levels. However, SNP-501 A>C genotype distribution seems to be different in subjects having the highest

  19. An aromatic region to induce a switch between agonism and inverse agonism at the ghrelin receptor

    DEFF Research Database (Denmark)

    Els, Sylvia; Schild, Enrico; Petersen, Pia Steen

    2012-01-01

    The ghrelin receptor displays a high constitutive activity suggested to be involved in the regulation of appetite and food intake. Here, we have created peptides with small changes in the core binding motif -wFw- of the hexapeptide KwFwLL-NH(2) that can swap the peptide behavior from inverse......-tryptophane at position 4 with 1-naphthyl-d-alanine (d-1-Nal) and 2-naphthyl-d-alanine (d-2-Nal) induces agonism in functional assays. Competitive binding studies showed a high affinity of the inverse agonist K-(d-1-Nal)-FwLL-NH(2) at the ghrelin receptor. Moreover, mutagenesis studies of the receptor revealed key...

  20. A Novel Non-Peptidic Agonist of the Ghrelin Receptor with Orexigenic Activity In vivo

    Science.gov (United States)

    Pastor-Cavada, Elena; Pardo, Leticia M.; Kandil, Dalia; Torres-Fuentes, Cristina; Clarke, Sarah L.; Shaban, Hamdy; McGlacken, Gerard P.; Schellekens, Harriet

    2016-11-01

    Loss of appetite in the medically ill and ageing populations is a major health problem and a significant symptom in cachexia syndromes, which is the loss of muscle and fat mass. Ghrelin is a gut-derived hormone which can stimulate appetite. Herein we describe a novel, simple, non-peptidic, 2-pyridone which acts as a selective agonist for the ghrelin receptor (GHS-R1a). The small 2-pyridone demonstrated clear agonistic activity in both transfected human cells and mouse hypothalamic cells with endogenous GHS-R1a receptor expression. In vivo tests with the hit compound showed significant increased food intake following peripheral administration, which highlights the potent orexigenic effect of this novel GHS-R1a receptor ligand.

  1. Modulation of the constitutive activity of the ghrelin receptor by use of pharmacological tools and mutagenesis.

    Science.gov (United States)

    Mokrosiński, Jacek; Holst, Birgitte

    2010-01-01

    Ghrelin and its receptor are important regulators of metabolic functions, including appetite, energy expenditure, fat accumulation, and growth hormone (GH) secretion. The ghrelin receptor is characterized by an ability to signal even without any ligand present with approximately 50% of the maximally ghrelin-induced efficacy-a feature that may have important physiological implications. The high basal signaling can be modulated either by administration of specific ligands or by engineering of mutations in the receptor structure. [D-Arg(1), D-Phe(5), D-Trp(7,9), Leu(11)]-substance P was the first inverse agonist to be identified for the ghrelin receptor, and this peptide has been used as a starting point for identification of the structural requirements for inverse agonist properties in the ligand. The receptor binding core motif was identified as D-Trp-Phe-D-Trp-Leu-Leu, and elongation of this peptide in the amino-terminal end determined the efficacy. Attachment of a positively charged amino acid was responsible for full inverse agonism, whereas an alanin converted the peptide into a partial agonist. Importantly, by use of mutational mapping of the residues critical for the modified D-Trp-Phe-D-Trp-Leu-Leu peptides, it was found that space-generating mutations in the deeper part of the receptor improved inverse agonism, whereas similar mutations located in the more extracellular part improved agonism. Modulation of the basal signaling by mutations in the receptor structure is primarily obtained by substitutions in an aromatic cluster that keep TMs VI and VII in close proximity to TM III and thus stabilize the active conformation. Also, substitution of a Phe in TM V is crucial for the high basal activity of the receptor as this residue serves as a partner for Trp VI:13 in the active conformation. It is suggested that inverse agonist and antagonist against the ghrelin receptor provide an interesting possibility in the development of drugs for treatment of obesity and

  2. Association of A-604G ghrelin gene polymorphism and serum ghrelin levels with the risk of obesity in a mexican population.

    Science.gov (United States)

    Llamas-Covarrubias, Iris Monserrat; Llamas-Covarrubias, Mara Anaís; Martinez-López, Erika; Zepeda-Carrillo, Eloy Alfonso; Rivera-León, Edgar Alfonso; Palmeros-Sánchez, Beatriz; Alcalá-Zermeño, Juan Luis; Sánchez-Enríquez, Sergio

    2017-07-01

    Obesity is a metabolic disorder that has a multifactorial etiology and affects millions of people worldwide. Ghrelin, a hormone coded by the GHRL gene, plays a role in human body composition and appetite. Single nucleotide polymorphisms (SNPs) of the GHRL gene have been associated with obesity and metabolic disorders. To evaluate the association of A-604G SNP of GHRL promoter region with serum ghrelin levels and the risk of obesity in a Mexican population. Two hundred and fifty individuals were enrolled and classified as obese or control subjects (CS) according to BMI. DNA samples, anthropometric measurements and biochemical parameters were obtained from all subjects. The A-604G SNP was genotyped using PCR-RFLPs technique. Ghrelin levels were measured using a commercial enzyme immunoassay. The G/G genotype was more frequent among obese individuals (p ghrelin levels were higher in obese patients (p = 0.004) than in CS, however, significance was lost after adjustment for age (p = 0.088). The G/G genotype was associated with higher levels of serum ghrelin (p = 0.02) independently of the effect of age. The G/G genotype of the A-604G SNP in the GHRL gene is associated with altered serum ghrelin levels and obesity. The A allele was also associated with protection against obesity in this study.

  3. Overlapping binding site for the endogenous agonist, small-molecule agonists, and ago-allosteric modulators on the ghrelin receptor

    DEFF Research Database (Denmark)

    Holst, Birgitte; Frimurer, Thomas M; Mokrosinski, Jacek

    2008-01-01

    A library of robust ghrelin receptor mutants with single substitutions at 22 positions in the main ligand-binding pocket was employed to map binding sites for six different agonists: two peptides (the 28-amino-acid octanoylated endogenous ligand ghrelin and the hexapeptide growth hormone......, and PheVI:23 on the opposing face of transmembrane domain (TM) VI. Each of the agonists was also affected selectively by specific mutations. The mutational map of the ability of L-692,429 and GHRP-6 to act as allosteric modulators by increasing ghrelin's maximal efficacy overlapped with the common....... It is concluded that although each of the ligands in addition exploits other parts of the receptor, a large, common binding site for both small-molecule agonists--including ago-allosteric modulators--and the endogenous agonist is found on the opposing faces of TM-III and -VI of the ghrelin receptor....

  4. Growth hormone-releasing hormone as an agonist of the ghrelin receptor GHS-R1a.

    Science.gov (United States)

    Casanueva, Felipe F; Camiña, Jesus P; Carreira, Marcos C; Pazos, Yolanda; Varga, Jozsef L; Schally, Andrew V

    2008-12-23

    Ghrelin synergizes with growth hormone-releasing hormone (GHRH) to potentiate growth hormone (GH) response through a mechanism not yet fully characterized. This study was conducted to analyze the role of GHRH as a potential ligand of the ghrelin receptor, GHS-R1a. The results show that hGHRH(1-29)NH(2) (GHRH) induces a dose-dependent calcium mobilization in HEK 293 cells stably transfected with GHS-R1a an effect not observed in wild-type HEK 293 cells. This calcium rise is also observed using the GHRH receptor agonists JI-34 and JI-36. Radioligand binding and cross-linking studies revealed that calcium response to GHRH is mediated by the ghrelin receptor GHS-R1a. GHRH activates the signaling route of inositol phosphate and potentiates the maximal response to ghrelin measured in inositol phosphate turnover. The presence of GHRH increases the binding capacity of (125)I-ghrelin in a dose dependent-fashion showing a positive binding cooperativity. In addition, confocal microscopy in CHO cells transfected with GHS-R1a tagged with enhanced green fluorescent protein shows that GHRH activates the GHS-R1a endocytosis. Furthermore, the selective GHRH-R antagonists, JV-1-42 and JMR-132, act also as antagonists of the ghrelin receptor GHS-R1a. Our findings suggest that GHRH interacts with ghrelin receptor GHS-R1a, and, in consequence, modifies the ghrelin-associated intracellular signaling pathway. This interaction may represent a form of regulation, which could play a putative role in the physiology of GH regulation and appetite control.

  5. Both acyl and des-acyl ghrelin regulate adiposity and glucose metabolism via central nervous system ghrelin receptors.

    Science.gov (United States)

    Heppner, Kristy M; Piechowski, Carolin L; Müller, Anne; Ottaway, Nickki; Sisley, Stephanie; Smiley, David L; Habegger, Kirk M; Pfluger, Paul T; Dimarchi, Richard; Biebermann, Heike; Tschöp, Matthias H; Sandoval, Darleen A; Perez-Tilve, Diego

    2014-01-01

    Growth hormone secretagogue receptors (GHSRs) in the central nervous system (CNS) mediate hyperphagia and adiposity induced by acyl ghrelin (AG). Evidence suggests that des-AG (dAG) has biological activity through GHSR-independent mechanisms. We combined in vitro and in vivo approaches to test possible GHSR-mediated biological activity of dAG. Both AG (100 nmol/L) and dAG (100 nmol/L) significantly increased inositol triphosphate formation in human embryonic kidney-293 cells transfected with human GHSR. As expected, intracerebroventricular infusion of AG in mice increased fat mass (FM), in comparison with the saline-infused controls. Intracerebroventricular dAG also increased FM at the highest dose tested (5 nmol/day). Chronic intracerebroventricular infusion of AG or dAG increased glucose-stimulated insulin secretion (GSIS). Subcutaneously infused AG regulated FM and GSIS in comparison with saline-infused control mice, whereas dAG failed to regulate these parameters even with doses that were efficacious when delivered intracerebroventricularly. Furthermore, intracerebroventricular dAG failed to regulate FM and induce hyperinsulinemia in GHSR-deficient (Ghsr(-/-)) mice. In addition, a hyperinsulinemic-euglycemic clamp suggests that intracerebroventricular dAG impairs glucose clearance without affecting endogenous glucose production. Together, these data demonstrate that dAG is an agonist of GHSR and regulates body adiposity and peripheral glucose metabolism through a CNS GHSR-dependent mechanism.

  6. Revised genomic structure of the human ghrelin gene and identification of novel exons, alternative splice variants and natural antisense transcripts

    Directory of Open Access Journals (Sweden)

    Herington Adrian C

    2007-08-01

    Full Text Available Abstract Background Ghrelin is a multifunctional peptide hormone expressed in a range of normal tissues and pathologies. It has been reported that the human ghrelin gene consists of five exons which span 5 kb of genomic DNA on chromosome 3 and includes a 20 bp non-coding first exon (20 bp exon 0. The availability of bioinformatic tools enabling comparative analysis and the finalisation of the human genome prompted us to re-examine the genomic structure of the ghrelin locus. Results We have demonstrated the presence of an additional novel exon (exon -1 and 5' extensions to exon 0 and 1 using comparative in silico analysis and have demonstrated their existence experimentally using RT-PCR and 5' RACE. A revised exon-intron structure demonstrates that the human ghrelin gene spans 7.2 kb and consists of six rather than five exons. Several ghrelin gene-derived splice forms were detected in a range of human tissues and cell lines. We have demonstrated ghrelin gene-derived mRNA transcripts that do not code for ghrelin, but instead may encode the C-terminal region of full-length preproghrelin (C-ghrelin, which contains the coding region for obestatin and a transcript encoding obestatin-only. Splice variants that differed in their 5' untranslated regions were also found, suggesting a role of these regions in the post-transcriptional regulation of preproghrelin translation. Finally, several natural antisense transcripts, termed ghrelinOS (ghrelin opposite strand transcripts, were demonstrated via orientation-specific RT-PCR, 5' RACE and in silico analysis of ESTs and cloned amplicons. Conclusion The sense and antisense alternative transcripts demonstrated in this study may function as non-coding regulatory RNA, or code for novel protein isoforms. This is the first demonstration of putative obestatin and C-ghrelin specific transcripts and these findings suggest that these ghrelin gene-derived peptides may also be produced independently of preproghrelin

  7. Apo-ghrelin receptor (apo-GHSR1a Regulates Dopamine Signaling in the Brain

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    Andras eKern

    2014-08-01

    Full Text Available The orexigenic peptide hormone ghrelin is synthesized in the stomach and its receptor growth hormone secretagogue receptor (GHSR1a is expressed mainly in the central nervous system (CNS. In this review we confine our discussion to the physiological role of GHSR1a in the brain. Paradoxically, despite broad expression of GHSR1a in the CNS, other than trace amounts in the hypothalamus, ghrelin is undetectable in the brain. In our efforts to elucidate the function of the ligand-free ghrelin receptor (apo-GHSR1a we identified subsets of neurons that co-express GHSR1a and dopamine receptors. In this review we focus on interactions between apo-GHSR1a and dopamine-2 receptor (DRD2 and formation of GHSR1a:DRD2 heteromers in hypothalamic neurons that regulate appetite, and discuss implications for the treatment of Prader-Willi syndrome. GHSR1a antagonists of distinct chemical structures, a quinazolinone and a triazole, respectively enhance and inhibit dopamine signaling through GHSR1a:DRD2 heteromers by an allosteric mechanism. This finding illustrates a potential strategy for designing the next generation of drugs for treating eating disorders as well as psychiatric disorders caused by abnormal dopamine signaling. Treatment with a GHSR1a antagonist that enhances dopamine/DRD2 activity in GHSR1a:DRD2 expressing hypothalamic neurons has the potential to inhibit the uncontrollable hyperphagia associated with Prader-Willi syndrome. DRD2 antagonists are prescribed for treating schizophrenia, but these block dopamine signaling in all DRD2 expressing neurons and are associated with adverse side effects, including enhanced appetite and excessive weight gain. A GHSR1a antagonist of structural class that allosterically blocks dopamine/DRD2 action in GHSR1a:DRD2 expressing neurons would have no effect on neurons expressing DRD2 alone; therefore, the side effects of DRD2 antagonists would potentially be reduced thereby enhancing patient compliance.

  8. Modulation of constitutive activity and signaling bias of the ghrelin receptor by conformational constraint in the second extracellular loop

    DEFF Research Database (Denmark)

    Mokrosinski, Jacek; Frimurer, Thomas M; Sivertsen, Bjoern

    2012-01-01

    Based on a rare, natural Glu for Ala204(C+6) variant located six residues after the conserved Cys residue in extracellular loop 2 (ECL2b) associated with selective elimination of the high constitutive signaling of the ghrelin receptor, this loop was subjected to a detailed structure functional....... Moreover, the constitutive activity of the receptor was inhibited by Zn(2+) binding in an engineered metal-ion site stabilizing an a-helical conformation of this loop segment. It is concluded that the high constitutive activity of the ghrelin receptor is dependent upon flexibility in the C-terminal segment...

  9. Polymorphisms in the ghrelin gene and their associations with milk yield and quality in water buffaloes.

    Science.gov (United States)

    Gil, F M M; de Camargo, G M F; Pablos de Souza, F R; Cardoso, D F; Fonseca, P D S; Zetouni, L; Braz, C U; Aspilcueta-Borquis, R R; Tonhati, H

    2013-05-01

    Ghrelin is a gastrointestinal hormone that acts in releasing growth hormone and influences the body general metabolism. It has been proposed as a candidate gene for traits such as growth, carcass quality, and milk production of livestock because it influences feed intake. In this context, the aim of this study was to verify the existence of polymorphisms in the ghrelin gene and their associations with milk, fat and protein yield, and percentage in water buffaloes (Bubalus bubalis). A group of 240 animals was studied. Five primer pairs were used and 11 single nucleotide polymorphisms (SNP) were found in the ghrelin gene by sequencing. The animals were genotyped for 8 SNP by PCR-RFLP. The SNP g.960G>A and g.778C>T were associated with fat yield and the SNP g.905T>C was associated with fat yield and percentage and protein percentage. These SNP are located in intronic regions of DNA and may be in noncoding RNA sites or affect transcriptional efciency. The ghrelin gene in buffaloes influences milk fat and protein synthesis. The polymorphisms observed can be used as molecular markers to assist selection. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  10. Central neuropeptide Y receptors are involved in 3rd ventricular ghrelin induced alteration of colonic transit time in conscious fed rats

    Directory of Open Access Journals (Sweden)

    Ritter Michael

    2005-02-01

    Full Text Available Abstract Background Feeding related peptides have been shown to be additionally involved in the central autonomic control of gastrointestinal functions. Recent studies have shown that ghrelin, a stomach-derived orexigenic peptide, is involved in the autonomic regulation of GI function besides feeding behavior. Pharmacological evidence indicates that ghrelin effects on food intake are mediated by neuropeptide Y in the central nervous system. Methods In the present study we examine the role of ghrelin in the central autonomic control of GI motility using intracerobroventricular and IP microinjections in a freely moving conscious rat model. Further the hypothesis that a functional relationship between NPY and ghrelin within the CNS exists was addressed. Results ICV injections of ghrelin (0.03 nmol, 0.3 nmol and 3.0 nmol/5 μl and saline controls decreased the colonic transit time up to 43%. IP injections of ghrelin (0.3 nmol – 3.0 nmol kg-1 BW and saline controls decreased colonic transit time dose related. Central administration of the NPY1 receptor antagonist, BIBP-3226, prior to centrally or peripherally administration of ghrelin antagonized the ghrelin induced stimulation of colonic transit. On the contrary ICV-pretreatment with the NPY2 receptor antagonist, BIIE-0246, failed to modulate the ghrelin induced stimulation of colonic motility. Conclusion The results suggest that ghrelin acts in the central nervous system to modulate gastrointestinal motor function utilizing NPY1 receptor dependent mechanisms.

  11. Ghrelin receptor expression and colocalization with anterior pituitary hormones using a GHSR-GFP mouse line.

    Science.gov (United States)

    Reichenbach, Alex; Steyn, Frederik J; Sleeman, Mark W; Andrews, Zane B

    2012-11-01

    Ghrelin is the endogenous ligand for the GH secretagogue receptor (GHSR) and robustly stimulates GH release from the anterior pituitary gland. Ghrelin also regulates the secretion of anterior pituitary hormones including TSH, LH, prolactin (PRL), and ACTH. However, the relative contribution of a direct action at the GHSR in the anterior pituitary gland vs. an indirect action at the GHSR in the hypothalamus remains undefined. We used a novel GHSR-enhanced green fluorescent protein (eGFP) reporter mouse to quantify GHSR coexpression with GH, TSH, LH, PRL, and ACTH anterior pituitary cells in males vs. females and in chow-fed or calorie-restricted (CR) mice. GHSR-eGFP-expressing cells were only observed in anterior pituitary. The number of GHSR-eGFP-expressing cells was higher in male compared with females, and CR did not affect the GHSR-eGFP cell number. Double staining revealed 77% of somatotrophs expressed GHSR-eGFP in both males and females. Nineteen percent and 12.6% of corticotrophs, 21% and 9% of lactotrophs, 18% and 19% of gonadotrophs, and 3% and 9% of males and females, respectively, expressed GHSR-eGFP. CR increased the number of TSH cells, but suppressed the number of lactotrophs and gonadotrophs, expressing GHSR-eGFP compared with controls. These studies support a robust stimulatory action of ghrelin via the GHSR on GH secretion and identify a previously unknown sexual dimorphism in the GHSR expression in the anterior pituitary. CR affects GHSR-eGFP expression on lactotrophs, gonadotrophs, and thyrotrophs, which may mediate reproductive function and energy metabolism during periods of negative energy balance. The low to moderate expression of GHSR-eGFP suggests that ghrelin plays a minor direct role on remaining anterior pituitary cells.

  12. Maternal serum ratio of ghrelin to obestatin decreased in preeclampsia.

    Science.gov (United States)

    Wu, Weiguang; Fan, Xiaobin; Yu, Yuecheng; Wang, Yingchun

    2015-10-01

    Ghrelin, an endogenous for the growth hormone secretagogue receptor, has been shown to participate in blood pressure regulation. Obestatin, encoded by the same gene as ghrelin, is described as a physiological opponent of ghrelin. We hypothesized that ghrelin/obestatin imbalance played a role in the pathogenesis. This study was designed to determine the alterations of ghrelin and obestatin concentrations and ghrelin/obestatin ratio in maternal serum in preeclampsia. This retrospective case-control study included 31 preeclampsia and 31 gestational week-matched normal pregnancies. Ghrelin and obestatin concentrations in maternal serum were determined by radioimmunoassay, and the ghrelin/obestatin ratio was calculated. The ghrelin concentration and ghrelin/obestatin ratio in maternal serum were significantly lower in preeclampsia than in normal pregnancies (214.34±14.27pg/mL vs 251.49±16.15pg/mL, P=0.041, 1.07±0.09 vs 0.82±0.08, P=0.023). The obestatin concentration in maternal serum was significantly higher in preeclampsia than in normal pregnancies (276.35±15.38pg/mL vs 223.53±18.61pg/mL, P=0.019). The systolic blood pressure in preeclampsia was negatively correlated with ghrelin concentration and ghrelin/obestatin ratio (r=-0.549, P=0.003; r=-0.491, P=0.004) and was positively correlated with obestatin concentrations in preeclampsia (r=0.388, P=0.013). The findings of this study suggested disturbance of ghrelin and obestatin in maternal serum in preeclampsia, and ghrelin/obestatin imbalance might play a role in the pathogenesis of preeclampsia. Copyright © 2015 International Society for the Study of Hypertension in Pregnancy. Published by Elsevier B.V. All rights reserved.

  13. Devil's Claw to suppress appetite--ghrelin receptor modulation potential of a Harpagophytum procumbens root extract.

    Directory of Open Access Journals (Sweden)

    Cristina Torres-Fuentes

    Full Text Available Ghrelin is a stomach-derived peptide that has been identified as the only circulating hunger hormone that exerts a potent orexigenic effect via activation of its receptor, the growth hormone secretagogue receptor (GHS-R1a. Hence, the ghrelinergic system represents a promising target to treat obesity and obesity-related diseases. In this study we analysed the GHS-R1a receptor activating potential of Harpagophytum procumbens, popularly known as Devil's Claw, and its effect on food intake in vivo. H. procumbens is an important traditional medicinal plant from Southern Africa with potent anti-inflammatory and analgesic effects. This plant has been also used as an appetite modulator but most evidences are anecdotal and to our knowledge, no clear scientific studies relating to appetite modulation have been done to this date. The ghrelin receptor activation potential of an extract derived from the dried tuberous roots of H. procumbens was analysed by calcium mobilization and receptor internalization assays in human embryonic kidney cells (Hek stably expressing the GHS-R1a receptor. Food intake was investigated in male C57BL/6 mice following intraperitoneal administration of H. procumbens root extract in ad libitum and food restricted conditions. Exposure to H. procumbens extract demonstrated a significant increased cellular calcium influx but did not induce subsequent GHS-R1a receptor internalization, which is a characteristic for full receptor activation. A significant anorexigenic effect was observed in male C57BL/6 mice following peripheral administration of H. procumbens extract. We conclude that H. procumbens root extract is a potential novel source for potent anti-obesity bioactives. These results reinforce the promising potential of natural bioactives to be developed into functional foods with weight-loss and weight maintenance benefits.

  14. Complex organisation and structure of the ghrelin antisense strand gene GHRLOS, a candidate non-coding RNA gene

    Directory of Open Access Journals (Sweden)

    Herington Adrian C

    2008-10-01

    Full Text Available Abstract Background The peptide hormone ghrelin has many important physiological and pathophysiological roles, including the stimulation of growth hormone (GH release, appetite regulation, gut motility and proliferation of cancer cells. We previously identified a gene on the opposite strand of the ghrelin gene, ghrelinOS (GHRLOS, which spans the promoter and untranslated regions of the ghrelin gene (GHRL. Here we further characterise GHRLOS. Results We have described GHRLOS mRNA isoforms that extend over 1.4 kb of the promoter region and 106 nucleotides of exon 4 of the ghrelin gene, GHRL. These GHRLOS transcripts initiate 4.8 kb downstream of the terminal exon 4 of GHRL and are present in the 3' untranslated exon of the adjacent gene TATDN2 (TatD DNase domain containing 2. Interestingly, we have also identified a putative non-coding TATDN2-GHRLOS chimaeric transcript, indicating that GHRLOS RNA biogenesis is extremely complex. Moreover, we have discovered that the 3' region of GHRLOS is also antisense, in a tail-to-tail fashion to a novel terminal exon of the neighbouring SEC13 gene, which is important in protein transport. Sequence analyses revealed that GHRLOS is riddled with stop codons, and that there is little nucleotide and amino-acid sequence conservation of the GHRLOS gene between vertebrates. The gene spans 44 kb on 3p25.3, is extensively spliced and harbours multiple variable exons. We have also investigated the expression of GHRLOS and found evidence of differential tissue expression. It is highly expressed in tissues which are emerging as major sites of non-coding RNA expression (the thymus, brain, and testis, as well as in the ovary and uterus. In contrast, very low levels were found in the stomach where sense, GHRL derived RNAs are highly expressed. Conclusion GHRLOS RNA transcripts display several distinctive features of non-coding (ncRNA genes, including 5' capping, polyadenylation, extensive splicing and short open reading

  15. A Novel Human Ghrelin Variant (In1-Ghrelin) and Ghrelin-O-Acyltransferase Are Overexpressed in Breast Cancer: Potential Pathophysiological Relevance

    Science.gov (United States)

    Gahete, Manuel D.; Córdoba-Chacón, José; Hergueta-Redondo, Marta; Martínez-Fuentes, Antonio J.; Kineman, Rhonda D.; Moreno-Bueno, Gema

    2011-01-01

    The human ghrelin gene, which encodes the ghrelin and obestatin peptides, contains 5 exons (Ex), with Ex1-Ex4 encoding a 117 amino-acid (aa) preproprotein that is known to be processed to yield a 28-aa (ghrelin) and/or a 23-aa (obestatin) mature peptides, which possess biological activities in multiple tissues. However, the ghrelin gene also encodes additional peptides through alternative splicing or post-translational modifications. Indeed, we previously identified a spliced mRNA ghrelin variant in mouse (In2-ghrelin-variant), which is regulated in a tissue-dependent manner by metabolic status and may thus be of biological relevance. Here, we have characterized a new human ghrelin variant that contains Ex0-1, intron (In) 1, and Ex2 and lacks Ex3-4. This human In1-ghrelin variant would encode a new prepropeptide that conserves the first 12aa of native-ghrelin (including the Ser3-potential octanoylation site) but has a different C-terminal tail. Expression of In1-variant was detected in 22 human tissues and its levels were positively correlated with those of ghrelin-O-acyltransferase (GOAT; p = 0.0001) but not with native-ghrelin expression, suggesting that In1-ghrelin could be a primary substrate for GOAT in human tissues. Interestingly, levels of In1-ghrelin variant expression in breast cancer samples were 8-times higher than those of normal mammary tissue, and showed a strong correlation in breast tumors with GOAT (p = 0.0001), ghrelin receptor-type 1b (GHSR1b; p = 0.049) and cyclin-D3 (a cell-cycle inducer/proliferation marker; p = 0.009), but not with native-ghrelin or GHSR1a expression. Interestingly, In1-ghrelin variant overexpression increased basal proliferation of MDA-MB-231 breast cancer cells. Taken together, our results provide evidence that In1-ghrelin is a novel element of the ghrelin family with a potential pathophysiological role in breast cancer. PMID:21829727

  16. Ghrelin Gene Variants Influence on Metabolic Syndrome Components in Aged Spanish Population.

    Science.gov (United States)

    Mora, Mireia; Adam, Victoria; Palomera, Elisabet; Blesa, Sebastian; Díaz, Gonzalo; Buquet, Xavier; Serra-Prat, Mateu; Martín-Escudero, Juan Carlos; Palanca, Ana; Chaves, Javier Felipe; Puig-Domingo, Manuel

    2015-01-01

    The role of genetic variations within the ghrelin gene on cardiometabolic profile and nutritional status is still not clear in humans, particularly in elderly people. We investigated six SNPs of the ghrelin gene and their relationship with metabolic syndrome (MS) components. 824 subjects (413 men/411 women, age 77.31±5.04) participating in the Mataró aging study (n = 310) and the Hortega study (n = 514) were analyzed. Anthropometric variables, ghrelin, lipids, glucose and blood pressure levels were measured, and distribution of SNPs -994CT (rs26312), -604GA (rs27647), -501AC (rs26802), R51Q (rs34911341), M72L (rs696217) and L90G (rs4684677) of the ghrelin gene evaluated. Genotypes were determined by multiplex PCR and SNaPshot minisequencing. MS (IDF criteria) was found in 54.9%. No association between any of the SNPs and levels of total fasting circulating ghrelin levels was found. C/A-A/A genotype of M72L was associated with increased risk of central obesity according to IDF criteria, while G/A-G/G genotypes of -604GA with reduced risk. A/A genotype of -501AC polymorphism was associated to decreased BMI. In relation to lipid profile, the same genotypes of -604GA were associated with increased total cholesterol and LDL-cholesterol and -501AC with reduced triglycerides. There were no associations with systolic or diastolic blood pressure levels or with hypertension, glucose levels or diabetes and ghrelin polymorphisms. However, G/G genotype of -604GA was associated with glucose >100 mg/dL. Haplotype analysis showed that only one haplotype is associated with increased risk of waist circumference and central obesity. The analysis of subjects by gender showed an important and different association of these polymorphisms regarding MS parameters. Ghrelin gene variants -604GA, -501AC and M72L are associated with certain components of MS, in particular to BMI and lipid profile in elderly Spanish subjects.

  17. Ghrelin Gene Variants Influence on Metabolic Syndrome Components in Aged Spanish Population.

    Directory of Open Access Journals (Sweden)

    Mireia Mora

    Full Text Available The role of genetic variations within the ghrelin gene on cardiometabolic profile and nutritional status is still not clear in humans, particularly in elderly people.We investigated six SNPs of the ghrelin gene and their relationship with metabolic syndrome (MS components.824 subjects (413 men/411 women, age 77.31±5.04 participating in the Mataró aging study (n = 310 and the Hortega study (n = 514 were analyzed. Anthropometric variables, ghrelin, lipids, glucose and blood pressure levels were measured, and distribution of SNPs -994CT (rs26312, -604GA (rs27647, -501AC (rs26802, R51Q (rs34911341, M72L (rs696217 and L90G (rs4684677 of the ghrelin gene evaluated. Genotypes were determined by multiplex PCR and SNaPshot minisequencing. MS (IDF criteria was found in 54.9%.No association between any of the SNPs and levels of total fasting circulating ghrelin levels was found. C/A-A/A genotype of M72L was associated with increased risk of central obesity according to IDF criteria, while G/A-G/G genotypes of -604GA with reduced risk. A/A genotype of -501AC polymorphism was associated to decreased BMI. In relation to lipid profile, the same genotypes of -604GA were associated with increased total cholesterol and LDL-cholesterol and -501AC with reduced triglycerides. There were no associations with systolic or diastolic blood pressure levels or with hypertension, glucose levels or diabetes and ghrelin polymorphisms. However, G/G genotype of -604GA was associated with glucose >100 mg/dL. Haplotype analysis showed that only one haplotype is associated with increased risk of waist circumference and central obesity. The analysis of subjects by gender showed an important and different association of these polymorphisms regarding MS parameters.Ghrelin gene variants -604GA, -501AC and M72L are associated with certain components of MS, in particular to BMI and lipid profile in elderly Spanish subjects.

  18. Association between ghrelin gene variations and blood pressure in subjects with impaired glucose tolerance.

    Science.gov (United States)

    Mager, Ursula; Kolehmainen, Marjukka; Lindström, Jaana; Eriksson, Johan G; Valle, Timo T; Hämäläinen, Helena; Ilanne-Parikka, Pirjo; Keinänen-Kiukaanniemi, Sirkka; Tuomilehto, Jaakko O; Pulkkinen, Leena; Uusitupa, Matti I

    2006-09-01

    Ghrelin is a gut-brain hormone, which stimulates food intake and controls energy balance. Recently, it has been shown that ghrelin may also play a role in the regulation of blood pressure (BP) by acting at the sympathetic nervous system. In the present study we genotyped six variants of the ghrelin gene and its promoter, and tested whether these single nucleotide polymorphisms (SNPs) were associated with BP levels in participants of the Finnish Diabetes Prevention Study. The Finnish Diabetes Prevention Study was a longitudinal study where 522 subjects with impaired glucose tolerance were randomized into either an intervention or control group. DNA was available from 507 subjects (mean body mass index [BMI] 31.2+/-4.5 kg/m2, age 55+/-7 years). All six SNPs were screened by the restriction fragment length polymorphism method. Subjects with the most common genotype combination of the following four SNPs, -604G/A, -501A/C, Leu72Met, and Gln90Leu, had the lowest systolic (131+/-11 v 137+/-13 mm Hg, P=.003) and diastolic BP levels (79+/-7 v 83+/-7 mm Hg, P=.004) at the baseline of the study and during 3 years of follow-up compared to all other genotypes. Adjustments for age, gender, antihypertensive medication, BMI, waist circumference, and alcohol intake did not change this association. Several ghrelin gene variations were associated with BP levels in subjects with impaired glucose tolerance.

  19. Leu72Met and Other Intronic Polymorphisms in the and Genes Are Not Associated with Type 2 Diabetes Mellitus, Insulin Resistance, or Serum Ghrelin Levels in a Saudi Population

    OpenAIRE

    Faris Elbahi Joatar; Ali Ahmed Al Qarni; Muhalab E. Ali; Abdulaziz Al Masaud; Abdirashid M. Shire; Nagalla Das; Khalid Gumaa; Hayder A. Giha

    2017-01-01

    Background Ghrelin (GHRL), a gastric peptide encoded by the GHRL gene, is known to be involved in energy homeostasis via its G protein receptor, encoded by the growth hormone secretagogue receptor (GHSR) gene. Some studies have shown associations between plasma GHRL levels and GHRL single-nucleotide polymorphisms (SNPs), namely the Leu72Met polymorphism (rs696217 TG), with type 2 diabetes mellitus (T2DM) and insulin resistance (IR), while others have not. The controversies in these associatio...

  20. G Protein and β-arrestin signaling bias at the ghrelin receptor.

    Science.gov (United States)

    Evron, Tama; Peterson, Sean M; Urs, Nikhil M; Bai, Yushi; Rochelle, Lauren K; Caron, Marc G; Barak, Larry S

    2014-11-28

    The G protein-coupled ghrelin receptor GHSR1a is a potential pharmacological target for treating obesity and addiction because of the critical role ghrelin plays in energy homeostasis and dopamine-dependent reward. GHSR1a enhances growth hormone release, appetite, and dopamine signaling through G(q/11), G(i/o), and G(12/13) as well as β-arrestin-based scaffolds. However, the contribution of individual G protein and β-arrestin pathways to the diverse physiological responses mediated by ghrelin remains unknown. To characterize whether a signaling bias occurs for GHSR1a, we investigated ghrelin signaling in a number of cell-based assays, including Ca(2+) mobilization, serum response factor response element, stress fiber formation, ERK1/2 phosphorylation, and β-arrestin translocation, utilizing intracellular second loop and C-tail mutants of GHSR1a. We observed that GHSR1a and β-arrestin rapidly form metastable plasma membrane complexes following exposure to an agonist, but replacement of the GHSR1a C-tail by the tail of the vasopressin 2 receptor greatly stabilizes them, producing complexes observable on the plasma membrane and also in endocytic vesicles. Mutations of the contiguous conserved amino acids Pro-148 and Leu-149 in the GHSR1a intracellular second loop generate receptors with a strong bias to G protein and β-arrestin, respectively, supporting a role for conformation-dependent signaling bias in the wild-type receptor. Our results demonstrate more balance in GHSR1a-mediated ERK signaling from G proteins and β-arrestin but uncover an important role for β-arrestin in RhoA activation and stress fiber formation. These findings suggest an avenue for modulating drug abuse-associated changes in synaptic plasticity via GHSR1a and indicate the development of GHSR1a-biased ligands as a promising strategy for selectively targeting downstream signaling events. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. Adaptive upregulation of gastric and hypothalamic ghrelin receptors and increased plasma ghrelin in a model of cancer chemotherapy-induced dyspepsia.

    Science.gov (United States)

    Malik, N M; Moore, G B T; Kaur, R; Liu, Y-L; Wood, S L; Morrow, R W; Sanger, G J; Andrews, P L R

    2008-06-05

    Chemotherapy treatment can lead to delayed gastric emptying, early satiety, anorexia, nausea and vomiting, described collectively as the cancer-associated dyspepsia syndrome (CADS). Administration of ghrelin (GHRL), an endogenous orexigenic peptide known to stimulate gastric motility, has been shown to reduce the symptoms of CADS induced in relevant animal models with the potent chemotherapeutic agent, cisplatin. We examined the effects in the rat of cisplatin (6 mg/kg i.p.) treatment on the expression of GHRL and ghrelin receptor (GHSR) mRNAs in the hypothalamus and the stomach at a time-point (2 days) when the effects of cisplatin are pronounced. In addition, plasma levels of GHRL (acylated and total including des-acyl GHRL) were measured and the effect on these levels of treatment with the synthetic glucocorticoid dexamethasone (2 mg/kg s.c. bd.) was investigated. Cisplatin increased GHSR mRNA expression in the stomach (67%) and hypothalamus (52%) but not GHRL mRNA expression and increased the percentage of acylated GHRL (7.03+/-1.35% vs. 11.38+/-2.40%) in the plasma. Dexamethasone reduced the plasma level of acylated GHRL and the percentage of acylated GHRL to values below those in animals treated with saline alone (7.03+/-1.35% vs. 2.60+/-0.49%). Our findings support the hypothesis that an adaptive upregulation of the ghrelin receptor may occur during cancer chemotherapy-associated dyspepsia. This may have a role in defensive responses to toxic challenges to the gut. In addition, our results provide preliminary evidence for glucocorticoid modulation of plasma ghrelin levels.

  2. [Relationship of Ghrelin gene polymorphism with congenital anorectal malformation and Hirschsprung disease].

    Science.gov (United States)

    Gao, Hong; Wang, Dajia; Zhao, Xiangxuan; Mi, Jie; Bai, Yuzuo; Wang, Weilin

    2015-07-01

    To explore the relationship of Ghrelin gene polymorphism with the occurrence of human anorectal malformations (ARMs) and Hirschsprung disease(HSCR). PCR and DNA sequencing were used to detect the single nucleotide polymorphism (SNPs) of 3 loci (rs139684563, rs149447194, rs186599567) genotype of Ghrelin gene in 100 children with ARMs, 100 children with HSCR, and 100 healthy children (normal group). Genovariation and gene mutation were analyzed with case-control method. Three loci SNPs were in accordance with Hardy-Weinberg genetic equilibrium. No significant differences were found in rs139684563 allele and genotype frequencies between the cases and the normal groups (P>0.05). The allele and genotype frequencies of rs149447194 and rs186599567 were significantly different between cases and normal group (Ppolymorphism changes may be associated with the pathogenesis of ARMs and HSCR.

  3. Association of Ghrelin Gene Polymorphisms and Serum Ghrelin Levels with the Risk of Hepatitis B Virus-Related Liver Diseases in a Chinese Population

    OpenAIRE

    Zhang, Xiaolian; Zhai, Limin; Rong, Chengzhi; Qin, Xue; Li, Shan

    2015-01-01

    Background The functions of ghrelin (GHRL) include anti-inflammatory effects, reduction of the fibrogenic response, protection of liver tissue, and regulation of cell proliferation. Genetic variations in the GHRL gene may play an important role in the development of chronic hepatitis B (CHB), liver cirrhosis (LC) and hepatocellular carcinoma (HCC). Therefore, we investigated whether GHRL gene polymorphisms and its serum levels are associated with hepatitis B virus (HBV)-related diseases risk ...

  4. Mechanisms of anorexia-cachexia syndrome and rational for treatment with selective ghrelin receptor agonist.

    Science.gov (United States)

    Esposito, Angela; Criscitiello, Carmen; Gelao, Lucia; Pravettoni, Gabriella; Locatelli, Marzia; Minchella, Ida; Di Leo, Maria; Liuzzi, Rita; Milani, Alessandra; Massaro, Mariangela; Curigliano, Giuseppe

    2015-11-01

    Cancer cachexia is a multi-organ, multifactorial and often irreversible syndrome affecting many patients with cancer. Cancer cachexia is invariably associated with weight loss, mainly from loss of skeletal muscle and body fat, conditioning a reduced quality of life due to asthenia, anorexia, anaemia and fatigue. Treatment options for treating cancer cachexia are limited. The approach is multimodal and may include: treatment of secondary gastrointestinal symptoms, nutritional treatments, drug, and non-drug treatments. Nutritional counselling and physical training may be beneficial in delaying or preventing the development of anorexia-cachexia. However, these interventions are limited in their effect, and no definitive pharmacological treatment is available to address the relevant components of the syndrome. Anamorelin is a first-in-class, orally active ghrelin receptor agonist that binds and stimulates the growth hormone secretagogue receptor centrally, thereby mimicking the appetite-enhancing and anabolic effects of ghrelin. It represents a new class of drug and an additional treatment option for this patient group, whose therapeutic options are currently limited. In this review we examine the mechanisms of anamorelin by which it contrasts catabolic states, its role in regulation of metabolism and energy homeostasis, the data of recent trials in the setting of cancer cachexia and its safety profile. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Identification of an efficacy switch region in the ghrelin receptor responsible for interchange between agonism and inverse agonism

    DEFF Research Database (Denmark)

    Holst, Birgitte; Mokrosinski, Jacek; Lang, Manja

    2007-01-01

    The carboxyamidated wFwLL peptide was used as a core ligand to probe the structural basis for agonism versus inverse agonism in the constitutively active ghrelin receptor. In the ligand, an efficacy switch could be built at the N terminus, as exemplified by AwFwLL, which functioned as a high...

  6. The proximal first exon architecture of the murine ghrelin gene is highly similar to its human orthologue

    Directory of Open Access Journals (Sweden)

    Seim Inge

    2009-05-01

    Full Text Available Abstract Background The murine ghrelin gene (Ghrl, originally sequenced from stomach tissue, contains five exons and a single transcription start site in a short, 19 bp first exon (exon 0. We recently isolated several novel first exons of the human ghrelin gene and found evidence of a complex transcriptional repertoire. In this report, we examined the 5' exons of the murine ghrelin orthologue in a range of tissues using 5' RACE. Findings 5' RACE revealed two transcription start sites (TSSs in exon 0 and four TSSs in intron 0, which correspond to 5' extensions of exon 1. Using quantitative, real-time RT-PCR (qRT-PCR, we demonstrated that extended exon 1 containing Ghrl transcripts are largely confined to the spleen, adrenal gland, stomach, and skin. Conclusion We demonstrate that multiple transcription start sites are present in exon 0 and an extended exon 1 of the murine ghrelin gene, similar to the proximal first exon organisation of its human orthologue. The identification of several transcription start sites in intron 0 of mouse ghrelin (resulting in an extension of exon 1 raises the possibility that developmental-, cell- and tissue-specific Ghrl mRNA species are created by employing alternative promoters and further studies of the murine ghrelin gene are warranted.

  7. Circulating ghrelin, leptin, and soluble leptin receptor concentrations and cardiometabolic risk factors in a community-based sample.

    Science.gov (United States)

    Ingelsson, Erik; Larson, Martin G; Yin, Xiaoyan; Wang, Thomas J; Meigs, James B; Lipinska, Izabella; Benjamin, Emelia J; Keaney, John F; Vasan, Ramachandran S

    2008-08-01

    The conjoint effects and relative importance of ghrelin, leptin, and soluble leptin receptor (sOB-R), adipokines involved in appetite control and energy expenditure in mediating cardiometabolic risk, is unknown. The objective of the study was to study the cross-sectional relations of these adipokines to cardiometabolic risk factors in a community-based sample. We measured circulating ghrelin, leptin, and sOB-R in 362 participants (mean age 45 yr; 54% women) of the Framingham Third Generation Cohort. Body mass index, waist circumference (WC), blood pressure, lipid measures, fasting glucose, smoking, and metabolic syndrome (MetS) were measured. Ghrelin and leptin concentrations were significantly higher in women (P risk.

  8. Development of Fluorinated Non-Peptidic Ghrelin Receptor Ligands for Potential Use in Molecular Imaging

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    Rareş-Petru Moldovan

    2017-04-01

    Full Text Available The ghrelin receptor (GhrR is a widely investigated target in several diseases. However, the current knowledge of its role and distribution in the brain is limited. Recently, the small and non-peptidic compound (S-6-(4-bromo-2-fluorophenoxy-3-((1-isopropylpiperidin-3-ylmethyl-2-methylpyrido[3,2-d]pyrimidin-4(3H-one ((S-9 has been described as a GhrR ligand with high binding affinity. Here, we describe the synthesis of fluorinated derivatives, the in vitro evaluation of their potency as partial agonists and selectivity at GhrRs, and their physicochemical properties. These results identified compounds (S-9, (R-9, and (S-16 as suitable parent molecules for 18F-labeled positron emission tomography (PET radiotracers to enable future investigation of GhrR in the brain.

  9. Opposite Regulation of Ghrelin and Glucagon-like Peptide-1 by Metabolite G-Protein-Coupled Receptors

    DEFF Research Database (Denmark)

    Engelstoft, M S; Schwartz, T W

    2016-01-01

    Gut hormones send information about incoming nutrients to the rest of the body and thereby control many aspects of metabolism. The secretion of ghrelin and glucagon-like protein (GLP)-1, two hormones with opposite secretory patterns and opposite actions on multiple targets, is controlled by a lim......Gut hormones send information about incoming nutrients to the rest of the body and thereby control many aspects of metabolism. The secretion of ghrelin and glucagon-like protein (GLP)-1, two hormones with opposite secretory patterns and opposite actions on multiple targets, is controlled...... by a limited number of G-protein coupled receptors (GPCRs); half of which recognize and bind dietary nutrient metabolites, metabolites generated by gut microbiota, and metabolites of the host's intermediary metabolism. Most metabolite GPCRs controlling ghrelin secretion are inhibitory, whereas all metabolite...... receptors controlling GLP-1 secretion are stimulatory. This dichotomy in metabolite sensor function, which is obtained through a combination of differential expression and cell-dependent signaling bias, offers pharmacological targets to stimulate GLP-1 and inhibit ghrelin through the same mechanism....

  10. Modulation of ingestive behavior and gastrointestinal motility by ghrelin in diabetic animals and humans.

    Science.gov (United States)

    Chen, Chih-Yen; Fujimiya, Mineko; Laviano, Alessandro; Chang, Full-Young; Lin, Han-Chieh; Lee, Shou-Dong

    2010-05-01

    Acyl ghrelin, a 28-amino acid peptide hormone, is the endogenous cognate ligand for the growth hormone secretagogue receptor. Ghrelin is involved in stimulating growth hormone release, eliciting feeding behavior, inducing adiposity and stimulating gastrointestinal motility. Ghrelin is unique for its post-translational modification of O-n-octanoylation at serine 3 through ghrelin O-acyltransferase, and is the only peripheral signal to enhance food intake. Plasma ghrelin levels manifest "biphasic changes" in diabetes mellitus (DM). In the early stage of DM, the stomach significantly increases the secretion of ghrelin into the plasma, and elevated plasma ghrelin levels are correlated with diabetic hyperphagic feeding and accelerated gastrointestinal motility. In the late stage of DM, plasma ghrelin levels may be lower, which might be linked with anorexia/muscle wasting, delayed gastrointestinal transit, and even gastroparesis. Therefore, the unique ghrelin system may be the most important player compared to the other hindgut hormones participating in the "entero-insular axis". Further studies using either knockdown or knockout of ghrelin gene products and ghrelin O-acyltransferase may unravel the pathogenesis of DM, and show benefits in combating this disease and metabolic syndrome. Copyright 2010 Elsevier. Published by Elsevier B.V. All rights reserved.

  11. Modulation of Ingestive Behavior and Gastrointestinal Motility by Ghrelin in Diabetic Animals and Humans

    Directory of Open Access Journals (Sweden)

    Chih-Yen Chen

    2010-05-01

    Full Text Available Acyl ghrelin, a 28-amino acid peptide hormone, is the endogenous cognate ligand for the growth hormone secretagogue receptor. Ghrelin is involved in stimulating growth hormone release, eliciting feeding behavior, inducing adiposity and stimulating gastrointestinal motility. Ghrelin is unique for its post-translational modification of O-n-octanoylation at serine 3 through ghrelin O-acyltransferase, and is the only peripheral signal to enhance food intake. Plasma ghrelin levels manifest “biphasic changes” in diabetes mellitus (DM. In the early stage of DM, the stomach significantly increases the secretion of ghrelin into the plasma, and elevated plasma ghrelin levels are correlated with diabetic hyperphagic feeding and accelerated gastrointestinal motility. In the late stage of DM, plasma ghrelin levels may be lower, which might be linked with anorexia/muscle wasting, delayed gastrointestinal transit, and even gastroparesis. Therefore, the unique ghrelin system may be the most important player compared to the other hindgut hormones participating in the “entero-insular axis”. Further studies using either knockdown or knockout of ghrelin gene products and ghrelin O-acyltransferase may unravel the pathogenesis of DM, and show benefits in combating this disease and metabolic syndrome.

  12. Ghrelin: ghrelin as a regulatory Peptide in growth hormone secretion.

    Science.gov (United States)

    Khatib, Nazli; Gaidhane, Shilpa; Gaidhane, Abhay M; Khatib, Mahanaaz; Simkhada, Padam; Gode, Dilip; Zahiruddin, Quazi Syed

    2014-08-01

    Ghrelin is a type of growth hormone (GH) secretagogue that stimulates the release of GH. It is a first hormone linking gastrointestinal-pituitary axis. This review highlights the interaction of ghrelin with GHRH and somatostatin to regulate the secretion of GH and intends to explore the possible physiological role of the ghrelin-pituitary-GH axis linkage system. Ghrelin is highly conserved among species and is classified into octanoylated (C8:0), decanoylated (C10:0), decenoylated (C10:1) and nonacylated,ghrelin. Acylated ghrelin is the major active form of human ghrelin. The primary production site of ghrelin is the stomach, and it interacts with stomach ghrelin as well as hypothalamic GHRH and somatostatin in the regulation of pituitary GH secretion. Ghrelin stimulate GH release through the GHS receptor to increase intracellular Ca2+ ([Ca2+] levels via IP3 signal transduction pathway. Ghrelin is a specific endogenous ligand for the GHS receptor and provides a definitive proof of the occurance of a GHS-GHS receptor signalling system in the regulation of GH secretion. Studies suggests that ghrelin is a powerful pharmacological agent that exerts a potent, time-dependent stimulation of pulsatile secretion of GH.

  13. No association of the Arg51Gln and Leu72Met polymorphisms of the ghrelin gene and polycystic ovary syndrome.

    Science.gov (United States)

    Wang, Kehua; Wang, Leiguang; Zhao, Yueran; Shi, Yuhua; Wang, Laicheng; Chen, Zi-Jiang

    2009-02-01

    Ghrelin plays a role in regulating glucose metabolism and energy balance. Polymorphisms in preproghrelin and ghrelin gene could be responsible for obesity, insulin resistance and low ghrelin levels observed in some individuals. The objective of this study was to evaluate the influence of two single-nucleotide polymorphisms (SNPs) of ghrelin gene on the clinical, the hormonal and metabolic features in women with polycystic ovary syndrome (PCOS) in a Chinese population. A large sample of Chinese PCOS (n = 271) women and a control group (n = 296) of healthy women matched for age were studied. Hormone and metabolic profiles were measured and blood samples were collected for genotype and allelic frequency analysis. Non-synonymous SNPs in the coding region (exon 2) of the preproghrelin gene (Arg51Gln (346 G>A) and Leu72Met (408 C>A) were studied using PCR and restriction fragment length polymorphism analysis. The polymorphism Arg51Gln was not found in the cohorts studied. The distribution of Leu72Met was similar in PCOS group and in healthy controls. There was no significant difference in age, BMI, waist-hip-ratio and levels of FSH, LH, estradiol, testosterone and prolactin between PCOS patients with different genotypes, and the level of plasma glucose and insulin was also similar. No association was found between Leu72Met and Arg51Gln polymorphisms in the ghrelin gene and PCOS in Chinese population.

  14. Expression and localization of ghrelin and its functional receptor in corpus luteum during different stages of estrous cycle and the modulatory role of ghrelin on progesterone production in cultured luteal cells in buffalo.

    Science.gov (United States)

    Gupta, M; Dangi, S S; Chouhan, V S; Hyder, I; Babitha, V; Yadav, V P; Khan, F A; Sonwane, A; Singh, G; Das, G K; Mitra, A; Bag, S; Sarkar, M

    2014-07-01

    Evidence obtained during recent years provided has insight into the regulation of corpus luteum (CL) development, function, and regression by locally produced ghrelin. The present study was carried out to evaluate the expression and localization of ghrelin and its receptor (GHS-R1a) in bubaline CL during different stages of the estrous cycle and investigate the role of ghrelin on progesterone (P4) production along with messenger RNA (mRNA) expression of P4 synthesis intermediates. The mRNA and protein expression of ghrelin and GHS-R1a was significantly greater in mid- and late luteal phases. Both factors were localized in luteal cells, exclusively in the cytoplasm. Immunoreactivity of ghrelin and GHS-R1a was greater during mid- and late luteal phases. Luteal cells were cultured in vitro and treated with ghrelin each at 1, 10, and 100 ng/mL concentrations for 48 h after obtaining 75% to 80% confluence. At a dose of 1 ng/mL, there was no significant difference in P4 secretion between control and treatment group. At 10 and 100 ng/mL, there was a decrease (P production in buffalo. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Polymorphisms for ghrelin with consequences on satiety and metabolic alterations.

    Science.gov (United States)

    Perret, Jason; De Vriese, Carine; Delporte, Christine

    2014-07-01

    To understand the current trend of ghrelin genetic variations on the control of satiety, eating behaviours, obesity, and metabolic alterations, and its development over the last 18 months. Several polymorphisms of the ghrelin gene, its receptor gene and ghrelin's acylating enzyme, ghrelin O-acyl transferase, have been identified and studied over the last decade in relation to control of satiety, obesity, eating behaviours, metabolic syndrome, glucose homeostasis, and type 2 diabetes. However, the effects described are either small or nonsignificant and often subjected to contradictory conclusions between studies. In the last 18 months, several of these areas of investigations have been revisited under more controlled conditions or have been subjected to meta-analysis. The effects of ghrelin gene polymorphism, is a complex area of investigation, due to ghrelin's interplay with a host of various factors part of an integrative network. However, taken together, results suggest that there are no or nonsignificant effects of the common genetic variants. A better understanding of the network, probably by a systems biology type approach, will be necessary to assign the exact role played by gene polymorphism of the component of the ghrelin axis.

  16. Ghrelin receptor antagonism attenuates cocaine- and amphetamine-induced locomotor stimulation, accumbal dopamine release, and conditioned place preference.

    Science.gov (United States)

    Jerlhag, Elisabet; Egecioglu, Emil; Dickson, Suzanne L; Engel, Jörgen A

    2010-09-01

    Recently we demonstrated that genetic or pharmacological suppression of the central ghrelin signaling system, involving the growth hormone secretagogue receptor 1A (GHS-R1A), lead to a reduced reward profile from alcohol. As the target circuits for ghrelin in the brain include a mesolimbic reward pathway that is intimately associated with reward-seeking behaviour, we sought to determine whether the central ghrelin signaling system is required for reward from drugs of abuse other than alcohol, namely cocaine or amphetamine. We found that amphetamine-as well as cocaine-induced locomotor stimulation and accumbal dopamine release were reduced in mice treated with a GHS-R1A antagonist. Moreover, the ability of these drugs to condition a place preference was also attenuated by the GHS-R1A antagonist. Thus GHS-R1A appears to be required not only for alcohol-induced reward, but also for reward induced by psychostimulant drugs. Our data suggest that the central ghrelin signaling system constitutes a novel potential target for treatment of addictive behaviours such as drug dependence.

  17. Genetic polymorphisms and protein structures in growth hormone, growth hormone receptor, ghrelin, insulin-like growth factor 1 and leptin in Mehraban sheep.

    Science.gov (United States)

    Bahrami, A; Behzadi, Sh; Miraei-Ashtiani, S R; Roh, S-G; Katoh, K

    2013-09-15

    The somatotropic axis, the control system for growth hormone (GH) secretion and its endogenous factors involved in the regulation of metabolism and energy partitioning, has promising potentials for producing economically valuable traits in farm animals. Here we investigated single nucleotide polymorphisms (SNPs) of the genes of factors involved in the somatotropic axis for growth hormone (GH1), growth hormone receptor (GHR), ghrelin (GHRL), insulin-like growth factor 1 (IGF-I) and leptin (LEP), using polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and DNA sequencing methods in 452 individual Mehraban sheep. A nonradioactive method to allow SSCP detection was used for genomic DNA and PCR amplification of six fragments: exons 4 and 5 of GH1; exon 10 of GH receptor (GHR); exon 1 of ghrelin (GHRL); exon 1 of insulin-like growth factor-I (IGF-I), and exon 3 of leptin (LEP). Polymorphisms were detected in five of the six PCR products. Two electrophoretic patterns were detected for GH1 exon 4. Five conformational patterns were detected for GH1 exon 5 and LEP exon 3, and three for IGF-I exon 1. Only GHR and GHRL were monomorphic. Changes in protein structures due to variable SNPs were also analyzed. The results suggest that Mehraban sheep, a major breed that is important for the animal industry in Middle East countries, has high genetic variability, opening interesting prospects for future selection programs and preservation strategies. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Effect of ghrelin receptor agonist and antagonist on the activity of arcuate nucleus tyrosine hydroxylase containing neurons in C57BL/6 male mice exposed to normal or high fat diet

    Czech Academy of Sciences Publication Activity Database

    Pirník, Z.; Majerčíková, Z.; Holubová, Martina; Pirník, R.; Železná, Blanka; Maletínská, Lenka; Kiss, A.

    2014-01-01

    Roč. 65, č. 4 (2014), s. 477-486 ISSN 0867-5910 Institutional support: RVO:61388963 Keywords : growth hormone secretagogue receptor * ghrelin receptor agonist * ghrelin receptor antagonist * high fat diet * tyrosine hydroxylase * arcuate nucleus * food intake Subject RIV: CE - Biochemistry Impact factor: 2.386, year: 2014

  19. Effects of ghrelin gene genotypes on the growth traits in Chinese cattle.

    Science.gov (United States)

    Zhang, Ai-ling; Zhang, Li; Zhang, Liang-zhi; Zhang, Cun-fang; Lan, Xian-yong; Zhang, Chun-lei; Chen, Hong

    2012-06-01

    Ghrelin is an important peptide that stimulates food intake and regulates energy balance of animals. Single nucleotide polymorphisms of ghrelin gene in three Chinese cattle populations were investigated through PCR-SSCP and DNA sequencing. Five over-lapped DNA fragments were analyzed and a total of three ones exhibited different genotypes. Three genotypes and four SNPs (-415 A > G, -414 T > C, -321 C > A, and -172 A > G) were found on the -544 to +35 bp region (G-1) of ghrelin gene. On the locus of -1037 to -509 bp (G-2), two genotypes and one SNP (-726 A > T) were discovered. And in the exon1, exon2, and intron1 (G-4 locus, (+4 to +427)), two genotypes and one SNP were detected (+205 C > T, located in intron1). Positions of the five SNPs in the 5′ regulatory region might be the transcription factor binding sites. The SNPs at -415 and -414 in the core binding sequence were found to cause the change of the site. Though the SNP at -172 did not change the binding site, it generated one new site at the same time. The frequencies of the genotypes varied differently in the three breeds. Results of ANOVA showed that G-1 was correlative to the ischium width (IW) of Nanyang cattle aged 18 months (p = 0.043). The least square analysis between genotypes at G-1 locus and growth traits in Nanyang cattle showed that the individuals (aged 18 months) with C genotype had greater IW than that of the other two genotypes. The C genotype might serve as one potential candidate genetic marker for cattle growth and development.

  20. Ghrelin, food intake, and botanical extracts: A Review.

    Science.gov (United States)

    Rezaie, Peyman; Mazidi, Mohsen; Nematy, Mohsen

    2015-01-01

    A kind of growth hormone secretagogue (GHS), ghrelin, was first isolated from the rat stomach and plays a major role in the activation of the growth hormone secretagogue receptor 1a (GHS-R1a) resulting the release of growth hormone (GH). The preproghrelin gene is placed on chromosome 3, at locus 3p25 -2 in humans and constitutes five exons and three introns. Ghrelin is most plentifully expressed in particular cells in the oxyntic glands of the gastric epithelium, initially named X/A-like cells. Almost 60-70% of circulating ghrelin is secreted by the stomach. Plasma ghrelin concentration alters throughout the day. Ghrelin has been suggested to act as a meal initiator because of its appetite-stimulating influences in free feeding rats in short period. In addition to ghrelin's function as a meal motivator, it seems to contribute in long-term energy balance and nutritional status. In addition, many studies have been carried out in order to investigate the effects of natural and medicinal plants and botanical extracts on appetite, food intake, energy hemostasis, and the level of related hormones including ghrelin. Due to the importance of ghrelin in nutritional and medical sciences, this review was performed to understand new aspects of this hormone's function.

  1. Orexin A/Hypocretin Modulates Leptin Receptor-Mediated Signaling by Allosteric Modulations Mediated by the Ghrelin GHS-R1A Receptor in Hypothalamic Neurons.

    Science.gov (United States)

    Medrano, Mireia; Aguinaga, David; Reyes-Resina, Irene; Canela, Enric I; Mallol, Josefa; Navarro, Gemma; Franco, Rafael

    2018-06-01

    The hypothalamus is a key integrator of nutrient-seeking signals in the form of hormones and metabolites originated in both the central nervous system and the periphery. The main autocrine and paracrine target of orexinergic-related hormones such as leptin, orexin/hypocretin, and ghrelin are neuropeptide Y neurons located in the arcuate nucleus of the hypothalamus. The aim of this study was to investigate the expression and the molecular and functional relationships between leptin, orexin/hypocretin and ghrelin receptors. Biophysical studies in a heterologous system showed physical interactions between them, with potential formation of heterotrimeric complexes. Functional assays showed robust allosteric interactions particularly different when the three receptors are expressed together. Further biochemical and pharmacological assays provided evidence of heterotrimer functional expression in primary cultures of hypothalamic neurons. These findings constitute evidence of close relationships in the action of the three hormones already starting at the receptor level in hypothalamic cells.

  2. Ghrelin: much more than a hunger hormone

    Science.gov (United States)

    Ghrelin is a multifaceted gut hormone that activates its receptor, growth hormone secretagogue receptor (GHS-R). Ghrelin's hallmark functions are its stimulatory effects on growth hormone release, food intake and fat deposition. Ghrelin is famously known as the 'hunger hormone'. However, ample recen...

  3. Lack of association of ghrelin precursor gene variants and percentage body fat or serum lipid profiles.

    Science.gov (United States)

    Martin, Glynn R; Loredo, J C; Sun, Guang

    2008-04-01

    Ghrelin has been recognized for its involvement in food intake, control of energy homeostasis, and lipid metabolism. However, the roles of genetic variations in the ghrelin precursor gene (GHRL) on body compositions and serum lipids are not clear in humans. Our study investigated five single-nucleotide polymorphisms (SNPs) within GHRL to determine their relationship with body fat percentage (BF), trunk fat percentage (TF), lower body (legs) fat percentage (LF), and serum lipids in 1,464 subjects, which were recruited from the genetically homogeneous population of Newfoundland and Labrador (NL), Canada. Serum glucose, insulin, total cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, and triglycerides were determined. Five SNPs are rs35684 (A/G: a transition substitution in exon 1), rs4684677 (A/T: a missense mutation), rs2075356 (C/T: intron), rs26802 (G/T: intron), and rs26311 (A/G: near the 3' untranslated region) of GHRL were genotyped using TaqMan validated or functionally tested SNP genotyping assays. Our study found no significant evidence of an allele or genotype association between any of the variant sites and body compositions or serum lipids. Furthermore, haplotype frequencies were not found to be significantly different between lean and obese subjects. In summary, the results of our study do not support a significant role for genetic variations in GHRL in the differences of body fat and serum lipid profiles in the NL population.

  4. Metabolic Benefit of Chronic Caloric Restriction and Activation of Hypothalamic AGRP/NPY Neurons in Male Mice Is Independent of Ghrelin

    Science.gov (United States)

    Rogers, Nicole H.; Walsh, Heidi; Alvarez-Garcia, Oscar; Park, Seongjoon; Gaylinn, Bruce; Thorner, Michael O.

    2016-01-01

    Aging is associated with attenuated ghrelin signaling. During aging, chronic caloric restriction (CR) produces health benefits accompanied by enhanced ghrelin production. Ghrelin receptor (GH secretagogue receptor 1a) agonists administered to aging rodents and humans restore the young adult phenotype; therefore, we tested the hypothesis that the metabolic benefits of CR are mediated by endogenous ghrelin. Three month-old male mice lacking ghrelin (Ghrelin−/−) or ghrelin receptor (Ghsr−/−), and their wild-type (WT) littermates were randomly assigned to 2 groups: ad libitum (AL) fed and CR, where 40% food restriction was introduced gradually to allow Ghrelin−/− and Ghsr−/− mice to metabolically adapt and avoid severe hypoglycemia. Twelve months later, plasma ghrelin, metabolic parameters, ambulatory activity, hypothalamic and liver gene expression, as well as body composition were measured. CR increased plasma ghrelin and des-acyl ghrelin concentrations in WT and Ghsr−/− mice. CR of WT, Ghsr−/−, and Ghrelin−/− mice markedly improved metabolic flexibility, enhanced ambulatory activity, and reduced adiposity. Inactivation of Ghrelin or Ghsr had no effect on AL food intake or food anticipatory behavior. In contrast to the widely held belief that endogenous ghrelin regulates food intake, CR increased expression of hypothalamic Agrp and Npy, with reduced expression of Pomc across genotypes. In the AL context, ablation of ghrelin signaling markedly inhibited liver steatosis, which correlated with reduced Pparγ expression and enhanced Irs2 expression. Although CR and administration of GH secretagogue receptor 1a agonists both benefit the aging phenotype, we conclude the benefits of chronic CR are a consequence of enhanced metabolic flexibility independent of endogenous ghrelin or des-acyl ghrelin signaling. PMID:26812158

  5. Ghrelin upregulates the phosphorylation of the GluN2B subunit of the NMDA receptor by activating GHSR1a and Fyn in the rat hippocampus.

    Science.gov (United States)

    Berrout, Liza; Isokawa, Masako

    2018-01-01

    Ghrelin and its receptor GHSR1a have been shown to exert numerous physiological functions in the brain, in addition to the well-established orexigenic role in the hypothalamus. Earlier work indicated that ghrelin stimulated the phosphorylation of the GluN1 subunit of the NMDA receptor (NMDAR) and enhanced synaptic transmission in the hippocampus. In the present study, we report that the exogenous application of ghrelin increased GluN2B phosphorylation. This increase was independent of GluN2B subunit activity or NMDAR channel activity. However, it depended on the activation of GHSR1a and Fyn as it was blocked by D-Lys3-GHRP-6 and PP2, respectively. Inhibitors for G-protein-regulated second messengers, such as Rp-cAMP, H89, TBB, ryanodine, and thapsigargin, unexpectedly enhanced GluN2B phosphorylation, suggesting that cAMP, PKA, casein kinase II, and cytosolic calcium signaling may oppose to the effect of ghrelin on the phosphorylation of GluN2B. Our findings suggest that 1) GluN2B is likely a molecular target of ghrelin and GHSR1a-driven signaling cascades, and 2) the ghrelin-mediated phosphorylation of GluN2B depends on Fyn activation under complex negative regulation by other second messengers. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Ghrelin receptor regulates appetite and satiety during aging in mice by regulating meal frequency and portion size but not total food intake

    Science.gov (United States)

    Aging is often associated with overweight and obesity. There exists a long-standing debate about whether meal pattern also contributes to the development of obesity. The orexigenic hormone ghrelin regulates appetite and satiety by activating its receptor, growth hormone secretagogue receptor (GHS-R)...

  7. Ghrelin receptor antagonism of morphine-induced conditioned place preference and behavioral and accumbens dopaminergic sensitization in rats.

    Science.gov (United States)

    Jerabek, Pavel; Havlickova, Tereza; Puskina, Nina; Charalambous, Chrysostomos; Lapka, Marek; Kacer, Petr; Sustkova-Fiserova, Magdalena

    2017-11-01

    An increasing number of studies over the past few years have demonstrated ghrelin's role in alcohol, cocaine and nicotine abuse. However, the role of ghrelin in opioid effects has rarely been examined. Recently we substantiated in rats that ghrelin growth hormone secretagogue receptors (GHS-R1A) appear to be involved in acute opioid-induced changes in the mesolimbic dopaminergic system associated with the reward processing. The aim of the present study was to ascertain whether a ghrelin antagonist (JMV2959) was able to inhibit morphine-induced biased conditioned place preference and challenge-morphine-induced accumbens dopaminergic sensitization and behavioral sensitization in adult male rats. In the place preference model, the rats were conditioned for 8 days with morphine (10 mg/kg s.c.). On the experimental day, JMV2959 (3 and 6 mg/kg i.p.) or saline were administered before testing. We used in vivo microdialysis to determine changes of dopamine and its metabolites in the nucleus accumbens in rats following challenge-morphine dose (5 mg/kg s.c.) with or without JMV2959 (3 and 6 mg/kg i.p.) pretreatment, administered on the 12th day of spontaneous abstinence from morphine repeated treatment (5 days, 10-40 mg/kg). Induced behavioral changes were simultaneously monitored. Pretreatment with JMV2959 significantly and dose dependently reduced the morphine-induced conditioned place preference and significantly and dose dependently reduced the challenge-morphine-induced dopaminergic sensitization and affected concentration of by-products associated with dopamine metabolism in the nucleus accumbens. JMV2959 pretreatment also significantly reduced challenge-morphine-induced behavioral sensitization. Our present data suggest that GHS-R1A antagonists deserve to be further investigated as a novel treatment strategy for opioid addiction. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. The oncogenic role of the In1-ghrelin splicing variant in prostate cancer aggressiveness.

    Science.gov (United States)

    Hormaechea-Agulla, Daniel; Gahete, Manuel D; Jiménez-Vacas, Juan M; Gómez-Gómez, Enrique; Ibáñez-Costa, Alejandro; L-López, Fernando; Rivero-Cortés, Esther; Sarmento-Cabral, André; Valero-Rosa, José; Carrasco-Valiente, Julia; Sánchez-Sánchez, Rafael; Ortega-Salas, Rosa; Moreno, María M; Tsomaia, Natia; Swanson, Steve M; Culler, Michael D; Requena, María J; Castaño, Justo P; Luque, Raúl M

    2017-08-29

    The Ghrelin-system is a complex, pleiotropic family composed of several peptides, including native-ghrelin and its In1-ghrelin splicing variant, and receptors (GHSR 1a/b), which are dysregulated in various endocrine-related tumors, where they associate to pathophysiological features, but the presence, functional role, and mechanisms of actions of In1-ghrelin splicing variant in prostate-cancer (PCa), is completely unexplored. Herein, we aimed to determine the presence of key ghrelin-system components (native-ghrelin, In1-ghrelin, GHSR1a/1b) and their potential pathophysiological role in prostate cancer (PCa). In1-ghrelin and native-ghrelin expression was evaluated by qPCR in prostate tissues from patients with high PCa-risk (n = 52; fresh-tumoral biopsies), and healthy-prostates (n = 12; from cystoprostatectomies) and correlated with clinical parameters using Spearman-test. In addition, In1-ghrelin and native-ghrelin was measured in plasma from an additional cohort of PCa-patients with different risk levels (n = 30) and control-healthy patients (n = 20). In vivo functional (proliferation/migration) and mechanistic (gene expression/signaling-pathways) assays were performed in PCa-cell lines in response to In1-ghrelin and native-ghrelin treatment, overexpression and/or silencing. Finally, tumor progression was monitored in nude-mice injected with PCa-cells overexpressing In1-ghrelin, native-ghrelin and empty vector (control). In1-ghrelin, but not native-ghrelin, was overexpressed in high-risk PCa-samples compared to normal-prostate (NP), and this expression correlated with that of PSA. Conversely, GHSR1a/1b expression was virtually absent. Remarkably, plasmatic In1-ghrelin, but not native-ghrelin, levels were also higher in PCa-patients compared to healthy-controls. Furthermore, In1-ghrelin treatment/overexpression, and to a much lesser extent native-ghrelin, increased aggressiveness features (cell-proliferation, migration and PSA secretion) of NP and PCa

  9. Rikkunshito, a Japanese Kampo Medicine, Ameliorates Decreased Feeding Behavior via Ghrelin and Serotonin 2B Receptor Signaling in a Novelty Stress Murine Model

    Directory of Open Access Journals (Sweden)

    Chihiro Yamada

    2013-01-01

    Full Text Available We investigated the effects of rikkunshito (RKT, a ghrelin signal enhancer, on the decrease in food intake after exposure to novelty stress in mice. RKT administration (500 mg/kg, per os improved the decrease in 6 h cumulative food intake. In control mice, the plasma acylated ghrelin levels significantly increased by 24 h fasting. In contrast, the acylated ghrelin levels did not increase by fasting in mice exposed to the novelty stress. RKT administration to the novelty stress mice showed a significant increase in the acylated ghrelin levels compared with that in the distilled-water-treated control mice. Food intake after administering serotonin 2B (5-HT2B receptor antagonists was evaluated to clarify the role of 5-HT2B receptor activation in the decrease in feeding behavior after novelty stress. SB215505 and SB204741, 5-HT2B receptor antagonists, significantly improved the decrease in food intake after exposure to novelty stress. A component of RKT, isoliquiritigenin, prevented the decrease in 6 h cumulative food intake. Isoliquiritigenin showed 5-HT2B receptor antagonistic activity in vitro. In conclusion, the results suggested that RKT improves the decrease in food intake after novelty stress probably via 5-HT2B receptor antagonism of isoliquiritigenin contained in RKT.

  10. Ghrelin receptor agonist (TZP-101) accelerates gastric emptying in adults with diabetes and symptomatic gastroparesis

    DEFF Research Database (Denmark)

    Ejskjaer, N; Vestergaard, E T; Hellström, P M

    2009-01-01

    BACKGROUND: TZP-101 is a synthetic, selective ghrelin agonist in development for gastroparesis. AIM: To assess safety and effects of TZP-101 in diabetes patients with symptomatic gastroparesis. METHODS: Adults with type 1 or type 2 diabetes mellitus received placebo and TZP-101 (80, 160, 320 or 600...... between TZP-101 and placebo. CONCLUSIONS: This proof-of-concept study demonstrates that the ghrelin agonist TZP-101 is well-tolerated in diabetes patients with moderate-to-severe chronic gastroparesis and shows statistically significant improvements in gastric emptying....

  11. Exploring the Behavioral and Metabolic Phenotype Generated by Re-Introduction of the Ghrelin Receptor in the Ventral Tegmental Area

    DEFF Research Database (Denmark)

    Skov, Louise J; Jensen, Morten; Christiansen, Søren H

    2017-01-01

    Ghrelin receptor (Ghr-R) signaling in neurons of the ventral tegmental area (VTA) can modulate dopaminergic function and the reward-related effects of both palatable foods and drugs of abuse. In this study, we re-introduced the Ghr-R in VTA neurons in Ghr-R knockout mice (Ghr-R(VTA) mice) to spec...... for the reward-related effects of activation of VTA neurons. Overall, our data suggest that re-introduction of the Ghr-R in the mesolimbic reward system of Ghr-R knockout mice increases the level of activation induced by both cocaine and novelty stress.......Ghrelin receptor (Ghr-R) signaling in neurons of the ventral tegmental area (VTA) can modulate dopaminergic function and the reward-related effects of both palatable foods and drugs of abuse. In this study, we re-introduced the Ghr-R in VTA neurons in Ghr-R knockout mice (Ghr-R(VTA) mice...

  12. Association between ghrelin gene variations, body mass index, and waist-to-hip ratio in patients with polycystic ovary syndrome.

    Science.gov (United States)

    Xu, L; Shi, Y; Gu, J; Wang, Y; Wang, L; You, L; Qi, X; Ye, Y; Chen, Z

    2014-03-01

    To investigate the association between 2 single nucleotide polymorphisms (SNP501A/C and 604 G/A) in the promoter of the ghrelin gene and the hormonal and metabolic phenotypes of polycystic ovary syndrome (PCOS) in a Chinese population. 285 patients with PCOS and 260 healthy controls were selected for a prospective, case-control study at Shandong Provincial Hospital, Jinan, China. All subjects underwent genotype analysis of the 2 single nucleotide polymorphisms of the ghrelin gene. Measurements were also taken of blood lipids, glucose, and hormone levels, and calculations of body mass index (BMI) and waist-to-hip ratio (WHR) were performed to detect hormonal and metabolic phenotypes. No significant diff erences in polymorphism genotypes were found between PCOS patients and healthy controls. However, the frequency of the -501 A/C A allele was significantly higher in the PCOS group than in the control group. PCOS -501 A/C A carriers had significantly higher BMI and WHR than PCOS women with the CC genotype. -604 G/A polymorphisms were not associated with clinical or biochemical characteristics of PCOS. The -501 A/C polymorphism of the ghrelin gene is associated with metabolic features of PCOS in a Chinese population. © J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York.

  13. Is there an effect of ghrelin/ghrelin analogs on cancer? A systematic review

    Science.gov (United States)

    Sever, Sakine; White, Donna L

    2016-01-01

    Ghrelin is a hormone with multiple physiologic functions, including promotion of growth hormone release, stimulation of appetite and regulation of energy homeostasis. Treatment with ghrelin/ghrelin-receptor agonists is a prospective therapy for disease-related cachexia and malnutrition. In vitro studies have shown high expression of ghrelin in cancer tissue, although its role including its impact in cancer risk and progression has not been established. We performed a systematic literature review to identify peer-reviewed human or animal in vivo original research studies of ghrelin, ghrelin-receptor agonists, or ghrelin genetic variants and the risk, presence, or growth of cancer using structured searches in PubMed database as well as secondary searches of article reference lists, additional reviews and meta-analyses. Overall, 45 (73.8%) of the 61 studies reviewed, including all 11 involving exogenous ghrelin/ghrelin-receptor agonist treatment, reported either a null (no statistically significant difference) or inverse association of ghrelin/ghrelin-receptor agonists or ghrelin genetic variants with cancer risk, presence or growth; 10 (16.7%) studies reported positive associations; and 6 (10.0%) reported both negative or null and positive associations. Differences in serum ghrelin levels in cancer cases vs controls (typically lower) were reported for some but not all cancers. The majority of in vivo studies showed a null or inverse association of ghrelin with risk and progression of most cancers, suggesting that ghrelin/ghrelin-receptor agonist treatment may have a favorable safety profile to use for cancer cachexia. Additional large-scale prospective clinical trials as well as basic bioscientific research are warranted to further evaluate the safety and benefits of ghrelin treatment in patients with cancer. PMID:27552970

  14. Melatonin Receptor Genes in Vertebrates

    Directory of Open Access Journals (Sweden)

    Hua Dong Yin

    2013-05-01

    Full Text Available Melatonin receptors are members of the G protein-coupled receptor (GPCR family. Three genes for melatonin receptors have been cloned. The MT1 (or Mel1a or MTNR1A and MT2 (or Mel1b or MTNR1B receptor subtypes are present in humans and other mammals, while an additional melatonin receptor subtype, Mel1c (or MTNR1C, has been identified in fish, amphibians and birds. Another melatonin related orphan receptor, GPR50, which does not bind melatonin, is found exclusively in mammals. The hormone melatonin is secreted primarily by the pineal gland, with highest levels occurring during the dark period of a circadian cycle. This hormone acts systemically in numerous organs. In the brain, it is involved in the regulation of various neural and endocrine processes, and it readjusts the circadian pacemaker, the suprachiasmatic nucleus. This article reviews recent studies of gene organization, expression, evolution and mutations of melatonin receptor genes of vertebrates. Gene polymorphisms reveal that numerous mutations are associated with diseases and disorders. The phylogenetic analysis of receptor genes indicates that GPR50 is an outgroup to all other melatonin receptor sequences. GPR50 may have separated from a melatonin receptor ancestor before the split between MTNR1C and the MTNR1A/B ancestor.

  15. Ghrelin influences novelty seeking behavior in rodents and men.

    Science.gov (United States)

    Hansson, Caroline; Shirazi, Rozita H; Näslund, Jakob; Vogel, Heike; Neuber, Corinna; Holm, Göran; Anckarsäter, Henrik; Dickson, Suzanne L; Eriksson, Elias; Skibicka, Karolina P

    2012-01-01

    Recent discoveries indicate an important role for ghrelin in drug and alcohol reward and an ability of ghrelin to regulate mesolimbic dopamine activity. The role of dopamine in novelty seeking, and the association between this trait and drug and alcohol abuse, led us to hypothesize that ghrelin may influence novelty seeking behavior. To test this possibility we applied several complementary rodent models of novelty seeking behavior, i.e. inescapable novelty-induced locomotor activity (NILA), novelty-induced place preference and novel object exploration, in rats subjected to acute ghrelin receptor (growth hormone secretagogue receptor; GHSR) stimulation or blockade. Furthermore we assessed the possible association between polymorphisms in the genes encoding ghrelin and GHSR and novelty seeking behavior in humans. The rodent studies indicate an important role for ghrelin in a wide range of novelty seeking behaviors. Ghrelin-injected rats exhibited a higher preference for a novel environment and increased novel object exploration. Conversely, those with GHSR blockade drastically reduced their preference for a novel environment and displayed decreased NILA. Importantly, the mesolimbic ventral tegmental area selective GHSR blockade was sufficient to reduce the NILA response indicating that the mesolimbic GHSRs might play an important role in the observed novelty responses. Moreover, in untreated animals, a striking positive correlation between NILA and sucrose reward behavior was detected. Two GHSR single nucleotide polymorphisms (SNPs), rs2948694 and rs495225, were significantly associated with the personality trait novelty seeking, as assessed using the Temperament and Character Inventory (TCI), in human subjects. This study provides the first evidence for a role of ghrelin in novelty seeking behavior in animals and humans, and also points to an association between food reward and novelty seeking in rodents.

  16. Characterization of the insulin sensitivity of ghrelin receptor KO mice using glycemic clamps

    Directory of Open Access Journals (Sweden)

    Morgan Kristen

    2011-01-01

    Full Text Available Abstract Background We and others have demonstrated previously that ghrelin receptor (GhrR knock out (KO mice fed a high fat diet (HFD have increased insulin sensitivity and metabolic flexibility relative to WT littermates. A striking feature of the HFD-fed GhrR KO mouse is the dramatic decrease in hepatic steatosis. To characterize further the underlying mechanisms of glucose homeostasis in GhrR KO mice, we conducted both hyperglycemic (HG and hyperinsulinemic-euglycemic (HI-E clamps. Additionally, we investigated tissue glucose uptake and specifically examined liver insulin sensitivity. Results Consistent with glucose tolerance-test data, in HG clamp experiments, GhrR KO mice showed a reduction in glucose-stimulated insulin release relative to WT littermates. Nevertheless, a robust 1st phase insulin secretion was still achieved, indicating that a healthy β-cell response is maintained. Additionally, GhrR KO mice demonstrated both a significantly increased glucose infusion rate and significantly reduced insulin requirement for maintenance of the HG clamp, consistent with their relative insulin sensitivity. In HI-E clamps, both LFD-fed and HFD-fed GhrR KO mice showed higher peripheral insulin sensitivity relative to WT littermates as indicated by a significant increase in insulin-stimulated glucose disposal (Rd, and decreased hepatic glucose production (HGP. HFD-fed GhrR KO mice showed a marked increase in peripheral tissue glucose uptake in a variety of tissues, including skeletal muscle, brown adipose tissue and white adipose tissue. GhrR KO mice fed a HFD also showed a modest, but significant decrease in conversion of pyruvate to glucose, as would be anticipated if these mice displayed increased liver insulin sensitivity. Additionally, the levels of UCP2 and UCP1 were reduced in the liver and BAT, respectively, in GhrR KO mice relative to WT mice. Conclusions These results indicate that improved glucose homeostasis of GhrR KO mice is

  17. Association Study between Ghrelin Gene Polymorphism and Metabolic Syndrome in a Han Chinese Population.

    Science.gov (United States)

    You, Yueyue; Yu, Yaqin; Wu, Yanhua; Rao, Wenwang; Zhang, Yangyu; Liu, Yingyu; Yang, Guang; Fu, Yingli; Shi, Jieping; Kou, Changgui

    2017-01-01

    Ghrelin, in humans, is a hormone secreted from the stomach with an orexigenic effect, which is good for digestion and absorption, as well as regulating physical growth, metabolism, and energy balance. It is also involved in the development of metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM). This study assessed the association between single nucleotide variants of the GHRL gene and the risk of metabolic syndrome in a Han Chinese population. A case-control study was performed on 3780 Han Chinese comprising 1813 MetS cases and 1967 controls. Three missense polymorphisms in GHRL (rs26802, rs10490816, and rs696217) were selected, and the association between these polymorphisms and the risk of MetS was investigated. Metabolic syndrome was defined according to the criteria of the International Diabetes Federation (IDF). Using Pearson's 2 test, we found that there were no significant differences in genotype distributions and allele frequencies between cases and controls (all p > 0.05). There were also no significant differences in haplotype distributions between MetS cases and healthy controls. Furthermore, we confirmed that rs26802 of the GHRL gene is associated with body mass index (BMI), waist circumference, systolic blood pressure (SBP), and fasting glucose; rs10490816 is associated with triglycerides (TG) and total cholesterol (TC); while rs696217 is associated with hip circumference and fasting glucose. We concluded that mutations in the GHRL gene did not confer risk for MetS in our study population. Therefore, functional analysis and replication studies in other populations are needed to further investigate the exact role of the GHRL gene in MetS.

  18. The Leu72Met polymorphism of the ghrelin gene is associated with a decreased risk for type 2 diabetes.

    Science.gov (United States)

    Berthold, Heiner K; Giannakidou, Eleni; Krone, Wilhelm; Mantzoros, Christos S; Gouni-Berthold, Ioanna

    2009-01-01

    Ghrelin is involved in several metabolic and cardiovascular processes. The Leu72Met polymorphism of its gene was associated with an increased risk of type 2 diabetes (DM2) in some, but not all studies. Its association with atherosclerosis is not known. We investigated 420 Caucasian subjects with DM2 and 430 controls without diabetes (56.6% male, age 62+/-10 years). The Leu72Leu genotype frequencies were 89.76/84.65%, the Leu72Met 9.52/15.12% and the Met72Met 0.71/0.23% (P=0.029) in the DM2 and controls groups, respectively. In subjects with Met72+ genotypes the risk of DM2 was significantly decreased (univariate OR 0.63, 95% CI 0.42-0.95, P=0.026). In a logistic regression model, body mass index, hypertension and a positive family history for diabetes were predictors of diabetes while the polymorphism remained negatively associated with the disease (OR 0.62, 95% CI 0.40-0.97, P=0.036). After adjusting for known risk factors for atherosclerosis, the Met72+ variant was not associated with atherosclerotic disease (OR 1.41, 95% CI 0.78-2.54, P=0.25). Ghrelin concentrations were not associated with the polymorphism, DM2 or atherosclerotic disease. The Leu72Met polymorphism of the ghrelin gene is associated with a decreased risk for DM2. There is no association between the variant and atherosclerotic disease or ghrelin concentrations.

  19. Ghrelin precursor gene polymorphism and methamphetamine dependence in the Korean population.

    Science.gov (United States)

    Yoon, Su-Jung; Pae, Chi-Un; Lee, Heejin; Choi, Bomoon; Kim, Tae-Suk; Lyoo, In Kyoon; Kwon, Do-Hoon; Kim, Dai-Jin

    2005-12-01

    Ghrelin is a recently isolated brain-gut peptide that has growth hormone-releasing and appetite-inducing activities. Several recent studies have suggested that ghrelin plays a major role in the pathophysiology of drug-seeking behavior and anxiety. Therefore, we assessed the effect of the ghrelin precursor polymorphism on methamphetamine dependence in the Korean population. One hundred and eighteen patients with methamphetamine dependence, according to the Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV) criteria, and the 144 healthy controls were enrolled in this study. Genotyping for the ghrelin precursor polymorphism was performed by the polymerase chain reaction-restriction fragment length polymorphism-based technique. The genotypic and allelic distributions of the ghrelin precursor polymorphism in the patients with methamphetamine dependence were not significantly different from those of the control subjects. However, the Met72 carriers were associated with the emotional problems of methamphetamine dependence. The patients with the Met72 allele were more depressed and anxious than the homozygous patients with the wild Leu72 allele. The present study suggests that the ghrelin precursor polymorphism may not confer a susceptibility to the development of methamphetamine dependence in the Korean population. However, the Leu72Met polymorphism could have a potential role in the emotional problems that are associated with this disease.

  20. Transcriptomic profiling of pancreatic alpha, beta and delta cell populations identifies delta cells as a principal target for ghrelin in mouse islets

    DEFF Research Database (Denmark)

    Adriaenssens, Alice E; Svendsen, Berit; Lam, Brian Y H

    2016-01-01

    cytometry and analysed by RNA sequencing. The role of the ghrelin receptor was validated by imaging delta cell calcium concentrations using islets with delta cell restricted expression of the calcium reporter GCaMP3, and in perfused mouse pancreases. RESULTS: A database was constructed of all genes...... expressed in alpha, beta and delta cells. The gene encoding the ghrelin receptor, Ghsr, was highlighted as being highly expressed and enriched in delta cells. Activation of the ghrelin receptor raised cytosolic calcium levels in primary pancreatic delta cells and enhanced somatostatin secretion in perfused...... pancreases, correlating with a decrease in insulin and glucagon release. The inhibition of insulin secretion by ghrelin was prevented by somatostatin receptor antagonism. CONCLUSIONS/INTERPRETATION: Our transcriptomic database of genes expressed in the principal islet cell populations will facilitate...

  1. Family and population-based studies of variation within the ghrelin receptor locus in relation to measures of obesity

    DEFF Research Database (Denmark)

    Gjesing, Anette P.; Larsen, Lesli Hingstrup; Torekov, Signe Sørensen

    2010-01-01

    -carriers (mean BMI: 28+/-5 kg/m(2)) (p>0.05) could be shown. CONCLUSIONS/SIGNIFICANCE: In a population-based study sample of 15,854 Danes no association between GHSR genotypes and measures of obesity and overweight was found. Also, analyses of GHSR haplotypes lack consistent associations with obesity related......BACKGROUND: The growth hormone secretagogue receptor (GHSR) is mediating hunger sensation when stimulated by its natural ligand ghrelin. In the present study, we tested the hypothesis that common and rare variation in the GHSR locus are related to increased prevalence of obesity and overweight...... among Whites. METHODOLOGY/PRINCIPAL FINDINGS: In a population-based study sample of 15,854 unrelated, middle-aged Danes, seven variants were genotyped to capture common variation in an 11 kbp region including GHSR. These were investigated for their individual and haplotypic association with obesity...

  2. The role of GABAergic system on the inhibitory effect of ghrelin on food intake in neonatal chicks.

    Science.gov (United States)

    Jonaidi, H; Abbassi, L; Yaghoobi, M M; Kaiya, H; Denbow, D M; Kamali, Y; Shojaei, B

    2012-06-27

    Ghrelin is a gut-brain peptide that has a stimulatory effect on food intake in mammals. In contrast, this peptide decreases food intake in neonatal chicks when injected intracerebroventricularly (ICV). In mammals, neuropeptide Y (NPY) mediates the orexigenic effect of ghrelin whereas in chicks it appears that corticotrophin releasing factor (CRF) is partially involved in the inhibitory effect of ghrelin on food intake. Gamma aminobutyric acid (GABA) has a stimulatory effect on food intake in mammals and birds. In this study we investigated whether the anorectic effect of ghrelin is mediated by the GABAergic system. In Experiment 1, 3h-fasted chicks were given an ICV injection of chicken ghrelin and picrotoxin, a GABA(A) receptors antagonist. Picrotoxin decreased food intake compared to the control chicks indicating a stimulatory effect of GABA(A) receptors on food intake. However, picrotoxin did not alter the inhibitory effect of ghrelin on food intake. In Experiment 2, THIP hydrochloride, a GABA(A) receptor agonist, was used in place of picrotoxin. THIP hydrochloride appeared to partially attenuate the decrease in food intake induced by ghrelin at 30 min postinjection. In Experiment 3, the effect of ICV injection of chicken ghrelin on gene expression of glutamate decarboxylase (GAD)(1) and GAD(2), GABA synthesis enzymes in the brain stem including hypothalamus, was investigated. The ICV injection of chicken ghrelin significantly reduced GAD(2) gene expression. These findings suggest that ghrelin may decrease food intake in neonatal chicks by reducing GABA synthesis and thereby GABA release within brain feeding centers. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  3. Nonpeptide and peptide growth hormone secretagogues act both as ghrelin receptor agonist and as positive or negative allosteric modulators of ghrelin signaling

    DEFF Research Database (Denmark)

    Holst, Birgitte; Brandt, Erik; Bach, Anders

    2005-01-01

    Two nonpeptide (L692,429 and MK-677) and two peptide [GH-releasing peptide (GHRP)-6 and ghrelin] agonists were compared in binding and in signal transduction assays: calcium mobilization, inositol phosphate turnover, cAMP-responsive element (CRE), and serum-responsive element (SRE) controlled tra...

  4. GHRELIN ACTIVATES HYPOPHYSIOTROPIC CORTICOTROPIN-RELEASING FACTOR NEURONS INDEPENDENTLY OF THE ARCUATE NUCLEUS

    Science.gov (United States)

    Cabral, Agustina; Portiansky, Enrique; Sánchez-Jaramillo, Edith; Zigman, Jeffrey M.; Perello, Mario

    2016-01-01

    Previous work has established that the hormone ghrelin engages the hypothalamic-pituitary-adrenal neuroendocrine axis via activation of corticotropin-releasing factor (CRF) neurons of the hypothalamic paraventricular nucleus (PVN). The neuronal circuitry that mediates this effect of ghrelin is currently unknown. Here, we show that ghrelin-induced activation of PVN CRF neurons involved inhibition of γ-aminobutyric acid (GABA) inputs, likely via ghrelin binding sites that were localized at GABAergic terminals within the PVN. While ghrelin activated PVN CRF neurons in the presence of neuropeptide Y (NPY) receptor antagonists or in arcuate nucleus (ARC)-ablated mice, it failed to do it so in mice with ghrelin receptor expression limited to ARC agouti gene related protein (AgRP)/NPY neurons. These data support the notion that ghrelin activates PVN CRF neurons via inhibition of local GABAergic tone, in an ARC-independent manner. Furthermore, these data suggest that the neuronal circuits mediating ghrelin’s orexigenic action vs. its role as a stress signal are anatomically dissociated. PMID:26874559

  5. A ghrelin gene variant may predict crossover rate from restricting-type anorexia nervosa to other phenotypes of eating disorders: a retrospective survival analysis.

    Science.gov (United States)

    Ando, Tetsuya; Komaki, Gen; Nishimura, Hiroki; Naruo, Tetsuro; Okabe, Kenjiro; Kawai, Keisuke; Takii, Masato; Oka, Takakazu; Kodama, Naoki; Nakamoto, Chiemi; Ishikawa, Toshio; Suzuki-Hotta, Mari; Minatozaki, Kazunori; Yamaguchi, Chikara; Nishizono-Maher, Aya; Kono, Masaki; Kajiwara, Sohei; Suematsu, Hiroyuki; Tomita, Yuichiro; Ebana, Shoichi; Okamoto, Yuri; Nagata, Katsutaro; Nakai, Yoshikatsu; Koide, Masanori; Kobayashi, Nobuyuki; Kurokawa, Nobuo; Nagata, Toshihiko; Kiriike, Nobuo; Takenaka, Yoshito; Nagamine, Kiyohide; Ookuma, Kazuyoshi; Murata, Shiho

    2010-08-01

    Patients with anorexia nervosa restricting type (AN-R) often develop bulimic symptoms and crossover to AN-binge eating/purging type (AN-BP), or to bulimia nervosa (BN). We have reported earlier that genetic variants of an orexigenic peptide ghrelin are associated with BN. Here, the relationship between a ghrelin gene variant and the rate of change from AN-R to other phenotypes of eating disorders (EDs) was investigated. Participants were 165 patients with ED, initially diagnosed as AN-R. The dates of their AN-R onset and changes in diagnosis to other subtypes of ED were investigated retrospectively. Ghrelin gene 3056 T-->C SNP (single nucleotide polymorphism) was genotyped. Probability and hazard ratios were analyzed using life table analysis and Cox's proportional hazard regression model, in which the starting point was the time of AN-R onset and the outcome events were the time of (i) onset of binge eating, that is, when patients changed to binge eating AN and BN and (ii) recovery of normal weight, that is, when patients changed to BN or remission. Patients with the TT genotype at 3056 T-->C had a higher probability and hazard ratio for recovery of normal weight. The ghrelin SNP was not related with the onset of binge eating. The 3056 T-->C SNP of the ghrelin gene is related to the probability and the rate of recovery of normal body weight from restricting-type AN.

  6. Ghrelin gene: identification of missense variants and a frameshift mutation in extremely obese children and adolescents and healthy normal weight students.

    Science.gov (United States)

    Hinney, Anke; Hoch, Anne; Geller, Frank; Schäfer, Helmut; Siegfried, Wolfgang; Goldschmidt, Hanspeter; Remschmidt, Helmut; Hebebrand, Johannes

    2002-06-01

    Ghrelin induces obesity via central and peripheral mechanisms. Administration of ghrelin leads to increased food intake and decreased fat utilisation in rodents. Ghrelin levels are decreased in obese individuals. Recently, a polymorphism (Arg-51-Gln) within the ghrelin gene (GHRL) was described to be associated with obesity. We screened the GHRL coding region in 215 extremely obese German Children and adolescents (study group 1) and 93 normal weight students (study group 2) by single strand conformation polymorphism analysis (SSCP). We found the two previously described single nucleotide polymorphisms (SNP: Arg-51-Gln and Leu-72-Met) in similar frequencies in study groups 1 and 2 (allele frequencies were: 0.019 and 0.016 for the 51-Gln allele and 0.091 and 0.086 for the 72-Met allele, respectively). Hence, we could not confirm the previous finding. Additionally, two novel variants were identified within the coding region: (1) We detected one healthy normal weight individual with a frameshift mutation (2bp deletion at codon 34). This frameshift mutation affects the coding region of the mature ghrelin. Hence, it is highly likely that the normal weight student is haplo-insufficient for ghrelin. (2) An A to T transversion leads to an amino acid exchange from Gln to Leu at amino acid position 90. The frequency of the 90-Leu allele was significantly higher in the extremely obese children and adolescents (0.063) than in the normal weight students (0.016; nominal p = 0.011). Additionally, we genotyped 134 underweight students and 44 normal weight adults for this SNP. Genotype frequencies were similar in extremely obese children and adolescents, underweight students and normal weight adults (p > 0.8). In conclusion, we identified four sequence variants in the coding region of the ghrelin gene in individuals belonging to different weight extremes. A frameshift mutation was detected in a normal weight individual. None of the variants seem to influence weight regulation.

  7. Association of -604G/A and -501A/C Ghrelin and Obestatin Prepropeptide Gene Polymorphisms with Polycystic Ovary Syndrome.

    Science.gov (United States)

    Ghaleh, Talaat Dabbaghi; Skandari, Somayeh Saadat; Najafipour, Reza; Rashvand, Zahra; Darabi, Masoud; Sahmani, Mehdi

    2018-04-01

    Ghrelin hormone has an important role in a wide range of metabolic and non-metabolic processes. Polymorphisms of ghrelin gene could be associated with a large number of diseases. The aim of this study was to evaluate the association of -604G/A and -501A/C polymorphisms in ghrelin and obestatin prepropeptide gene (GHRL) with polycystic ovary syndrome (PCOS) in a sample of Iranian women. One hundred and fifty-two women with PCOS and 162 age-matched apparently healthy women as control group were enrolled in this study. The study subjects were genotyped for polymorphisms in the ghrelin gene using polymerase chain reaction-restriction fragment length polymorphism-based methods. Biochemical parameters, serum prolactin, luteinizing hormone, follicle stimulating hormone, estradiol, and testosterone were estimated by chemiluminescence assay. Serum lipids and lipoproteins were determined by standard enzymatic methods. The association between the risk of PCOS and ghrelin gene polymorphisms was examined using Multivariate analysis. The frequency of the -604G/A and -501A/C polymorphisms was not statistically different between patients and the control group of women (p = 0.12 and p = 0.21, respectively). A significantly higher level of LDL-C was found in the wild-type AA genotype compared with CC genotype of -501A/C polymorphism (p = 0.02). Our findings indicate that neither -604G/A and nor -501A/C polymorphisms of ghrelin gene are associated with PCOS, but suggest a relation between the presence of polymorphic allele of -501A/C polymorphism and LDL-C level in a sample of Iranian women.

  8. Ghrelin and cancer progression.

    Science.gov (United States)

    Lin, Tsung-Chieh; Hsiao, Michael

    2017-08-01

    Ghrelin is a small peptide with 28 amino acids, and has been characterized as the ligand of the growth hormone secretagogue receptor (GHSR). In addition to its original function in stimulating pituitary growth hormone release, ghrelin is multifunctional and plays a role in the regulation of energy balance, gastric acid release, appetite, insulin secretion, gastric motility and the turnover of gastric and intestinal mucosa. The discovery of ghrelin and GHSR expression beyond normal tissues suggests its role other than physiological function. Emerging evidences have revealed ghrelin's function in regulating several processes related to cancer progression, especially in metastasis and proliferation. We further show the relative GHRL and GHSR expression in pan-cancers from The Cancer Genome Atlas (TCGA), suggesting the potential pathological role of the axis in cancers. This review focuses on ghrelin's biological function in cancer progression, and reveals its clinical significance especially the impact on cancer patient outcome. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  9. Polymorphisms in the ghrelin gene are associated with serum high-density lipoprotein cholesterol level and not with type 2 diabetes mellitus in Koreans.

    Science.gov (United States)

    Choi, Hyung Jin; Cho, Young Min; Moon, Min Kyong; Choi, Hye Hun; Shin, Hyoung Doo; Jang, Hak Chul; Kim, Seong Yeon; Lee, Hong Kyu; Park, Kyong Soo

    2006-11-01

    Ghrelin is known to play a role in glucose metabolism and in beta-cell function. There are controversies regarding the role of ghrelin polymorphisms in diabetes and diabetes-related phenotypes. The objective of this study was to examine polymorphisms of the ghrelin gene in a Korean cohort and investigate associations between them and susceptibility to type 2 diabetes and its related phenotypes. The ghrelin gene was sequenced to identify polymorphisms in 24 DNA samples. Common variants were then genotyped in 760 type 2 diabetic patients and 641 nondiabetic subjects. Genetic associations with diabetes-related phenotypes were also analyzed. Nine polymorphisms were identified, and four common polymorphisms [g.-1500C>G, g.-1062G > C, g.-994C > T, g.+408C > A (Leu72Met)] were genotyped in a larger study. The genotype distributions of these four common polymorphisms in type 2 diabetes patients were similar to those of normal nondiabetic controls. However, these four common polymorphisms were variably associated with several diabetes-related phenotypes, such as high-density lipoprotein (HDL) cholesterol, fasting plasma glucose, and homeostasis model assessment of insulin resistance. In particular, subjects harboring g.-1062C were associated with a lower serum HDL cholesterol level after adjusting for other variables (P = 0.0004 or 0.01 after Bonferroni correction for 24 tests). The aforementioned four common polymorphisms in the ghrelin gene were not found to be significantly associated with susceptibility to type 2 diabetes mellitus in the Korean population. However, the common polymorphism g.-1062G > C in the promoter region of the ghrelin gene was found to be significantly associated with serum HDL cholesterol levels.

  10. Large-scale studies of the Leu72Met polymorphism of the ghrelin gene in relation to the metabolic syndrome and associated quantitative traits

    DEFF Research Database (Denmark)

    Bing, C; Ambye, L; Fenger, M

    2005-01-01

    Recently, low-frequency polymorphisms in the coding region of the ghrelin gene were suggested to be involved in the aetiology of obesity and to modulate glucose-induced insulin secretion in different ethnic study groups. The objective of the present large study was to investigate whether the Leu7...

  11. Association of Ghrelin Gene Polymorphisms and Serum Ghrelin Levels with the Risk of Hepatitis B Virus-Related Liver Diseases in a Chinese Population.

    Directory of Open Access Journals (Sweden)

    Xiaolian Zhang

    Full Text Available The functions of ghrelin (GHRL include anti-inflammatory effects, reduction of the fibrogenic response, protection of liver tissue, and regulation of cell proliferation. Genetic variations in the GHRL gene may play an important role in the development of chronic hepatitis B (CHB, liver cirrhosis (LC and hepatocellular carcinoma (HCC. Therefore, we investigated whether GHRL gene polymorphisms and its serum levels are associated with hepatitis B virus (HBV-related diseases risk in a Chinese population.176 patients with CHB, 106 patients with HBV-related LC, 151 patients with HBV-related HCC, and 167 healthy controls were recruited in the study. Genotyping of GHRL rs26311, rs27647, rs696217, and rs34911341 polymorphisms were determined with the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP and DNA sequencing. The serum GHRL concentrations were determined using enzyme-linked immunosorbent assay (ELISA.Binary logistic regression analyses adjusting for gender and age revealed that a significant increased risk of LC was found in the GHRL rs26311 GC genotype and combined GC+CC genotypes when compared with the GG genotype (GC vs. GG: OR = 1.671, 95% CI = 1.013-2.757, P = 0.044; GC+CC vs. GG: OR = 1.674, 95% CI = 1.040-2.696, P = 0.034. In subgroup analysis by gender, binary logistic regression analyses adjusting for age showed that the GHRL rs26311 C allele and combined GC+CC genotypes were associated with a significantly increased risk to LC in males (C vs. G OR = 1.416, 95% CI = 1.017-1.972, P = 0.040; GC+CC vs. GG: OR = 1.729, 95% CI = 1.019-2.933, P = 0.042. In addition, we found significant decreased serum GHRL levels in LC patients compared with the healthy controls. However, there was no significant association of the GHRL rs26311 polymorphism with serum GHRL levels in LC patients.These observations suggest that the GHRL rs26311 polymorphism is associated with an increased risk to HBV-related LC, especially in men

  12. Association of Ghrelin Gene Polymorphisms and Serum Ghrelin Levels with the Risk of Hepatitis B Virus-Related Liver Diseases in a Chinese Population.

    Science.gov (United States)

    Zhang, Xiaolian; Zhai, Limin; Rong, Chengzhi; Qin, Xue; Li, Shan

    2015-01-01

    The functions of ghrelin (GHRL) include anti-inflammatory effects, reduction of the fibrogenic response, protection of liver tissue, and regulation of cell proliferation. Genetic variations in the GHRL gene may play an important role in the development of chronic hepatitis B (CHB), liver cirrhosis (LC) and hepatocellular carcinoma (HCC). Therefore, we investigated whether GHRL gene polymorphisms and its serum levels are associated with hepatitis B virus (HBV)-related diseases risk in a Chinese population. 176 patients with CHB, 106 patients with HBV-related LC, 151 patients with HBV-related HCC, and 167 healthy controls were recruited in the study. Genotyping of GHRL rs26311, rs27647, rs696217, and rs34911341 polymorphisms were determined with the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing. The serum GHRL concentrations were determined using enzyme-linked immunosorbent assay (ELISA). Binary logistic regression analyses adjusting for gender and age revealed that a significant increased risk of LC was found in the GHRL rs26311 GC genotype and combined GC+CC genotypes when compared with the GG genotype (GC vs. GG: OR = 1.671, 95% CI = 1.013-2.757, P = 0.044; GC+CC vs. GG: OR = 1.674, 95% CI = 1.040-2.696, P = 0.034). In subgroup analysis by gender, binary logistic regression analyses adjusting for age showed that the GHRL rs26311 C allele and combined GC+CC genotypes were associated with a significantly increased risk to LC in males (C vs. G OR = 1.416, 95% CI = 1.017-1.972, P = 0.040; GC+CC vs. GG: OR = 1.729, 95% CI = 1.019-2.933, P = 0.042). In addition, we found significant decreased serum GHRL levels in LC patients compared with the healthy controls. However, there was no significant association of the GHRL rs26311 polymorphism with serum GHRL levels in LC patients. These observations suggest that the GHRL rs26311 polymorphism is associated with an increased risk to HBV-related LC, especially in men. We also

  13. Genetic variation of the ghrelin signaling system in females with severe alcohol dependence.

    Science.gov (United States)

    Landgren, Sara; Jerlhag, Elisabet; Hallman, Jarmila; Oreland, Lars; Lissner, Lauren; Strandhagen, Elisabeth; Thelle, Dag S; Zetterberg, Henrik; Blennow, Kaj; Engel, Jörgen A

    2010-09-01

    Central ghrelin signaling is required for the rewarding effects of alcohol in mice. Because ghrelin is implied in other addictive behaviors such as eating disorders and smoking, and because there is co-morbidity between these disorders and alcohol dependence, the ghrelin signaling system could be involved in mediating reward in general. Furthermore, in humans, single nucleotide polymorphisms (SNPs) and haplotypes of the pro-ghrelin gene (GHRL) and the ghrelin receptor gene (GHSR) have previously been associated with increased alcohol consumption and increased body weight. Known gender differences in plasma ghrelin levels prompted us to investigate genetic variation of the ghrelin signaling system in females with severe alcohol dependence (n = 113) and in a selected control sample of female low-consumers of alcohol from a large cohort study in southwest Sweden (n = 212). Six tag SNPs in the GHRL (rs696217, rs3491141, rs4684677, rs35680, rs42451, and rs26802) and four tag SNPs in the GHSR (rs495225, rs2232165, rs572169, and rs2948694) were genotyped in all individuals. We found that one GHRL haplotype was associated with reports of paternal alcohol dependence as well as with reports of withdrawal symptoms in the female alcohol-dependent group. Associations with 2 GHSR haplotypes and smoking were also shown. One of these haplotypes was also negatively associated with BMI in controls, while another haplotype was associated with having the early-onset, more heredity-driven, type 2 form of alcohol dependence in the patient group. Taken together, the genes encoding the ghrelin signaling system cannot be regarded as major susceptibility genes for female alcohol dependence, but is, however, involved in paternal heritability and may affect other reward- and energy-related factors such as smoking and BMI.

  14. On the regulation of ghrelin secretion

    International Nuclear Information System (INIS)

    Schmidt, A.

    2003-04-01

    The newly discovered endogenous ligand of the growth hormone secretagogue receptor, ghrelin, is not only a potent stimulus for growth hormone secretion, but exerts also potent orexigenic (appetite stimulatory) effects. The purpose of this thesis was to elucidate the mechanisms underlying the regulation of this peptide in three different studies. Ghrelin serum levels were analyzed with a commercially available radioimmunoassay (RIA). In 18 patients on chronic hemodialysis ghrelin levels were investigated and acetomorphine parameters were determined in order to correlate the nutritional status to the ghrelin serum levels. The potential elimination of ghrelin during dialysis was also tested. Ghrelin levels were significantly elevated compared to controls. No correlation was found between Ghrelin serum levels and anthropometric parameters. It can be speculated that chronic hemodialysis patients are not only resistant to growth hormone, but also to ghrelin. In 8 healthy volunteers a potential involvement of ghrelin in the response of growth hormone to acute exercise was tested. During three different exercise intensities (low, submaximal and maximal exercise) ghrelin levels were measured. No changes in ghrelin plasma concentrations could be detected. These findings suggest that ghrellin is not involved in the growth hormone response to acute exercise. The purpose of the third study was to enlighten the mechanisms underlying the postprandial decrease of ghrelin. During a double-blind placebo-controlled study increasing systemic glucose concentrations were attained with infusion of glucose, in order to represent fasting and postprandial conditions. Ghrelin levels were studied during coinfusion of insulin, somatostatin and placebo. It could be demonstrated that, the regulation of the postprandial decrease in ghrelin is not regulated by insulin or glucose, but by somatostatin. (author)

  15. Molecular screening of the ghrelin gene in Italian obese children: the Leu72Met variant is associated with an earlier onset of obesity.

    Science.gov (United States)

    Miraglia del Giudice, E; Santoro, N; Cirillo, G; Raimondo, P; Grandone, A; D'Aniello, A; Di Nardo, M; Perrone, L

    2004-03-01

    To test whether ghrelin variants could play a role in modulating some aspects of the obese phenotype during childhood. We screened the ghrelin gene in 300 Italian obese children and adolescents (mean age 10.5+/-3.2 y; range 4-19 y) and 200 controls by using the single-strand conformation polymorphism and the restriction fragment length polymoprhism analysis. No mutations were detected with the exception of two previously described polymorphisms, Arg51Gln and Leu72Met. For both variations, allelic frequencies were similar between patients and controls. Interestingly, we showed that the Leu72Met polymorphism was associated with differences in the age at obesity onset. Patients with the Met72 allele became obese earlier than homozygous patients for the wild Leu72 allele. The logrank test comparing the plots of the complement of Kaplan-Meier estimates between the two groups of patients was statistically significant (Pghrelin variations cause the obesity due to single-gene mutations. The Leu72Met polymorphism of the ghrelin gene seems to play a role in anticipating the onset of obesity among children suggesting, therefore, that ghrelin may be involved in the pathophysiology of human adiposity.

  16. Ghrelin and gastrointestinal stromal tumors.

    Science.gov (United States)

    Zhu, Chang-Zhen; Liu, Dong; Kang, Wei-Ming; Yu, Jian-Chun; Ma, Zhi-Qiang; Ye, Xin; Li, Kang

    2017-03-14

    Ghrelin, as a kind of multifunctional protein polypeptide, is mainly produced in the fundus of the stomach and can promote occurrence and development of many tumors, including gastrointestinal tumors, which has been proved by the relevant researches. Most gastrointestinal stromal tumors (GISTs, about 80%), as the most common mesenchymal tumor, also develop in the fundus. Scientific research has confirmed that ghrelin, its receptors and mRNA respectively can be found in GISTs, which demonstrated the existence of a ghrelin autocrine/paracrine loop in GIST tissues. However, no reports to date have specified the mechanism whether ghrelin can promote the occurrence and development of GISTs. Studies of pulmonary artery endothelial cells in a low-oxygen environment and cardiac muscle cells in an ischemic environment have shown that ghrelin can activate the phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathway. Moreover, some studies of GISTs have confirmed that activation of the PI3K/AKT/mTOR pathway can indeed promote the growth and progression of GISTs. Whether ghrelin is involved in the development or progression of GISTs through certain pathways remains unknown. Can we find a new target for the treatment of GISTs? This review explores and summaries the relationship among ghrelin, the PI3K/AKT/mTOR pathway and the development of GISTs.

  17. Acylation type determines ghrelin's effects on energy homeostasis in rodents

    DEFF Research Database (Denmark)

    Heppner, Kristy; Chaudhary, Nilika; Müller, Timo D

    2012-01-01

    Ghrelin is a gastrointestinal polypeptide that acts through the ghrelin receptor (GHSR) to promote food intake and increase adiposity. Activation of GHSR requires the presence of a fatty-acid (FA) side chain on amino acid residue serine 3 of the ghrelin molecule. However, little is known about th...

  18. No association of the neuropeptide Y (Leu7Pro) and ghrelin gene (Arg51Gln, Leu72Met, Gln90Leu) single nucleotide polymorphisms with eating disorders.

    Science.gov (United States)

    Kindler, Jochen; Bailer, Ursula; de Zwaan, Martina; Fuchs, Karoline; Leisch, Friedrich; Grün, Bettina; Strnad, Alexandra; Stojanovic, Mirjana; Windisch, Julia; Lennkh-Wolfsberg, Claudia; El-Giamal, Nadja; Sieghart, Werner; Kasper, Siegfried; Aschauer, Harald

    2011-06-01

    Genetic factors likely contribute to the biological vulnerability of eating disorders. Case-control association study on one neuropeptide Y gene (Leu7Pro) polymorphism and three ghrelin gene (Arg51Gln, Leu72Met and Gln90Leu) polymorphisms. 114 eating disorder patients (46 with anorexia nervosa, 30 with bulimia nervosa, 38 with binge eating disorder) and 164 healthy controls were genotyped. No differences were detected between patients and controls for any of the four polymorphisms in allele frequency and genotype distribution (P > 0.05). Allele frequencies and genotypes had no significant influence on body mass index (P > 0.05) in eating disorder patients. Positive findings of former case-control studies of associations between ghrelin gene polymorphisms and eating disorders could not be replicated. Neuropeptide Y gene polymorphisms have not been investigated in eating disorders before.

  19. KATP channels in the nodose ganglia mediate the orexigenic actions of ghrelin

    Science.gov (United States)

    Grabauskas, Gintautas; Wu, Xiaoyin; Lu, Yuanxu; Heldsinger, Andrea; Song, Il; Zhou, Shi-Yi; Owyang, Chung

    2015-01-01

    Abstract Ghrelin is the only known hunger signal derived from the peripheral tissues. Ghrelin overcomes the satiety signals evoked by anorexigenic molecules, such as cholecystokinin (CCK) and leptin, to stimulate feeding. The mechanisms by which ghrelin reduces the sensory signals evoked by anorexigenic hormones, which act via the vagus nerve to stimulate feeding, are unknown. Patch clamp recordings of isolated rat vagal neurons show that ghrelin hyperpolarizes neurons by activating K+ conductance. Administering a KATP channel antagonist or silencing Kir6.2, a major subunit of the KATP channel, abolished ghrelin inhibition in vitro and in vivo. Patch clamp studies show that ghrelin inhibits currents evoked by leptin and CCK-8, which operate through independent ionic channels. The inhibitory actions of ghrelin were abolished by treating the vagal ganglia neurons with pertussis toxin, as well as phosphatidylinositol 3-kinase (PI3K) or extracellular signal-regulated kinase 1 and 2 (Erk1/2) small interfering RNA. In vivo gene silencing of PI3K and Erk1/2 in the nodose ganglia prevented ghrelin inhibition of leptin- or CCK-8-evoked vagal firing. Feeding experiments showed that silencing Kir6.2 in the vagal ganglia abolished the orexigenic actions of ghrelin. These data indicate that ghrelin modulates vagal ganglia neuron excitability by activating KATP conductance via the growth hormone secretagogue receptor subtype 1a–Gαi–PI3K–Erk1/2–KATP pathway. The resulting hyperpolarization renders the neurons less responsive to signals evoked by anorexigenic hormones. This provides a mechanism to explain the actions of ghrelin with respect to overcoming anorexigenic signals that act via the vagal afferent pathways. Key points Ghrelin, a hunger signalling peptide derived from the peripheral tissues, overcomes the satiety signals evoked by anorexigenic molecules, such as cholecystokinin (CCK) and leptin, to stimulate feeding. Using in vivo and in vitro electrophysiological

  20. Distinct phosphorylation sites on the ghrelin receptor, GHSR1a, establish a code that determines the functions of ß-arrestins

    Science.gov (United States)

    Bouzo-Lorenzo, Monica; Santo-Zas, Icía; Lodeiro, Maria; Nogueiras, Rubén; Casanueva, Felipe F.; Castro, Marian; Pazos, Yolanda; Tobin, Andrew B; Butcher, Adrian J.; Camiña, Jesús P.

    2016-01-01

    The growth hormone secretagogue receptor, GHSR1a, mediates the biological activities of ghrelin, which includes the secretion of growth hormone, as well as the stimulation of appetite, food intake and maintenance of energy homeostasis. Mapping phosphorylation sites on GHSR1a and knowledge of how these sites control specific functional consequences unlocks new strategies for the development of therapeutic agents targeting individual functions. Herein, we have identified the phosphorylation of different sets of sites within GHSR1a which engender distinct functionality of ß-arrestins. More specifically, the Ser362, Ser363 and Thr366 residues at the carboxyl-terminal tail were primarily responsible for ß-arrestin 1 and 2 binding, internalization and ß-arrestin-mediated proliferation and adipogenesis. The Thr350 and Ser349 are not necessary for ß-arrestin recruitment, but are involved in the stabilization of the GHSR1a-ß-arrestin complex in a manner that determines the ultimate cellular consequences of ß-arrestin signaling. We further demonstrated that the mitogenic and adipogenic effect of ghrelin were mainly dependent on the ß-arrestin bound to the phosphorylated GHSR1a. In contrast, the ghrelin function on GH secretion was entirely mediated by G protein signaling. Our data is consistent with the hypothesis that the phosphorylation pattern on the C terminus of GHSR1a determines the signaling and physiological output. PMID:26935831

  1. Effect of ghrelin on the motor deficit caused by the ablation of nigrostriatal dopaminergic cells or the inhibition of striatal dopamine receptors.

    Science.gov (United States)

    Suda, Yukari; Kuzumaki, Naoko; Narita, Michiko; Hamada, Yusuke; Shibasaki, Masahiro; Tanaka, Kenichi; Tamura, Hideki; Kawamura, Takashi; Kondo, Takashige; Yamanaka, Akihiro; Narita, Minoru

    2018-02-19

    Ghrelin plays roles in a wide range of central functions by activating the growth hormone secretagogue receptor (GHSR). This receptor has recently been found in the substantia nigra (SN) to control dopamine (DA)-related physiological functions. The dysregulation of DA neurons in the SN pars compacta (SNc) and the consequent depletion of striatal DA are known to underlie the motor deficits observed in Parkinson's disease (PD). In the present study, we further investigated the role of the SN-ghrelin system in motor function under the stereotaxic injection of AAV-CMV-FLEX-diphtheria toxin A (DTA) into the SN of dopamine transporter (DAT)-Cre (DAT SN ::DTA) mice to expunge DA neurons of the SNc. First, we confirmed the dominant expression of GHSR1a, which is a functional GHSR, in tyrosine hydroxylase (TH)-positive DA neurons in the SNc of control mice. In DAT SN ::DTA mice, we clearly observed motor dysfunction using several behavioral tests. An immunohistochemical study revealed a dramatic loss of TH-positive DA neurons in the SNc and DAT-labeled axon terminals in the striatum, and an absence of mRNAs for TH and DAT in the SN of DAT SN ::DTA mice. The mRNA level of GHSR1a was drastically decreased in the SN of these mice. In normal mice, we also found the mRNA expression of GHSR1a within GABAergic neurons in the SN pars reticulata (SNr). Under these conditions, a single injection of ghrelin into the SN failed to improve the motor deficits caused by ablation of the nigrostriatal DA network using DAT SN ::DTA mice, whereas intra-SN injection of ghrelin suppressed the motor dysfunction caused by the administration of haloperidol, which is associated with the transient inhibition of DA transmission. These findings suggest that phasic activation of the SNc-ghrelin system could improve the dysregulation of nigrostriatal DA transmission related to the initial stage of PD, but not the motor deficits under the depletion of nigrostriatal DA. Although GHSRs are found in non

  2. Ghrelin-related peptides do not modulate vasodilator nitric oxide production or superoxide levels in mouse systemic arteries.

    Science.gov (United States)

    Ku, Jacqueline M; Sleeman, Mark W; Sobey, Christopher G; Andrews, Zane B; Miller, Alyson A

    2016-04-01

    The ghrelin gene is expressed in the stomach where it ultimately encodes up to three peptides, namely, acylated ghrelin, des-acylated ghrelin and obestatin, which all have neuroendocrine roles. Recently, the authors' reported that these peptides have important physiological roles in positively regulating vasodilator nitric oxide (NO) production in the cerebral circulation, and may normally suppress superoxide production by the pro-oxidant enzyme, Nox2-NADPH oxidase. To date, the majority of studies using exogenous peptides infer that they may have similar roles in the systemic circulation. Therefore, this study examined whether exogenous and endogenous ghrelin-related peptides modulate NO production and superoxide levels in mouse mesenteric arteries and/or thoracic aorta. Using wire myography, it was found that application of exogenous acylated ghrelin, des-acylated ghrelin or obestatin to mouse thoracic aorta or mesenteric arteries failed to elicit a vasorelaxation response, whereas all three peptides elicited vasorelaxation responses of rat thoracic aorta. Also, none of the peptides modulated mouse aortic superoxide levels as measured by L-012-enhanced chemiluminescence. Next, it was found that NO bioactivity and superoxide levels were unaffected in the thoracic aorta from ghrelin-deficient mice when compared with wild-type mice. Lastly, using novel GHSR-eGFP reporter mice in combination with double-labelled immunofluorescence, no evidence was found for the growth hormone secretagogue receptor (GHSR1a) in the throracic aorta, which is the only functional ghrelin receptor identified to date. Collectively these findings demonstrate that, in contrast to systemic vessels of other species (e.g. rat and human) and mouse cerebral vessels, ghrelin-related peptides do not modulate vasodilator NO production or superoxide levels in mouse systemic arteries. © 2016 John Wiley & Sons Australia, Ltd.

  3. Association between Ghrelin gene (GHRL polymorphisms and clinical response to atypical antipsychotic drugs in Han Chinese schizophrenia patients

    Directory of Open Access Journals (Sweden)

    Yang Yongfeng

    2012-02-01

    Full Text Available Abstract Background Ghrelin (GHRL is a pivotal peptide regulator of food intake, energy balance, and body mass. Weight gain (WG is a common side effect of the atypical antipsychotics (AAPs used to treat schizophrenia (SZ. Ghrelin polymorphisms have been associated with pathogenic variations in plasma lipid concentrations, blood pressure, plasma glucose, and body mass index (BMI. However, it is unclear whether GHRL polymorphisms are associated with WG due to AAPs. Furthermore, there is no evidence of an association between GHRL polymorphisms and SZ or the therapeutic response to AAPs. We explored these potential associations by genotyping GHRL alleles in SZ patients and controls. We also examined the relation between these SNPs and changes in metabolic indices during AAP treatment in SZ subgroups distinguished by high or low therapeutic response. Methods Four SNPs (Leu72Met, -501A/C, -604 G/A, and -1062 G > C were genotyped in 634 schizophrenia patients and 606 control subjects. Results There were no significant differences in allele frequencies, genotype distributions, or the distributions of two SNP haplotypes between SZ patients and healthy controls (P > 0.05. There was also no significant difference in symptom reduction between genotypes after 8 weeks of AAP treatment as measured by positive and negative symptom scale scores (PANSS. However, the -604 G/A polymorphism was associated with a greater BMI increase in response to AAP administration in both APP responders and non-responders as distinguished by PANSS score reduction (P P Conclusions These four GHRL gene SNPs were not associated with SZ in this Chinese Han population. The -604 G/A polymorphism was associated with significant BW and BMI increases during AAP treatment. Patients exhibiting higher WG showed greater improvements in positive and negative symptoms than patients exhibiting lower weight gain or weight loss.

  4. Association between ghrelin gene (GHRL) polymorphisms and clinical response to atypical antipsychotic drugs in Han Chinese schizophrenia patients.

    Science.gov (United States)

    Yang, Yongfeng; Li, Wenqiang; Zhao, Jingyuan; Zhang, Hongxing; Song, Xueqin; Xiao, Bo; Yang, Ge; Jiang, Chengdi; Zhang, Dai; Yue, Weihua; Lv, Luxian

    2012-02-28

    Ghrelin (GHRL) is a pivotal peptide regulator of food intake, energy balance, and body mass. Weight gain (WG) is a common side effect of the atypical antipsychotics (AAPs) used to treat schizophrenia (SZ). Ghrelin polymorphisms have been associated with pathogenic variations in plasma lipid concentrations, blood pressure, plasma glucose, and body mass index (BMI). However, it is unclear whether GHRL polymorphisms are associated with WG due to AAPs. Furthermore, there is no evidence of an association between GHRL polymorphisms and SZ or the therapeutic response to AAPs. We explored these potential associations by genotyping GHRL alleles in SZ patients and controls. We also examined the relation between these SNPs and changes in metabolic indices during AAP treatment in SZ subgroups distinguished by high or low therapeutic response. Four SNPs (Leu72Met, -501A/C, -604 G/A, and -1062 G > C) were genotyped in 634 schizophrenia patients and 606 control subjects. There were no significant differences in allele frequencies, genotype distributions, or the distributions of two SNP haplotypes between SZ patients and healthy controls (P > 0.05). There was also no significant difference in symptom reduction between genotypes after 8 weeks of AAP treatment as measured by positive and negative symptom scale scores (PANSS). However, the -604 G/A polymorphism was associated with a greater BMI increase in response to AAP administration in both APP responders and non-responders as distinguished by PANSS score reduction (P GHRL gene SNPs were not associated with SZ in this Chinese Han population. The -604 G/A polymorphism was associated with significant BW and BMI increases during AAP treatment. Patients exhibiting higher WG showed greater improvements in positive and negative symptoms than patients exhibiting lower weight gain or weight loss.

  5. Ghrelin and Obesity: Identifying Gaps and Dispelling Myths. A Reappraisal.

    Science.gov (United States)

    Makris, Marinos C; Alexandrou, Andreas; Papatsoutsos, Efstathios G; Malietzis, George; Tsilimigras, Diamantis I; Guerron, Alfredo D; Moris, Demetrios

    2017-01-01

    The etiology of obesity is complex. Environmental and genetic causes have been implicated in the development of this disease. Ghrelin is a hormone known to stimulate appetite. There are numerous possible actions through which ghrelin exerts its effect in the body: a) Overproduction of ghrelin, b) reduced ghrelin following meals, and c) increased receptor sensitivity to ghrelin action. Sleeve gastrectomy, a bariatric procedure, leads to reduction of ghrelin levels and subsequently to weight loss. However, there are many limitations to measurement of the fasting plasma level of the active form of ghrelin. The establishment of the exact correlation between ghrelin, appetite and obesity could be vital for the fight against obesity. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  6. Genetic variants of ghrelin in metabolic disorders.

    Science.gov (United States)

    Ukkola, Olavi

    2011-11-01

    An increasing understanding of the role of genes in the development of obesity may reveal genetic variants that, in combination with conventional risk factors, may help to predict an individual's risk for developing metabolic disorders. Accumulating evidence indicates that ghrelin plays a role in regulating food intake and energy homeostasis and it is a reasonable candidate gene for obesity-related co-morbidities. In cross-sectional studies low total ghrelin concentrations and some genetic polymorphisms of ghrelin have been associated with obesity-associated diseases. The present review highlights many of the important problems in association studies of genetic variants and complex diseases. It is known that population-specific differences in reported associations exist. We therefore conclude that more studies on variants of ghrelin gene are needed to perform in different populations to get deeper understanding on the relationship of ghrelin gene and its variants to obesity. Copyright © 2011 Elsevier Inc. All rights reserved.

  7. Polymorphisms in the bovine ghrelin precursor (GHRL) and Syndecan-1 (SDC1) genes that are associated with growth traits in cattle.

    Science.gov (United States)

    Sun, Jiajie; Jin, Qijiang; Zhang, Chunlei; Fang, Xingtang; Gu, Chuanwen; Lei, Chuzhao; Wang, Juqiang; Chen, Hong

    2011-06-01

    Transgenically expressed Syndecan-1 was found in the hypothalamic nuclei that control energy balance, and was associated with maturity-onset obesity, while ghrelin has been shown to play important roles in the control of food intake, gastric acid secretion, energy homeostasis, and glucose and lipid metabolism. However, the roles of genetic variations of Syndecan-1 and ghrelin on growth trait have few been reported in cattle. Herein, five Chinese cattle breeds were analyzed by PCR-SSCP and DNA sequencing methods. The bovine ghrelin gene showed eleven SNPs g.[267G>A, 271G>A, 290C>T, 326A>G, 327T>C, 420C>A, 569A>G, 945C>T, 993C>T, 4491A>G, 4644G>A] and three SNPs g.[420C>A, 569 A>G, 945C>T] were firstly detected in cattle. The bovine Syndecan-1 gene showed two SNPs. One SNP showed a transition C>G at position 21514, resulting in a synonymous mutation p.G(GGC)169G(GGG) and another showed a transversion C>T at position 22591, resulting in a synonymous mutation p.D(GAC)283D(GAT). In ghrelin gene, no significant associations were revealed between any variant sites and body weight, average daily gain, body sizes for different growth periods (6, 12, 18, and 24 months old), as well as for the milk yield at 305 days, milk protein rate and milk fat percentage. However, the polymorphism of Syndecan-1 gene was significantly associated with bovine birth weight and body length. Hence, we first suggested that Syndecan-1 gene could be regarded as molecular marker for superior birth weight and body length.

  8. Intrahippocampal injection of Cortistatin-14 impairs recognition memory consolidation in mice through activation of sst2, ghrelin and GABAA/B receptors.

    Science.gov (United States)

    Jiang, Jinhong; Peng, Yali; He, Zhen; Wei, Lijuan; Jin, Weidong; Wang, Xiaoli; Chang, Min

    2017-07-01

    Cortistatin-14 (CST-14), a neuropeptide related to somatostatin, is primarily localized within the cortex and hippocampus. In the hippocampus, CST-14 inhibits CA1 neuronal pyramidal cell firing and co-exists with GABA. However, its role in cognitive is still not clarified. The first aim of our study was to elucidate the role of CST-14 signaling in consolidation and reconsolidation of recognition memory in mice, using novel object recognition task. The results showed that central CST-14 induced in impairment of long-term and short-term recognition memory, indicating memory consolidation impairment effect. Similarly, we found that CST-14 did not impaired long-term and short-term reconsolidation recognition memory. To further investigate the underlying mechanisms of CST-14 in memory process, we used cyclosomatostatin (c-SOM, a selective sst 1-5 receptor antagonist), cyanamid154806 (a selective sst 2 receptor antagonist), ODN-8 (a high affinity and selectivity compound for sst 3 receptor), [d-Lys 3 ]GHRP-6 (a selective ghrelin receptor antagonist), picrotoxin (PTX, a GABA A receptor antagonist), and sacolfen (a GABA B receptor antagonist) to research its effects in recognition. Our results firstly indicated that the memory-impairing effects of CST-14 were significantly reversed by c-SOM, cyanamid154806, [d-Lys 3 ]GHRP-6, PTX and sacolfen, but not ODN-8, suggesting that the blockage of recognition memory consolidation induced by CST-14 involves sst 2 , ghrelin and GABA system. The present study provides a potential strategy to regulate memory processes, providing new evidence that reconsolidation is not a simple reiteration of consolidation. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Is Ghrelin Synthesized in the Central Nervous System?

    Science.gov (United States)

    Cabral, Agustina; López Soto, Eduardo J; Epelbaum, Jacques; Perelló, Mario

    2017-03-15

    Ghrelin is an octanoylated peptide that acts via its specific receptor, the growth hormone secretagogue receptor type 1a (GHSR-1a), and regulates a vast variety of physiological functions. It is well established that ghrelin is predominantly synthesized by a distinct population of endocrine cells located within the gastric oxyntic mucosa. In addition, some studies have reported that ghrelin could also be synthesized in some brain regions, such as the hypothalamus. However, evidences of neuronal production of ghrelin have been inconsistent and, as a consequence, it is still as a matter of debate if ghrelin can be centrally produced. Here, we provide a comprehensive review and discussion of the data supporting, or not, the notion that the mammalian central nervous system can synthetize ghrelin. We conclude that no irrefutable and reproducible evidence exists supporting the notion that ghrelin is synthetized, at physiologically relevant levels, in the central nervous system of adult mammals.

  10. Is Ghrelin Synthesized in the Central Nervous System?

    Directory of Open Access Journals (Sweden)

    Agustina Cabral

    2017-03-01

    Full Text Available Ghrelin is an octanoylated peptide that acts via its specific receptor, the growth hormone secretagogue receptor type 1a (GHSR-1a, and regulates a vast variety of physiological functions. It is well established that ghrelin is predominantly synthesized by a distinct population of endocrine cells located within the gastric oxyntic mucosa. In addition, some studies have reported that ghrelin could also be synthesized in some brain regions, such as the hypothalamus. However, evidences of neuronal production of ghrelin have been inconsistent and, as a consequence, it is still as a matter of debate if ghrelin can be centrally produced. Here, we provide a comprehensive review and discussion of the data supporting, or not, the notion that the mammalian central nervous system can synthetize ghrelin. We conclude that no irrefutable and reproducible evidence exists supporting the notion that ghrelin is synthetized, at physiologically relevant levels, in the central nervous system of adult mammals.

  11. Effects of ghrelin and des-acyl ghrelin on neurogenesis of the rat fetal spinal cord

    International Nuclear Information System (INIS)

    Sato, Miho; Nakahara, Keiko; Goto, Shintaro; Kaiya, Hiroyuki; Miyazato, Mikiya; Date, Yukari; Nakazato, Masamitsu; Kangawa, Kenji; Murakami, Noboru

    2006-01-01

    Expressions of the growth hormone secretagogue receptor (GHS-R) mRNA and its protein were confirmed in rat fetal spinal cord tissues by RT-PCR and immunohistochemistry. In vitro, over 3 nM ghrelin and des-acyl ghrelin induced significant proliferation of primary cultured cells from the fetal spinal cord. The proliferating cells were then double-stained using antibodies against the neuronal precursor marker, nestin, and the cell proliferation marker, 5-bromo-2'-deoxyuridine (BrdU), and the nestin-positive cells were also found to be co-stained with antibody against GHS-R. Furthermore, binding studies using [ 125 I]des-acyl ghrelin indicated the presence of a specific binding site for des-acyl ghrelin, and confirmed that the binding was displaced with unlabeled des-acyl ghrelin or ghrelin. These results indicate that ghrelin and des-acyl ghrelin induce proliferation of neuronal precursor cells that is both dependent and independent of GHS-R, suggesting that both ghrelin and des-acyl ghrelin are involved in neurogenesis of the fetal spinal cord

  12. The role of ghrelin in the organism

    Directory of Open Access Journals (Sweden)

    Beata Polińska

    2011-01-01

    Full Text Available Ghrelin was discovered in 1999 as an endogenous ligand of the growth hormone secretagogue receptor (GHS-R. About 60–70�0of ghrelin in the blood is released from oxyntic cells (X/A-like cells of the stomach body and fundus. Ghrelin acts via interactions with specific receptors located, for example, in the hypothalamus, pituitary gland, pancreas, kidneys, myocardium, blood vessels, adipose tissue, ovaries and placenta. Ghrelin is directly related to the control of energy balance through appetite stimulation, food intake increase and meal initiation as well as reduction of adipose tissue utilization. Moreover, ghrelin increases hydrochloric acid secretion and gastrin release, controls gastric motility, and also protects the mucous membrane of the stomach and intestine. Besides its effects on the gastrointestinal tract, ghrelin influences the cardiovascular system, bone metabolism, insulin secretion, gonad function and the immune system. It exerts anti-inflammatory effects and inhibits apoptosis of cardiomyocytes and endothelium. The plasma ghrelin level depends on the nutrition level and lifestyle factors. This article describes the most important functions of ghrelin in the organism.

  13. The role of the central ghrelin system in reward from food and chemical drugs.

    Science.gov (United States)

    Dickson, Suzanne L; Egecioglu, Emil; Landgren, Sara; Skibicka, Karolina P; Engel, Jörgen A; Jerlhag, Elisabet

    2011-06-20

    Here we review recent advances that identify a role for the central ghrelin signalling system in reward from both natural rewards (such as food) and artificial rewards (that include alcohol and drugs of abuse). Whereas ghrelin emerged as a stomach-derived hormone involved in energy balance, hunger and meal initiation via hypothalamic circuits, it now seems clear that it also has a role in motivated reward-driven behaviours via activation of the so-called "cholinergic-dopaminergic reward link". This reward link comprises a dopamine projection from the ventral tegmental area (VTA) to the nucleus accumbens together with a cholinergic input, arising primarily from the laterodorsal tegmental area. Ghrelin administration into the VTA or LDTg activates the "cholinergic-dopaminergic" reward link, suggesting that ghrelin may increase the incentive value of motivated behaviours such as reward-seeking behaviour ("wanting" or "incentive motivation"). Further, direct injection of ghrelin into the brain ventricles or into the VTA increases the consumption of rewarding foods as well as alcohol in mice and rats. Studies in rodents show beneficial effects of ghrelin receptor (GHS-R1A) antagonists to suppress the intake of palatable food, to reduce preference for caloric foods, to suppress food reward and motivated behaviour for food. They have also been shown to reduce alcohol consumption, suppress reward induced by alcohol, cocaine and amphetamine. Furthermore, variations in the GHS-R1A and pro-ghrelin genes have been associated with high alcohol consumption, smoking and increased weight gain in alcohol dependent individuals as well as with bulimia nervosa and obesity. Thus, the central ghrelin signalling system interfaces neurobiological circuits involved in reward from food as well as chemical drugs; agents that directly or indirectly suppress this system emerge as potential candidate drugs for suppressing problematic over-eating that leads to obesity as well as for the

  14. Metabolic and cardiovascular effects of ghrelin

    Directory of Open Access Journals (Sweden)

    2012-03-01

    Full Text Available Ghrelin is an endogenous ligand for growth hormone receptor, which is synthesized as a prohormone, and then proteolytically converted into 28-amino acid peptide. This peptide stimulates the secretion of growth hormone, regulates food intake, effect on carbohydrate and lipid metabolism. Ghrelin enhances the bioavailability of nitric oxide and maintains the balance between endothelin-1 and nitric oxide in the vascular wall. It increases cardiac output, and reduces blood pressure and systemic vascular resistance. Antiinflammatory effect of ghrelin is also appreciated. Since ghrelin is a circulating peptide that stimulates appetite and regulate energy balance, and its role in the development of obesity and type 2 diabetes it is the subject of intense research. A variety of metabolic functions of ghrelin requires extreme caution in the use of therapeutic approaches aimed at the stimulation or blockade of its action.

  15. The Leu72Met Polymorphism of the Prepro-ghrelin Gene is Associated With Alcohol Consumption and Subjective Responses to Alcohol: Preliminary Findings.

    Science.gov (United States)

    Suchankova, Petra; Yan, Jia; Schwandt, Melanie L; Stangl, Bethany L; Jerlhag, Elisabet; Engel, Jörgen A; Hodgkinson, Colin A; Ramchandani, Vijay A; Leggio, Lorenzo

    2017-07-01

    The orexigenic peptide ghrelin may enhance the incentive value of food-, drug- and alcohol-related rewards. Consistent with preclinical findings, human studies indicate a role of ghrelin in alcohol use disorders (AUD). In the present study an a priori hypothesis-driven analysis was conducted to investigate whether a Leu72Met missense polymorphism (rs696217) in the prepro-ghrelin gene (GHRL), is associated with AUD, alcohol consumption and subjective responses to alcohol. Association analysis was performed using the National Institute on Alcohol Abuse and Alcoholism (NIAAA) clinical sample, comprising AUD individuals and controls (N = 1127). Then, a post-hoc analysis using data from a human laboratory study of intravenous alcohol self-administration (IV-ASA, N = 144) was performed to investigate the association of this SNP with subjective responses following a fixed dose of alcohol (priming phase) and alcohol self-administration (ad libitum phase). The case-control study revealed a trend association (N = 1127, OR = 0.665, CI = 0.44-1.01, P = 0.056) between AUD diagnosis and Leu72Met. In AUD subjects, the SNP was associated with significantly lower average drinks per day (n = 567, β = -2.49, 95% CI = -4.34 to -0.64, P = 0.008) and significantly fewer heavy drinking days (n = 567, β = -12.00, 95% CI = -19.10 to -4.89, P polymorphism in the prepro-ghrelin gene, is associated with alcohol use disorder, alcohol consumption and subjective responses to alcohol. Although preliminary, results suggest that the Leu72Leu genotype may lead to increased risk of alcohol use disorder possibly via mechanisms involving a lower response to alcohol. Medical Council on Alcohol and Oxford University Press 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  16. Association between Ghrelin gene (GHRL) polymorphisms and clinical response to atypical antipsychotic drugs in Han Chinese schizophrenia patients

    OpenAIRE

    Yang Yongfeng; Li Wenqiang; Zhao Jingyuan; Zhang Hongxing; Song Xueqin; Xiao Bo; Yang Ge; Jiang Chengdi; Zhang Dai; Yue Weihua; Lv Luxian

    2012-01-01

    Abstract Background Ghrelin (GHRL) is a pivotal peptide regulator of food intake, energy balance, and body mass. Weight gain (WG) is a common side effect of the atypical antipsychotics (AAPs) used to treat schizophrenia (SZ). Ghrelin polymorphisms have been associated with pathogenic variations in plasma lipid concentrations, blood pressure, plasma glucose, and body mass index (BMI). However, it is unclear whether GHRL polymorphisms are associated with WG due to AAPs. Furthermore, there is no...

  17. Ghrelin-induced hippocampal neurogenesis and enhancement of cognitive function are mediated independently of GH/IGF-1 axis: lessons from the spontaneous dwarf rats.

    Science.gov (United States)

    Li, Endan; Kim, Yumi; Kim, Sehee; Park, Seungjoon

    2013-01-01

    We recently have reported that ghrelin modulates adult hippocampal neurogenesis. However, there is a possibility that the action of ghrelin on hippocampal neurogenesis could be, in part, due to the ability of ghrelin to stimulate the GH/insulin-like growth factor (IGF)-1 axis, where both GH and IGF-1 infusions are known to increase hippocampal neurogenesis. To explore this possibility, we assessed the impact of ghrelin on progenitor cell proliferation and differentiation in the dentate gyrus (DG) of spontaneous dwarf rats (SDRs), a dwarf strain with a mutation of the GH gene resulting in total loss of GH. Double immunohistochemical staining revealed that Ki-67-positive progenitor cells and doublecortin (DCX)-positive neuroblasts in the DG of the SDRs expressed ghrelin receptors. We found that ghrelin treatment in the SDRs significantly increased the number of proliferating cell nuclear antigen- and BrdU-labeled cells in the DG. The number of DCX-labeled cells in the DG of ghrelin-treated SDRs was also significantly increased compared with the vehicle-treated controls. To test whether ghrelin has a direct effect on cognitive performance independently of somatotropic axis, hippocampus-dependent learning and memory were assessed using the Y-maze and novel object recognition (NOR) test in the SDRs. Ghrelin treatment for 4 weeks by subcutaneous osmotic pump significantly increased alternation rates in the Y-maze and exploration time for novel object in the NOR test compared to vehicle-treated controls. Our results indicate that ghrelin-induced adult hippocampal neurogenesis and enhancement of cognitive function are mediated independently of somatotropic axis.

  18. Central Ghrelin Resistance Permits the Overconsolidation of Fear Memory.

    Science.gov (United States)

    Harmatz, Elia S; Stone, Lauren; Lim, Seh Hong; Lee, Graham; McGrath, Anna; Gisabella, Barbara; Peng, Xiaoyu; Kosoy, Eliza; Yao, Junmei; Liu, Elizabeth; Machado, Nuno J; Weiner, Veronica S; Slocum, Warren; Cunha, Rodrigo A; Goosens, Ki A

    2017-06-15

    There are many contradictory findings about the role of the hormone ghrelin in aversive processing, with studies suggesting that ghrelin signaling can both inhibit and enhance aversion. Here, we characterize and reconcile the paradoxical role of ghrelin in the acquisition of fearful memories. We used enzyme-linked immunosorbent assay to measure endogenous acyl-ghrelin and corticosterone at time points surrounding auditory fear learning. We used pharmacological (systemic and intra-amygdala) manipulations of ghrelin signaling and examined several aversive and appetitive behaviors. We also used biotin-labeled ghrelin to visualize ghrelin binding sites in coronal brain sections of amygdala. All work was performed in rats. In unstressed rodents, endogenous peripheral acyl-ghrelin robustly inhibits fear memory consolidation through actions in the amygdala and accounts for virtually all interindividual variability in long-term fear memory strength. Higher levels of endogenous ghrelin after fear learning were associated with weaker long-term fear memories, and pharmacological agonism of the ghrelin receptor during the memory consolidation period reduced fear memory strength. These fear-inhibitory effects cannot be explained by changes in appetitive behavior. In contrast, we show that chronic stress, which increases both circulating endogenous acyl-ghrelin and fear memory formation, promotes profound loss of ghrelin binding sites in the amygdala and behavioral insensitivity to ghrelin receptor agonism. These studies provide a new link between stress, a novel type of metabolic resistance, and vulnerability to excessive fear memory formation and reveal that ghrelin can regulate negative emotionality in unstressed animals without altering appetite. Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  19. Genetic manipulation of the ghrelin signaling system in male mice reveals bone compartment specificity of acylated and unacylated ghrelin in the regulation of bone remodeling

    Science.gov (United States)

    Ghrelin receptor-deficient (Ghsr-/-) mice that lack acylated ghrelin (AG) signaling retain a metabolic response to unacylated ghrelin (UAG). Recently, we showed that Ghsr-deficiency affects bone metabolism. The aim of this study was to further establish the impact of AG and UAG on bone metabolism. W...

  20. Reduced ghrelin secretion in the hypothalamus of rats due to cisplatin-induced anorexia.

    Science.gov (United States)

    Yakabi, Koji; Sadakane, Chiharu; Noguchi, Masamichi; Ohno, Shino; Ro, Shoki; Chinen, Katsuya; Aoyama, Toru; Sakurada, Tomoya; Takabayashi, Hideaki; Hattori, Tomohisa

    2010-08-01

    Although chemotherapy with cisplatin is a widely used and effective cancer treatment, the undesirable gastrointestinal side effects associated with it, such as nausea, vomiting, and anorexia, markedly decrease patients' quality of life. To elucidate the mechanism underlying chemotherapy-induced anorexia, focusing on the hypothalamic ghrelin secretion-anorexia association, we measured hypothalamic ghrelin secretion in fasted and cisplatin-treated rats. Hypothalamic ghrelin secretion changes after vagotomy or administration of cisplatin. Cisplatin + rikkunshito, a serotonin 2C receptor antagonist or serotonin 3 receptor antagonist, was investigated. The effects of intracerebroventricular (icv) administration of ghrelin or the serotonin 2C receptor antagonist SB242084 on food intake were also evaluated in cisplatin-treated rats. Hypothalamic ghrelin secretion significantly increased in 24-h-fasted rats compared to freely fed rats and was markedly reduced 24 and 48 h after cisplatin treatment in cisplatin-treated rats compared to saline-treated rats, although their plasma ghrelin levels were comparable. In cisplatin-treated rats, icv ghrelin administration reversed the decrease in food intake, vagotomy partially restored hypothalamic ghrelin secretion, and hypothalamic serotonin 2C receptor mRNA expression increased significantly. Administration of rikkunshito (an endogenous ghrelin enhancer) or a serotonin 2C receptor antagonist reversed the decrease in hypothalamic ghrelin secretion and food intake 24 h after cisplatin treatment. Cisplatin-induced anorexia is mediated through reduced hypothalamic ghrelin secretion. Cerebral serotonin 2C receptor activation partially induces decrease in hypothalamic ghrelin secretion, and rikkunshito suppresses cisplatin-induced anorexia by enhancing this secretion.

  1. Ghrelin gene polymorphism as a genetic biomarker for prediction of therapy induced clearance in Egyptian chronic HCV patients.

    Science.gov (United States)

    Hamdy, Marwa; Kassim, Samar Kamal; Khairy, Eman; Maher, Mohsen; Mansour, Khaled Amr; Albreedy, Ashraf M

    2018-04-05

    Ghrelin (GHRL) has important implications for liver disease. It has anti-inflammatory effects, regulates cell proliferation, modulates the fibrogenic response and protects liver tissue. Genetic variations in the GHRL gene may play a crucial role in the development of chronic hepatitis (CH), liver cirrhosis (LC) and hepatocellular carcinoma (HCC). Therefore, we examined the association of GHRL gene polymorphisms (rs26312 and rs27647), and its serum level to virologic responses to combined sofosbuvir and Simeprevir therapy for a course of 12 successive weeks in Egyptian chronic hepatitis C (CHC) patients. Human genomic and clinical data were collected from 100 Egyptian participants in this study, 90 HCV patients who received sofosbuvir and Simeprevir and 10 non-HCV healthy subjects. Genotyping of GHRL rs26312 and rs27647, were determined with the TaqMan qRT-PCR allele detection assay. The serum GHRL concentrations were determined using enzyme-linked immunosorbent assay (ELISA). GHRL polymorphisms (rs26312 and rs27647) genotype distributions and allele frequencies did not differ between HCV patients and normal healthy subjects or between patient groups when compared according to the therapeutic response. In addition, we found significant lower serum GHRL levels in CHC patients compared with the healthy controls. However, there was no significant association of the GHRL rs26312 and rs27647 polymorphisms with GHRL levels in CHC patients. We conclude that GHRL SNPs (rs26312 and rs27647) do not affect response to combined sofosbuvir and Simeprevir treatment in chronic Egyptian HCV patients. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Involvement of Astrocytes in Mediating the Central Effects of Ghrelin

    Science.gov (United States)

    Frago, Laura M.; Chowen, Julie A.

    2017-01-01

    Although astrocytes are the most abundant cells in the mammalian brain, much remains to be learned about their molecular and functional features. Astrocytes express receptors for numerous hormones and metabolic factors, including the appetite-promoting hormone ghrelin. The metabolic effects of ghrelin are largely opposite to those of leptin, as it stimulates food intake and decreases energy expenditure. Ghrelin is also involved in glucose-sensing and glucose homeostasis. The widespread expression of the ghrelin receptor in the central nervous system suggests that this hormone is not only involved in metabolism, but also in other essential functions in the brain. In fact, ghrelin has been shown to promote cell survival and neuroprotection, with some studies exploring the use of ghrelin as a therapeutic agent against metabolic and neurodegenerative diseases. In this review, we highlight the possible role of glial cells as mediators of ghrelin’s actions within the brain. PMID:28257088

  3. Ghrelin administered spinally increases the blood glucose level in mice.

    Science.gov (United States)

    Sim, Yun-Beom; Park, Soo-Hyun; Kim, Sung-Su; Kim, Chea-Ha; Kim, Su-Jin; Lim, Su-Min; Jung, Jun-Sub; Suh, Hong-Won

    2014-04-01

    Ghrelin is known as a regulator of the blood glucose homeostasis and food intake. In the present study, the possible roles of ghrelin located in the spinal cord in the regulation of the blood glucose level were investigated in ICR mice. We found that intrathecal (i.t.) injection with ghrelin (from 1 to 10 μg) caused an elevation of the blood glucose level. In addition, i.t. pretreatment with YIL781 (ghrelin receptor antagonist; from 0.1 to 5 μg) markedly attenuated ghrelin-induced hyperglycemic effect. The plasma insulin level was increased by ghrelin. The enhanced plasma insulin level by ghrelin was reduced by i.t. pretreatment with YIL781. However, i.t. pretreatment with glucagon-like peptide-1 (GLP-1; 5 μg) did not affect the ghrelin-induced hyperglycemia. Furthermore, i.t. administration with ghrelin also elevated the blood glucose level, but in an additive manner, in d-glucose-fed model. Our results suggest that the activation of ghrelin receptors located in the spinal cord plays important roles for the elevation of the blood glucose level. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Induced Ablation of Ghrelin Cells in Adult Mice Does Not Decrease Food Intake, Body Weight, or Response to High Fat Diet

    Science.gov (United States)

    McFarlane, Matthew R.; Brown, Michael S.; Goldstein, Joseph L.; Zhao, Tong-Jin

    2014-01-01

    SUMMARY Injection of the peptide hormone ghrelin stimulates food intake in mice and humans. However, mice born without ghrelin demonstrate no significant loss of appetite. This paradox suggests either that compensation develops in mice born without ghrelin or that ghrelin is not essential for appetite control. To distinguish these possibilities, we generated transgenic mice (Ghrl-DTR) that express the diphtheria toxin receptor in ghrelin-secreting cells. Injection of diphtheria toxin in adulthood ablated ghrelin cells and reduced plasma ghrelin by 80-95%. Ghrelin cell-ablated mice exhibited no loss of appetite or body weight and no resistance to a high fat diet. To stimulate food intake in mice by ghrelin injection, we had to raise plasma levels many-fold above normal. Like germline ghrelin-deficient mice, the ghrelin cell-ablated mice developed profound hypoglycemia when subjected to prolonged calorie restriction, confirming that ghrelin acts to maintain blood glucose under famine conditions. PMID:24836560

  5. Genetic variation of the growth hormone secretagogue receptor gene is associated with alcohol use disorders identification test scores and smoking.

    Science.gov (United States)

    Suchankova, Petra; Nilsson, Staffan; von der Pahlen, Bettina; Santtila, Pekka; Sandnabba, Kenneth; Johansson, Ada; Jern, Patrick; Engel, Jörgen A; Jerlhag, Elisabet

    2016-03-01

    The multifaceted gut-brain peptide ghrelin and its receptor (GHSR-1a) are implicated in mechanisms regulating not only the energy balance but also the reward circuitry. In our pre-clinical models, we have shown that ghrelin increases whereas GHSR-1a antagonists decrease alcohol consumption and the motivation to consume alcohol in rodents. Moreover, ghrelin signaling is required for the rewarding properties of addictive drugs including alcohol and nicotine in rodents. Given the hereditary component underlying addictive behaviors and disorders, we sought to investigate whether single nucleotide polymorphisms (SNPs) located in the pre-proghrelin gene (GHRL) and GHSR-1a gene (GHSR) are associated with alcohol use, measured by the alcohol use disorders identification test (AUDIT) and smoking. Two SNPs located in GHRL, rs4684677 (Gln90Leu) and rs696217 (Leu72Met), and one in GHSR, rs2948694, were genotyped in a subset (n = 4161) of a Finnish population-based cohort, the Genetics of Sexuality and Aggression project. The effect of these SNPs on AUDIT scores and smoking was investigated using linear and logistic regressions, respectively. We found that the minor allele of the rs2948694 SNP was nominally associated with higher AUDIT scores (P = 0.0204, recessive model) and smoking (P = 0.0002, dominant model). Furthermore, post hoc analyses showed that this risk allele was also associated with increased likelihood of having high level of alcohol problems as determined by AUDIT scores ≥ 16 (P = 0.0043, recessive model). These convergent findings lend further support for the hypothesized involvement of ghrelin signaling in addictive disorders. © 2015 Society for the Study of Addiction.

  6. Ghrelin and its promoter variant associated with cardiac hypertrophy.

    Science.gov (United States)

    Ukkola, O; Pääkkö, T; Kesäniemi, Y A

    2012-07-01

    The roles of ghrelin, a peptide hormone that has a role in regulating food intake and energy homeostasis, in the cardiovascular system have not yet been unambiguously established. We evaluated the association between plasma ghrelin concentrations and -501A>C single-nucleotide polymorphism (SNP) in the ghrelin gene 5' flanking area and echocardiographic measurements in 1037 middle-aged subjects. Left ventricular mass index (LVMI) was calculated according to Devereux's method. The ambulatory blood pressure (BP) was recorded using the fully automatic SpaceLabs 90207 oscillometric unit. Results suggested that plasma ghrelin was not related to mean ambulatory BP values. However, the highest plasma ghrelin tertile was associated with increased intraventricular septum (P=0.043) and posterior ventricular wall (P=0.002) thicknesses as well as left ventricular mass (P=0.05). After adjustment for age, sex, body mass index and systolic BP, the association persisted between ghrelin tertiles and intraventricular septum (P=0.05) and posterior ventricular wall (P=0.001) thicknesses. The SNP -501A>C polymorphism was associated with LVMI after adjustments for age, sex and systolic BP. In conclusion, ghrelin and its promoter variant are associated with cardiac hypertrophy indexes independent of BP. Positive correlation between ghrelin levels and increased wall thickness parameters may reflect compensatory up-regulation of ghrelin concentrations or direct effects of ghrelin on myocardium. The effects of the SNP seem not to be mediated through its effects on ghrelin plasma levels.

  7. Endogenous ghrelin-O-acyltransferase (GOAT) acylates local ghrelin in the hippocampus.

    Science.gov (United States)

    Murtuza, Mohammad I; Isokawa, Masako

    2018-01-01

    Ghrelin is an appetite-stimulating peptide. Serine 3 on ghrelin must be acylated by octanoate via the enzyme ghrelin-O-acyltransferase (GOAT) for the peptide to bind and activate the cognate receptor, growth hormone secretagogue receptor type 1a (GHSR1a). Interest in GHSR1a increased dramatically when GHSR1a mRNA was demonstrated to be widespread in the brain, including the cortex and hippocampus, indicating that it has multifaceted functions beyond the regulation of metabolism. However, the source of octanoylated ghrelin for GHSR1a in the brain, outside of the hypothalamus, is not well understood. Here, we report the presence of GOAT and its ability to acylate non-octanoylated ghrelin in the hippocampus. GOAT immunoreactivity is aggregated at the base of the dentate granule cell layer in the rat and wild-type mouse. This immunoreactivity was not affected by the pharmacological inhibition of GHSR1a or the metabolic state-dependent fluctuation of systemic ghrelin levels. However, it was absent in the GHSR1a knockout mouse hippocampus, pointing the possibility that the expression of GHSR1a may be a prerequisite for the production of GOAT. Application of fluorescein isothiocyanate (FITC)-conjugated non-octanoylated ghrelin in live hippocampal slice culture (but not in fixed culture or in the presence of GOAT inhibitors) mimicked the binding profile of FITC-conjugated octanoylated ghrelin, suggesting that extracellularly applied non-octanoylated ghrelin was acylated by endogenous GOAT in the live hippocampus while GOAT being mobilized out of neurons. Our results will advance the understanding for the role of endogenous GOAT in the hippocampus and facilitate the search for the source of ghrelin that is intrinsic to the brain. © 2017 International Society for Neurochemistry.

  8. Leu72Met and Other Intronic Polymorphisms in the and Genes Are Not Associated with Type 2 Diabetes Mellitus, Insulin Resistance, or Serum Ghrelin Levels in a Saudi Population

    Directory of Open Access Journals (Sweden)

    Faris Elbahi Joatar

    2017-09-01

    Full Text Available BackgroundGhrelin (GHRL, a gastric peptide encoded by the GHRL gene, is known to be involved in energy homeostasis via its G protein receptor, encoded by the growth hormone secretagogue receptor (GHSR gene. Some studies have shown associations between plasma GHRL levels and GHRL single-nucleotide polymorphisms (SNPs, namely the Leu72Met polymorphism (rs696217 TG, with type 2 diabetes mellitus (T2DM and insulin resistance (IR, while others have not. The controversies in these associations raise the issue of ‘which SNPs in which populations.’ The aim of this study was to investigate whether SNPs in GHRL and/or GHSR genes were associated with T2DM, IR, or plasma GHRL levels among Arab Saudis.MethodsBlood was collected from 208 Saudi subjects with (n=107 and without (n=101 T2DM. DNA samples from these subjects were analyzed by real-time polymerase chain reaction to genotype five intronic SNPs in the GHRL (rs696217 TG, rs27647 CT, rs2075356 CT, and rs4684677 AT and GHSR (rs509030 GC genes. In addition, plasma GHRL levels were measured by a radioimmunoassay.ResultsNone of the SNPs were associated with T2DM, IR, or plasma GHRL levels. The frequencies of the alleles, genotypes, and haplotypes of the five SNPs were comparable between the T2DM patients and the non-diabetic subjects. A large number of the GHRL haplotypes indicates the molecular heterogeneity of the preproghrelin gene in this region.ConclusionNeither the Leu72Met polymorphism nor the other intronic GHRL and GHSR SNPs were associated with T2DM, IR, or GHRL levels. Further investigations should be carried out to explain the molecular basis of the association of the GHRL peptide with T2DM and IR.

  9. Leu72Met and Other Intronic Polymorphisms in the GHRL and GHSR Genes Are Not Associated with Type 2 Diabetes Mellitus, Insulin Resistance, or Serum Ghrelin Levels in a Saudi Population.

    Science.gov (United States)

    Joatar, Faris Elbahi; Al Qarni, Ali Ahmed; Ali, Muhalab E; Al Masaud, Abdulaziz; Shire, Abdirashid M; Das, Nagalla; Gumaa, Khalid; Giha, Hayder A

    2017-09-01

    Ghrelin (GHRL), a gastric peptide encoded by the GHRL gene, is known to be involved in energy homeostasis via its G protein receptor, encoded by the growth hormone secretagogue receptor (GHSR) gene. Some studies have shown associations between plasma GHRL levels and GHRL single-nucleotide polymorphisms (SNPs), namely the Leu72Met polymorphism (rs696217 TG), with type 2 diabetes mellitus (T2DM) and insulin resistance (IR), while others have not. The controversies in these associations raise the issue of 'which SNPs in which populations.' The aim of this study was to investigate whether SNPs in GHRL and/or GHSR genes were associated with T2DM, IR, or plasma GHRL levels among Arab Saudis. Blood was collected from 208 Saudi subjects with (n=107) and without (n=101) T2DM. DNA samples from these subjects were analyzed by real-time polymerase chain reaction to genotype five intronic SNPs in the GHRL (rs696217 TG, rs27647 CT, rs2075356 CT, and rs4684677 AT) and GHSR (rs509030 GC) genes. In addition, plasma GHRL levels were measured by a radioimmunoassay. None of the SNPs were associated with T2DM, IR, or plasma GHRL levels. The frequencies of the alleles, genotypes, and haplotypes of the five SNPs were comparable between the T2DM patients and the non-diabetic subjects. A large number of the GHRL haplotypes indicates the molecular heterogeneity of the preproghrelin gene in this region. Neither the Leu72Met polymorphism nor the other intronic GHRL and GHSR SNPs were associated with T2DM, IR, or GHRL levels. Further investigations should be carried out to explain the molecular basis of the association of the GHRL peptide with T2DM and IR. Copyright © 2017 Korean Endocrine Society

  10. Ghrelin in the regulation of body weight and metabolism.

    Science.gov (United States)

    Castañeda, T R; Tong, J; Datta, R; Culler, M; Tschöp, M H

    2010-01-01

    Ghrelin, a peptide hormone predominantly produced by the stomach, was isolated as the endogenous ligand for the growth hormone secretagogue receptor. Ghrelin is a potent stimulator of growth hormone (GH) secretion and is the only circulatory hormone known to potently enhance feeding and weight gain and to regulate energy homeostasis following central and systemic administration. Therapeutic intervention with ghrelin in catabolic situations may induce a combination of enhanced food intake, increased gastric emptying and nutrient storage, coupled with an increase in GH thereby linking nutrient partitioning with growth and repair processes. These qualities have fostered the idea that ghrelin-based compounds may have therapeutic utility in treating malnutrition and wasting induced by various sub-acute and chronic disorders. Conversely, compounds that inhibit ghrelin action may be useful for the prevention or treatment of metabolic syndrome components such as obesity, impaired lipid metabolism or insulin resistance. In recent years, the effects of ghrelin on glucose homeostasis, memory function and gastrointestinal motility have attracted considerable amount of attention and revealed novel therapeutic targets in treating a wide range of pathologic conditions. Furthermore, discovery of ghrelin O-acyltransferase has also opened new research opportunities that could lead to major understanding of ghrelin physiology. This review summarizes the current knowledge on ghrelin synthesis, secretion, mechanism of action and biological functions with an additional focus on potential for ghrelin-based pharmacotherapies. 2009 Elsevier Inc. All rights reserved.

  11. Leu72Met408 Polymorphism of the Ghrelin Gene Is Associated With Early Phase of Gastric Emptying in the Patients With Functional Dyspepsia in Japan.

    Science.gov (United States)

    Yamawaki, Hiroshi; Futagami, Seiji; Shimpuku, Mayumi; Shindo, Tomotaka; Maruki, Yuuta; Nagoya, Hiroyuki; Kodaka, Yasuhiro; Sato, Hitomi; Gudis, Katya; Kawagoe, Tetsuro; Sakamoto, Choitsu

    2015-01-01

    There are no available data about the relationship between ghrelin gene genotypes and early phase of gastric emptying in functional dyspepsia (FD) as defined by Rome III classification. We enrolled 74 patients presenting with typical symptoms of FD and 64 healthy volunteers. Gastric motility was evaluated using the 13C-acetate breath test. We used Rome III criteria to evaluate upper abdominal symptoms and self-rating questionnaires for depression (SRQ-D) scores to determine status of depression. The Arg51Gln (346G->A), preproghrelin (3056T->C), Leu72Met (408C->A), Gln90Leu (3412T->A) and G-protein 3 (825C->T) polymorphisms were analyzed in the DNA from blood samples of enrolled subjects. Genotyping was performed by polymerase chain reaction. There was a significant relationship between the Gln90Leu3412 genotype and SRQ-D score in FD patients (P = 0.009). Area under the curve at 15 minutes (AUC15) value was significantly associated with the Leu72Met408 genotype (P = 0.015) but not with entire gastric emptying. The Leu72Met (408C->A) single nucleotide polymorphism was significantly associated with early phase of gastric emptying in FD patients. Further studies will be necessary to clarify the association between ghrelin gene single nucleotide polymorphisms and early phase of gastric emptying in FD patients.

  12. Glucagon-like peptide 2 inhibits ghrelin secretion in humans

    DEFF Research Database (Denmark)

    Banasch, Matthias; Bulut, Kerem; Hagemann, Dirk

    2006-01-01

    INTRODUCTION: The growth hormone secretagogue receptor ligand ghrelin is known to play a pivotal role in the central nervous control of energy homeostasis. Circulating ghrelin levels are high under fasting conditions and decline after meal ingestion, but the mechanisms underlying the postprandial...... drop in ghrelin levels are poorly understood. In the present study we addressed, whether (1) exogenous GLP-2 administration decreases ghrelin levels and (2) what other endogenous factors are related to ghrelin secretion under fasting conditions. PATIENTS AND METHODS: Fifteen healthy male volunteers...... were studied with the intravenous infusion of GLP-2 (2 pmol l(-1) min(-1)) or placebo over 120 min in the fasting state. Plasma concentrations of glucose, insulin, C-peptide, glucagon, intact GLP-2 and ghrelin were determined. RESULTS: During the infusion of GLP-2, plasma concentrations of intact GLP-2...

  13. Ghrelin differentially affects hepatic and peripheral insulin sensitivity in mice

    NARCIS (Netherlands)

    Heijboer, A. C.; van den Hoek, A. M.; Parlevliet, E. T.; Havekes, L. M.; Romijn, J. A.; Pijl, H.; Corssmit, E. P. M.

    2006-01-01

    This study was conducted to evaluate the effects of ghrelin on insulin's capacity to suppress endogenous glucose production and promote glucose disposal in mice. To establish whether the growth hormone secretagogue (GHS) receptor can mediate the putative effect of ghrelin on the action of insulin,

  14. Ghrelin differentially affects hepatic and peripheral insulin sensitivity in mice

    NARCIS (Netherlands)

    Heijboer, A.C.; Hoek, A.M. van den; Parlevliet, E.T.; Havekes, L.M.; Romijn, J.A.; Pijl, H.; Corssmit, E.P.M.

    2006-01-01

    Aims/hypothesis: This study was conducted to evaluate the effects of ghrelin on insulin's capacity to suppress endogenous glucose production and promote glucose disposal in mice. To establish whether the growth hormone secretagogue (GHS) receptor can mediate the putative effect of ghrelin on the

  15. Ghrelin: Expression and Functions in the Central Nervous System

    NARCIS (Netherlands)

    Stoyanova, Irina; Yamada, H.; Takahashi, K.

    2011-01-01

    Ghrelin is a gastric peptide hormone and neurotransmitter, ligand for the growth hormone secretagogue receptor (GHS-R1). The hypothalamus was identified as the main source of ghrelin in the CNS, therefore the effects of the peptide have been mainly related to this part of the brain; numerous studies

  16. Glucose-mediated control of ghrelin release from primary cultures of gastric mucosal cells

    Science.gov (United States)

    Sakata, Ichiro; Park, Won-Mee; Walker, Angela K.; Piper, Paul K.; Chuang, Jen-Chieh; Osborne-Lawrence, Sherri

    2012-01-01

    The peptide hormone ghrelin is released from a distinct group of gastrointestinal cells in response to caloric restriction, whereas its levels fall after eating. The mechanisms by which ghrelin secretion is regulated remain largely unknown. Here, we have used primary cultures of mouse gastric mucosal cells to investigate ghrelin secretion, with an emphasis on the role of glucose. Ghrelin secretion from these cells upon exposure to different d-glucose concentrations, the glucose antimetabolite 2-deoxy-d-glucose, and other potential secretagogues was assessed. The expression profile of proteins involved in glucose transport, metabolism, and utilization within highly enriched pools of mouse ghrelin cells and within cultured ghrelinoma cells was also determined. Ghrelin release negatively correlated with d-glucose concentration. Insulin blocked ghrelin release, but only in a low d-glucose environment. 2-Deoxy-d-glucose prevented the inhibitory effect of high d-glucose exposure on ghrelin release. mRNAs encoding several facilitative glucose transporters, hexokinases, the ATP-sensitive potassium channel subunit Kir6.2, and sulfonylurea type 1 receptor were expressed highly within ghrelin cells, although neither tolbutamide nor diazoxide exerted direct effects on ghrelin secretion. These findings suggest that direct exposure of ghrelin cells to low ambient d-glucose stimulates ghrelin release, whereas high d-glucose and glucose metabolism within ghrelin cells block ghrelin release. Also, low d-glucose sensitizes ghrelin cells to insulin. Various glucose transporters, channels, and enzymes that mediate glucose responsiveness in other cell types may contribute to the ghrelin cell machinery involved in regulating ghrelin secretion under these different glucose environments, although their exact roles in ghrelin release remain uncertain. PMID:22414807

  17. Chromosomal organization of adrenergic receptor genes

    International Nuclear Information System (INIS)

    Yang-Feng, T.L.; Xue, Feiyu; Zhong, Wuwei; Cotecchia, S.; Frielle, T.; Caron, M.G.; Lefkowitz, R.J.; Francke, U.

    1990-01-01

    The adrenergic receptors (ARs) (subtypes α 1 , α 2 , β 1 , and β 2 ) are a prototypic family of guanine nucleotide binding regulatory protein-coupled receptors that mediate the physiological effects of the hormone epinephrine and the neurotransmitter norepinephrine. The authors have previously assigned the genes for β 2 -and α 2 -AR to human chromosomes 5 and 10, respectively. By Southern analysis of somatic cell hybrids and in situ chromosomal hybridization, they have now mapped the α 1 -AR gene to chromosome 5q32→q34, the same position as β 2 -AR, and the β 1 -AR gene to chromosome 10q24→q26, the region where α 2 -AR, is located. In mouse, both α 2 -and β 1 -AR genes were assigned to chromosome 19, and the α 1 -AR locus was localized to chromosome 11. Pulsed field gel electrophoresis has shown that the α 1 -and β 2 -AR genes in humans are within 300 kilobases (kb) and the distance between the α 2 - and β 1 -AR genes is <225 kb. The proximity of these two pairs of AR genes and the sequence similarity that exists among all the ARs strongly suggest that they are evolutionarily related. Moreover, they likely arose from a common ancestral receptor gene and subsequently diverged through gene duplication and chromosomal duplication to perform their distinctive roles in mediation the physiological effects of catecholamines. The AR genes thus provide a paradigm for understanding the evolution of such structurally conserved yet functionally divergent families off receptor molecules

  18. Novel regulator of acylated ghrelin, CF801, reduces weight gain, rebound feeding after a fast, and adiposity in mice

    Directory of Open Access Journals (Sweden)

    Martin K Wellman

    2015-09-01

    Full Text Available Ghrelin is a 28 amino-acid hormonal peptide that is intimately related to the regulation of food intake and body weight. Once secreted, ghrelin binds to the growth hormone secretagogue receptor-1a (GHSR-1a, the only known receptor for ghrelin and is capable of activating a number of signaling cascades ultimately resulting in an increase in food intake and adiposity. Because ghrelin has been linked to overeating and the development of obesity, a number of pharmacological interventions have been generated in order to interfere with either the activation of ghrelin or interrupting ghrelin signaling as a means to reducing appetite and decrease weight gain. Here we present a novel peptide, CF801, capable of reducing circulating acylated ghrelin levels and subsequent body weight gain and adiposity. To this end, we show that IP administration of CF801 is sufficient to reduce circulating plasma acylated ghrelin levels. Acutely, intraperitoneal injections of CF801 resulted in decreased rebound feeding after an overnight fast. When delivered chronically decreased weight gain and adiposity without affecting caloric intake. CF801, however, did cause a change in diet preference, decreasing preference for a high fat diet and increasing preference for regular chow diet. Given the complexity of ghrelin receptor function, we propose that CF801 along with other compounds that regulate ghrelin secretion may prove to be a beneficial tool in the study of the ghrelin system, and potential targets for ghrelin based obesity treatments without altering the function of ghrelin receptors.

  19. Ghrelin and Neurodegenerative Disorders-a Review.

    Science.gov (United States)

    Shi, Limin; Du, Xixun; Jiang, Hong; Xie, Junxia

    2017-03-01

    Ghrelin, the endogenous ligand of the growth hormone secretagogue receptor 1a (GHS-R1a), is a gut-derived, orexigenic peptide hormone that primarily regulates growth hormone secretion, food intake, and energy homeostasis. With the wide expression of GHS-R1a in extra-hypothalamic regions, the physiological role of ghrelin is more extensive than solely its involvement in metabolic function. Ghrelin has been shown to be involved in numerous higher brain functions, such as memory, reward, mood, and sleep. Some of these functions are disrupted in neurodegenerative disorders, including Parkinson's disease (PD), Alzheimer's disease (AD), and Huntington's disease (HD). This link between ghrelin and these neurodegenerative diseases is supported by numerous studies. This review aims to provide a comprehensive overview of the most recent evidence of the novel neuromodulatory role of ghrelin in PD, AD, and HD. Moreover, the changes in circulating and/or central ghrelin levels that are associated with disease progression are also postulated to be a biomarker for clinical diagnosis and therapy.

  20. Structural determination, distribution, and physiological actions of ghrelin in the guinea pig.

    Science.gov (United States)

    Okuhara, Yuji; Kaiya, Hiroyuki; Teraoka, Hiroki; Kitazawa, Takio

    2018-01-01

    We identified guinea pig ghrelin (gp-ghrelin), and examined its distribution and physiological actions in the guinea-pig. Gp-ghrelin is a 28-amino acid peptide (GASFR SPEHH SAQQR KESRK LPAKI QPR); seven amino acids are different from that of rat ghrelin at positions 2, 5, 10, 11, 19, 21, and 25, which include the conserved region known in mammals. The third serine residue is mainly modified by n-decanoyl acid. Both gp-ghrelin and rat ghrelin increased intracellular Ca 2+ concentration of HEK293 cells expressing guinea pig growth hormone secretagogue receptor 1a (GHS-R1a), and the affinity of gp-ghrelin was slightly higher than that of rat ghrelin. In addition, gp-ghrelin was also effective in CHO cells expressing rat GHS-R1a with similar affinity to that of rat ghrelin. Gp-ghrelin mRNA was predominantly expressed in the stomach, whereas the expression levels in other organs was low. High levels of GHS-R1a mRNA expression were observed in the pituitary, medulla oblongata, and kidney, while medium levels were noted in the thalamus, pons, olfactory bulb, and heart. Immunohistochemistry identified gp-ghrelin-immunopositive cells in the gastric mucosa and pancreas. Intraperitoneal injection of gp-ghrelin increased food intake in the guinea pig. Gp-ghrelin did not cause any mechanical responses in isolated gastrointestinal smooth muscles in vitro, similar to rat ghrelin. In conclusion, the N-terminal structures that are conserved in mammals were different in gp-ghrelin. Moreover, the functional characteristics of gp-ghrelin, other than its distribution, were dissimilar from those in other Rodentia. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Ghrelin plasma levels in patients with idiopathic short stature.

    Science.gov (United States)

    Iñiguez, Germán; Román, Rossana; Youlton, Ronald; Cassorla, Fernando; Mericq, Verónica

    2011-02-01

    Novel molecular insights have suggested that ghrelin may be involved in the pathogenesis of some forms of short stature. Recently, growth hormone secretagogue receptor (GHSR) mutations that segregate with short stature have been reported. To study plasma ghrelin levels in prepubertal patients with idiopathic short stature (ISS). Fasting total plasma ghrelin levels (radioimmunoassay) in 41 prepubertal patients with ISS (18 females, age 7.9 ± 0.5 years) compared with 42 age- and sex-matched controls (27 females, age 8.0 ± 0.3 years) with normal height. In a subset of 28 patients, the ghrelin receptor was sequenced. ISS patients exhibited a higher level of ghrelin (1,458 ± 137 vs. 935 ± 55 pg/ml, p ghrelin levels greater than +2 SDS compared to controls. These patients did not differ in height, BMI or IGF-I SDS compared to ISS patients with ghrelin levels within the normal range. Molecular analysis of GHSR did not show any mutations, but showed some polymorphisms. These results suggest that in ISS patients, short stature does not appear to be frequently caused by abnormalities in ghrelin signaling. Copyright © 2010 S. Karger AG, Basel.

  2. Regulation of ghrelin secretion and action.

    Science.gov (United States)

    Camiña, Jesus P; Carreira, Marcos C; Micic, Dragan; Pombo, Manuel; Kelestimur, Fahrettin; Dieguez, Carlos; Casanueva, Felipe F

    2003-10-01

    The pulsatile release of growth hormone (GH) from anterior pituitary gland is regulated by the interplay of at least two hypothalamic hormones, GH-releasing hormone (GHRH) and somatostatin, via their engagement with specific cell surface receptors on the anterior pituitary somatotroph. Furthermore, release of GH in vivo may also be controlled by a third type of receptor, the growth hormone secretagogue receptor, a G-protein-coupled receptor, called GHS receptor type 1a (GHSR1a), which was identified in the pituitary and the hypothalamus in humans using a nonpeptidyl growth hormone secretagogue (MK-0677). Ghrelin, the endogenous ligand for the GHS-R1a, is a 28-amino-acid peptide isolated from human stomach that is modified by a straight chain octanoyl group covalently linked to Ser3, which is essential for its endocrine activity. This hormone, predominantly expressed and secreted by the stomach, has a dual action on GH secretion and food intake, showing interdependency between these actions. The finding that fasting and food intake, respectively, increase and decrease the secretion of ghrelin suggests that this hormone may be the bridge connecting somatic growth and body composition with energy metabolism, and appears to play a role in the alteration of energy homeostasis and body weight in pathophysiological states such as hypothyroidism and hyperthyroidism. Despite this, little is known about the intracellular signaling through which ghrelin exerts its regulatory actions. Activation of intracellular calcium mobilization is one of the earliest known cellular signals elicited by ghrelin. In HEK- 293 cells expressing the GHS-R1a, ghrelin induces a biphasic cytosolic calcium elevation characterized by a spike phase of the response, which reflects Ins(1,4,5)P3- dependent calcium mobilization of intracellular stores, and a sustained phase of the response, which is due to calcium influx across the plasma membrane triggered by aperture of capacitative calcium channels

  3. Family trios analysis of common polymorphisms in the obestatin/ghrelin, BDNF and AGRP genes in patients with Anorexia nervosa: association with subtype, body-mass index, severity and age of onset.

    Science.gov (United States)

    Dardennes, Roland M; Zizzari, Philippe; Tolle, Virginie; Foulon, Christine; Kipman, Amélie; Romo, Lucia; Iancu-Gontard, Dana; Boni, Claudette; Sinet, Pierre-Marie; Thérèse Bluet, Marie; Estour, Bruno; Mouren, Marie-Christine; Guelfi, Julien-Daniel; Rouillon, Frédéric; Gorwood, Philip; Epelbaum, Jacques

    2007-02-01

    Anorexia nervosa (AN) affects 0.3% of young girls with a mortality of 6%/decade and is strongly familial with genetic factors. Ghrelin is an upstream regulator of the orexigenic peptides NPY and AgRP and acts as a natural antagonist to leptin's effects on NPY/AgRP-expressing neurons, resulting in an increase in feeding and body weight. Obestatin which counteracts ghrelin action on feeding is derived from the same propeptide than ghrelin. BDNF has been involved in body weight regulation and its Val66Met polymorphism associated with AN. We therefore re-investigated the association between AN and the Leu72Met and Gln90Leu polymorphisms of the prepro-ghrelin/obestatin gene, the Ala67Thr polymorphism of AgRP and the Val66Met polymorphism of BDNF taking into account clinical subtypes (restrictive--ANR--and bingeing/purging--ANB--subtypes). Family trios study of these 4 single nucleotide polymorphisms were performed in 114 probands with AN and both their parents recruited in two specialized French centres. A transmission disequilibrium was observed for the Leu72Met SNP of the preproghrelin gene and for the Ala67Thr SNP of the AgRP gene. When stratified by clinical subtype, these two polymorphisms were preferentially transmitted for the trios with a bingeing/purging proband. An excess of transmission of the Gln90Leu72 preproghrelin/obestatin haplotype in patients with AN was observed. These results do not provide evidence for a preferential transmission of the 66Met allele of BDNF but support the hypothesis that ghrelin and AGRP polymorphisms confers susceptibility to AN. Further simultaneous analysis of genetic variants of the biological determinants of energy metabolism and feeding behaviour in very large populations should contribute to the understanding of the high degree of heritability of eating disorders and to the description of pathophysiological patterns leading to life-threatening conditions in a highly redundant system.

  4. Ghrelin; The Renown Hormone

    Directory of Open Access Journals (Sweden)

    H. Murat Bilgin

    2006-01-01

    Full Text Available Ghrelin , a 28 amino acid gastric peptide, was found to be a potent releaser of GH and in addition, actively participate in controlling energy balance and the regulation of food intake. Specifically, plasma ghrelin originates in the oxyntic gland where A-like cells exist and is secreted into the bloodstream. Lower concentrations have also been reported at various regions in the body. It is well known that ghrelin participates in the regulation of many functions in the body.

  5. A ghrelin-growth hormone axis drives stress-induced vulnerability to enhanced fear.

    Science.gov (United States)

    Meyer, R M; Burgos-Robles, A; Liu, E; Correia, S S; Goosens, K A

    2014-12-01

    Hormones in the hypothalamus-pituitary-adrenal (HPA) axis mediate many of the bodily responses to stressors, yet there is no clear relationship between the levels of these hormones and stress-associated mental illnesses such as posttraumatic stress disorder (PTSD). Therefore, other hormones are likely to be involved in this effect of stress. Here we used a rodent model of PTSD in which rats repeatedly exposed to a stressor display heightened fear learning following auditory Pavlovian fear conditioning. Our results show that stress-related increases in circulating ghrelin, a peptide hormone, are necessary and sufficient for stress-associated vulnerability to exacerbated fear learning and these actions of ghrelin occur in the amygdala. Importantly, these actions are also independent of the classic HPA stress axis. Repeated systemic administration of a ghrelin receptor agonist enhanced fear memory but did not increase either corticotropin-releasing factor (CRF) or corticosterone. Repeated intraamygdala infusion of a ghrelin receptor agonist produced a similar enhancement of fear memory. Ghrelin receptor antagonism during repeated stress abolished stress-related enhancement of fear memory without blunting stress-induced corticosterone release. We also examined links between ghrelin and growth hormone (GH), a major downstream effector of the ghrelin receptor. GH protein was upregulated in the amygdala following chronic stress, and its release from amygdala neurons was enhanced by ghrelin receptor stimulation. Virus-mediated overexpression of GH in the amygdala was also sufficient to increase fear. Finally, virus-mediated overexpression of a GH receptor antagonist was sufficient to block the fear-enhancing effects of repeated ghrelin receptor stimulation. Thus, ghrelin requires GH in the amygdala to exert fear-enhancing effects. These results suggest that ghrelin mediates a novel branch of the stress response and highlight a previously unrecognized role for ghrelin and

  6. Ghrelin knockout mice show decreased voluntary alcohol consumption and reduced ethanol-induced conditioned place preference.

    Science.gov (United States)

    Bahi, Amine; Tolle, Virginie; Fehrentz, Jean-Alain; Brunel, Luc; Martinez, Jean; Tomasetto, Catherine-Laure; Karam, Sherif M

    2013-05-01

    Recent work suggests that stomach-derived hormone ghrelin receptor (GHS-R1A) antagonism may reduce motivational aspects of ethanol intake. In the current study we hypothesized that the endogenous GHS-R1A agonist ghrelin modulates alcohol reward mechanisms. For this purpose ethanol-induced conditioned place preference (CPP), ethanol-induced locomotor stimulation and voluntary ethanol consumption in a two-bottle choice drinking paradigm were examined under conditions where ghrelin and its receptor were blocked, either using ghrelin knockout (KO) mice or the specific ghrelin receptor (GHS-R1A) antagonist "JMV2959". We showed that ghrelin KO mice displayed lower ethanol-induced CPP than their wild-type (WT) littermates. Consistently, when injected during CPP-acquisition, JMV2959 reduced CPP-expression in C57BL/6 mice. In addition, ethanol-induced locomotor stimulation was lower in ghrelin KO mice. Moreover, GHS-R1A blockade, using JMV2959, reduced alcohol-stimulated locomotion only in WT but not in ghrelin KO mice. When alcohol consumption and preference were assessed using the two-bottle choice test, both genetic deletion of ghrelin and pharmacological antagonism of the GHS-R1A (JMV2959) reduced voluntary alcohol consumption and preference. Finally, JMV2959-induced reduction of alcohol intake was only observed in WT but not in ghrelin KO mice. Taken together, these results suggest that ghrelin neurotransmission is necessary for the stimulatory effect of ethanol to occur, whereas lack of ghrelin leads to changes that reduce the voluntary intake as well as conditioned reward by ethanol. Our findings reveal a major, novel role for ghrelin in mediating ethanol behavior, and add to growing evidence that ghrelin is a key mediator of the effects of multiple abused drugs. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Desacyl Ghrelin Decreases Anxiety-like Behavior in Male Mice.

    Science.gov (United States)

    Mahbod, Parinaz; Smith, Eric P; Fitzgerald, Maureen E; Morano, Rachel L; Packard, Benjamin A; Ghosal, Sriparna; Scheimann, Jessie R; Perez-Tilve, Diego; Herman, James P; Tong, Jenny

    2018-01-01

    Ghrelin is a 28-amino acid polypeptide that regulates feeding, glucose metabolism, and emotionality (stress, anxiety, and depression). Plasma ghrelin circulates as desacyl ghrelin (DAG) or, in an acylated form, acyl ghrelin (AG), through the actions of ghrelin O-acyltransferase (GOAT), exhibiting low or high affinity, respectively, for the growth hormone secretagogue receptor (GHSR) 1a. We investigated the role of endogenous AG, DAG, and GHSR1a signaling on anxiety and stress responses using ghrelin knockout (Ghr KO), GOAT KO, and Ghsr stop-floxed (Ghsr null) mice. Behavioral and hormonal responses were tested in the elevated plus maze and light/dark (LD) box. Mice lacking both AG and DAG (Ghr KO) increased anxiety-like behaviors across tests, whereas anxiety reactions were attenuated in DAG-treated Ghr KO mice and in mice lacking AG (GOAT KO). Notably, loss of GHSR1a (Ghsr null) did not affect anxiety-like behavior in any test. Administration of AG and DAG to Ghr KO mice with lifelong ghrelin deficiency reduced anxiety-like behavior and decreased phospho-extracellular signal-regulated kinase phosphorylation in the Edinger-Westphal nucleus in wild-type mice, a site normally expressing GHSR1a and involved in stress- and anxiety-related behavior. Collectively, our data demonstrate distinct roles for endogenous AG and DAG in regulation of anxiety responses and suggest that the behavioral impact of ghrelin may be context dependent. Copyright © 2018 Endocrine Society.

  8. Ghrelin in eating disorders

    NARCIS (Netherlands)

    Yi, Chun-Xia; Heppner, Kristy; Tschöp, Matthias H.

    2011-01-01

    Ghrelin is the only known circulating hormone that acts on peripheral and central targets to increase food intake and promote adiposity. The present review focuses on the possible clinical relevance of ghrelin in the regulation of human feeding behavior in individuals with obesity and other eating

  9. The suppression of ghrelin signaling mitigates age-associated thermogenic impairment

    Science.gov (United States)

    Aging is associated with severe thermogenic impairment, which contributes to obesity and diabetes in aging. We previously reported that ablation of the ghrelin receptor, growth hormone secretagogue receptor (GHS-R), attenuates age-associated obesity and insulin resistance. Ghrelin and obestatin are ...

  10. Ghrelin increases the rewarding value of high-fat diet in an orexin-dependent manner.

    Science.gov (United States)

    Perello, Mario; Sakata, Ichiro; Birnbaum, Shari; Chuang, Jen-Chieh; Osborne-Lawrence, Sherri; Rovinsky, Sherry A; Woloszyn, Jakub; Yanagisawa, Masashi; Lutter, Michael; Zigman, Jeffrey M

    2010-05-01

    Ghrelin is a potent orexigenic hormone that likely impacts eating via several mechanisms. Here, we hypothesized that ghrelin can regulate extra homeostatic, hedonic aspects of eating behavior. In the current study, we assessed the effects of different pharmacological, physiological, and genetic models of increased ghrelin and/or ghrelin-signaling blockade on two classic behavioral tests of reward behavior: conditioned place preference (CPP) and operant conditioning. Using both CPP and operant conditioning, we found that ghrelin enhanced the rewarding value of high-fat diet (HFD) when administered to ad lib-fed mice. Conversely, wild-type mice treated with ghrelin receptor antagonist and ghrelin receptor-null mice both failed to show CPP to HFD normally observed under calorie restriction. Interestingly, neither pharmacologic nor genetic blockade of ghrelin signaling inhibited the body weight homeostasis-related, compensatory hyperphagia associated with chronic calorie restriction. Also, ghrelin's effects on HFD reward were blocked in orexin-deficient mice and wild-type mice treated with an orexin 1 receptor antagonist. Our results demonstrate an obligatory role for ghrelin in certain rewarding aspects of eating that is separate from eating associated with body weight homeostasis and that requires the presence of intact orexin signaling. Copyright 2010 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  11. Increased plasma ghrelin suppresses insulin release in wethers fed with a high-protein diet.

    Science.gov (United States)

    Takahashi, T; Sato, K; Kato, S; Yonezawa, T; Kobayashi, Y; Ohtani, Y; Ohwada, S; Aso, H; Yamaguchi, T; Roh, S G; Katoh, K

    2014-06-01

    Ghrelin is a multifunctional peptide that promotes an increase of food intake and stimulates GH secretion. Ghrelin secretion is regulated by nutritional status and nutrients. Although a high-protein (HP) diet increases plasma ghrelin secretion in mammals, the mechanisms and the roles of the elevated ghrelin concentrations due to a HP diet have not been fully established. To clarify the roles of elevated acylated ghrelin upon intake of a HP diet, we investigated the regulation of ghrelin concentrations in plasma and tissues in wethers fed with either the HP diet or the control (CNT) diet for 14 days, and examined the action of the elevated plasma ghrelin by using a ghrelin-receptor antagonist. The HP diet gradually increased the plasma acylated-ghrelin concentrations, but the CNT diet did not. Although the GH concentrations did not vary significantly across the groups, an injection of ghrelin-receptor antagonist enhanced insulin levels in circulation in the HP diet group. In the fundus region of the stomach, the ghrelin levels did not differ between the HP and CNT diet groups, whereas ghrelin O-acyltransferase mRNA levels were higher in the group fed with HP diet than those of the CNT diet group were. These results indicate that the HP diet elevated the plasma ghrelin levels by increasing its synthesis; this elevation strongly suppresses the appearance of insulin in the circulation of wethers, but it is not involved in GH secretion. Overall, our findings indicate a role of endogenous ghrelin action in secretion of insulin, which acts as a regulator after the consumption of a HP diet. © 2014 Society for Endocrinology.

  12. In1-ghrelin splicing variant is overexpressed in pituitary adenomas and increases their aggressive features

    Science.gov (United States)

    Ibáñez-Costa, Alejandro; Gahete, Manuel D.; Rivero-Cortés, Esther; Rincón-Fernández, David; Nelson, Richard; Beltrán, Manuel; de la Riva, Andrés; Japón, Miguel A.; Venegas-Moreno, Eva; Gálvez, Ma Ángeles; García-Arnés, Juan A.; Soto-Moreno, Alfonso; Morgan, Jennifer; Tsomaia, Natia; Culler, Michael D.; Dieguez, Carlos; Castaño, Justo P.; Luque, Raúl M.

    2015-01-01

    Pituitary adenomas comprise a heterogeneous subset of pathologies causing serious comorbidities, which would benefit from identification of novel, common molecular/cellular biomarkers and therapeutic targets. The ghrelin system has been linked to development of certain endocrine-related cancers. Systematic analysis of the presence and functional implications of some components of the ghrelin system, including native ghrelin, receptors and the recently discovered splicing variant In1-ghrelin, in human normal pituitaries (n = 11) and pituitary adenomas (n = 169) revealed that expression pattern of ghrelin system suffers a clear alteration in pituitary adenomasas comparedwith normal pituitary, where In1-ghrelin is markedly overexpressed. Interestingly, in cultured pituitary adenoma cells In1-ghrelin treatment (acylated peptides at 100 nM; 24–72 h) increased GH and ACTH secretion, Ca2+ and ERK1/2 signaling and cell viability, whereas In1-ghrelin silencing (using a specific siRNA; 100 nM) reduced cell viability. These results indicate that an alteration of the ghrelin system, specially its In1-ghrelin variant, could contribute to pathogenesis of different pituitary adenomas types, and suggest that this variant and its related ghrelin system could provide new tools to identify novel, more general diagnostic, prognostic and potential therapeutic targets in pituitary tumors. PMID:25737012

  13. Polymorphisms in the vitamin D receptor gene and the androgen receptor gene and the risk of benign prostatic hyperplasia

    NARCIS (Netherlands)

    Bousema, J. T.; Bussemakers, M. J.; van Houwelingen, K. P.; Debruyne, F. M.; Verbeek, A. L.; de la Rosette, J. J.; Kiemeney, L. A.

    2000-01-01

    Little is known about risk factors for the development of benign prostatic hyperplasia (BPH). Recently, associations were observed between prostate cancer (CaP) risk and polymorphisms in the vitamin D receptor (VDR) gene and the androgen receptor (AR) gene. Since both receptors are relevant for

  14. Neonatal overfeeding disrupts pituitary ghrelin signalling in female rats long-term; Implications for the stress response.

    Science.gov (United States)

    Sominsky, Luba; Ziko, Ilvana; Spencer, Sarah J

    2017-01-01

    The hypothalamic-pituitary-adrenal (HPA) axis responses to psychological stress are exacerbated in adult female but not male rats made obese due to overfeeding in early life. Ghrelin, traditionally known for its role in energy homeostasis, has been recently recognised for its role in coordinating the HPA responses to stress, particularly by acting directly at the anterior pituitary where the growth hormone secretagogue receptor (GHSR), the receptor for acyl ghrelin, is abundantly expressed. We therefore hypothesised that neonatal overfeeding in female rats would compromise pituitary responsiveness to ghrelin, contributing to a hyperactive central stress responsiveness. Unlike in males where hypothalamic ghrelin signalling is compromised by neonatal overfeeding, there was no effect of early life diet on circulating ghrelin or hypothalamic ghrelin signalling in females, indicating hypothalamic feeding and metabolic ghrelin circuitry remains intact. However, neonatal overfeeding did lead to long-term alterations in the pituitary ghrelin system. The neonatally overfed females had increased neonatal and reduced adult expression of GHSR and ghrelin-O-acyl transferase (GOAT) in the pituitary as well as reduced pituitary responsiveness to exogenous acyl ghrelin-induced adrenocorticotropic hormone (ACTH) release in vitro. These data suggest that neonatal overfeeding dysregulates pituitary ghrelin signalling long-term in females, potentially accounting for the hyper-responsive HPA axis in these animals. These findings have implications for how females may respond to stress throughout life, suggesting the way ghrelin modifies the stress response at the level of the pituitary may be less efficient in the neonatally overfed.

  15. Focus on the short- and long-term effects of ghrelin on energy homeostasis.

    Science.gov (United States)

    De Vriese, Carine; Perret, Jason; Delporte, Christine

    2010-06-01

    The endogenous ligand for the growth hormone secretagogue receptor, ghrelin, is a 28-amino-acid peptide acylated with an octanoyl group at the serine in position 3. Most of the circulating ghrelin results from its synthesis and secretion by the X/A-like endocrine cells from the stomach and proximal small intestine. Besides its potent growth hormone secretory action, ghrelin is a highly pleiotropic hormone, contributing significantly to the regulation of appetite and food intake control, gastrointestinal motility, gastric acid secretion, endocrine and exocrine pancreatic secretions, cell proliferation, glucose and lipid metabolism, and cardiovascular and immunologic processes. The purpose of this review is to consider the orexigenic effects of ghrelin on short-term regulation of food intake and long-term regulation of body weight, the implications of genetic ghrelin and growth hormone secretagogue receptor polymorphism, and the use of antagonists and agonists of ghrelin in pathophysiological conditions. Copyright 2010 Elsevier Inc. All rights reserved.

  16. Prevention of diet-induced obesity by safflower oil: insights at the levels of PPARalpha, orexin, and ghrelin gene expression of adipocytes in mice.

    Science.gov (United States)

    Zhang, Zhong; Li, Qiang; Liu, Fengchen; Sun, Yuqian; Zhang, Jinchao

    2010-03-15

    The aim of this study was to investigate the prevention of diet-induced obesity by a high safflower oil diet and adipocytic gene expression in mice. Forty 3-week-old C57BL/6 mice were randomly divided into three groups: control group (CON, 5% lard + 5% safflower oil), high lard group (LAR, 45% lard + 5% safflower oil), and high safflower oil group (SAF, 45% safflower oil + 5% lard). After 10 weeks, 10 mice of the LAR group were switched to high safflower oil diet (LAR-SAF). Ten weeks later, glucose tolerance tests were performed by intraperitoneal injection of glucose. Circulating levels of lipid and insulin were measured and white adipose tissues were taken for gene chip and reverse transcriptase-polymerase chain reaction analysis. The LAR group showed higher body weight, adiposity index, insulin, and lipids than the CON group (P<0.05). The body weight in the LAR-SAF group decreased after dietary reversal. The plasma biochemical profiles decreased in the LAR-SAF and SAF groups (P<0.05) compared with those of the LAR group. The blood glucose level of the LAR-SAF group was reduced during intraperitoneal glucose tolerance test compared with that of the LAR group. The LAR-SAF group had lower levels of Orexin and Ghrelin gene expression, whereas the level of PPARalpha gene expression was significantly enhanced compared with that of the LAR group. So, the SAF diet can alter adipocytic adiposity-related gene expression and result in effective amelioration of diet-induced obesity.

  17. The Androgen Receptor Gene Mutations Database.

    Science.gov (United States)

    Gottlieb, B; Lehvaslaiho, H; Beitel, L K; Lumbroso, R; Pinsky, L; Trifiro, M

    1998-01-01

    The current version of the androgen receptor (AR) gene mutations database is described. The total number of reported mutations has risen from 272 to 309 in the past year. We have expanded the database: (i) by giving each entry an accession number; (ii) by adding information on the length of polymorphic polyglutamine (polyGln) and polyglycine (polyGly) tracts in exon 1; (iii) by adding information on large gene deletions; (iv) by providing a direct link with a completely searchable database (courtesy EMBL-European Bioinformatics Institute). The addition of the exon 1 polymorphisms is discussed in light of their possible relevance as markers for predisposition to prostate or breast cancer. The database is also available on the internet (http://www.mcgill. ca/androgendb/ ), from EMBL-European Bioinformatics Institute (ftp. ebi.ac.uk/pub/databases/androgen ), or as a Macintosh FilemakerPro or Word file (MC33@musica.mcgill.ca).

  18. Ghrelin: an emerging player in the regulation of reproduction in non-mammalian vertebrates.

    Science.gov (United States)

    Unniappan, Suraj

    2010-07-01

    The endocrine regulation of vertebrate reproduction is achieved by the coordinated actions of multiple endocrine factors mainly produced from the brain, pituitary, and gonads. In addition to these, several other tissues including the fat and gut produce factors that have reproductive effects. Ghrelin is one such gut/brain hormone with species-specific effects in the regulation of mammalian reproduction. Recent studies have shown that ghrelin and ghrelin receptor mRNAs, and protein are expressed in the ovary and testis of mammals, indicating a direct effect for ghrelin in the control of reproduction. Ghrelin regulates mammalian reproduction by modulating hormone secretion from the brain and pituitary, and by acting directly on the gonads to influence reproductive tissue development and steroid hormone release. Based on the studies reported so far, ghrelin seems to have a predominantly inhibitory role on mammalian reproduction. The presence of ghrelin and ghrelin receptor has been found in the brain, pituitary and gonads of several non-mammalian vertebrates. In contrast to mammals, ghrelin seems to have a stimulatory role in the regulation of non-mammalian reproduction. The main objective of this review is to do a perspective analysis of the comparative aspects of ghrelin regulation of reproduction. (c) 2009 Elsevier Inc. All rights reserved.

  19. Fasting up-regulates ferroportin 1 expression via a Ghrelin/GHSR/MAPK signaling pathway.

    Science.gov (United States)

    Luo, Qian-Qian; Zhou, Yu-Fu; Chen, Mesona Yung-Jin; Liu, Li; Ma, Juan; Zhang, Meng-Wan; Zhang, Fa-Li; Ke, Ya; Qian, Zhong-Ming

    2018-01-01

    The significant positive correlation between ghrelin and iron and hepcidin levels in the plasma of children with iron deficiency anemia prompted us to hypothesize that ghrelin may affect iron metabolism. Here, we investigated the effects of fasting or ghrelin on the expression of hepcidin, ferroportin 1 (Fpn1), transferrin receptor 1 (TfR1), ferritin light chain (Ft-L) proteins, and ghrelin, and also hormone secretagogue receptor 1 alpha (GHSR1α) and ghrelin O-acyltransferase (GOAT) mRNAs in the spleen and/or macrophage. We demonstrated that fasting induces a significant increase in the expression of ghrelin, GHSR1α, GOAT, and hepcidin mRNAs, as well as Ft-L and Fpn1 but not TfR1 proteins in the spleens of mice in vivo. Similar to the effects of fasting on the spleen, ghrelin induced a significant increase in the expression of Ft-L and Fpn1 but not TfR1 proteins in macrophages in vitro. In addition, ghrelin was found to induce a significant enhancement in phosphorylation of ERK as well as translocation of pERK from the cytosol to nuclei. Furthermore, the increased pERK and Fpn1 induced by ghrelin was demonstrated to be preventable by pre-treatment with either GHSR1α antagonist or pERK inhibitor. Our findings support the hypothesis that fasting upregulates Fpn1 expression, probably via a ghrelin/GHSR/MAPK signaling pathway. © 2017 Wiley Periodicals, Inc.

  20. Ghrelin stimulates angiogenesis in human microvascular endothelial cells: Implications beyond GH release

    International Nuclear Information System (INIS)

    Li Aihua; Cheng Guangli; Zhu Genghui; Tarnawski, Andrzej S.

    2007-01-01

    Ghrelin, a peptide hormone isolated from the stomach, releases growth hormone and stimulates appetite. Ghrelin is also expressed in pancreas, kidneys, cardiovascular system and in endothelial cells. The precise role of ghrelin in endothelial cell functions remains unknown. We examined the expression of ghrelin and its receptor (GHSR1) mRNAs and proteins in human microvascular endothelial cells (HMVEC) and determined whether ghrelin affects in these cells proliferation, migration and in vitro angiogenesis; and whether MAPK/ERK2 signaling is important for the latter action. We found that ghrelin and GHSR1 are constitutively expressed in HMVEC. Treatment of HMVEC with exogenous ghrelin significantly increased in these cells proliferation, migration, in vitro angiogenesis and ERK2 phosphorylation. MEK/ERK2 inhibitor, PD 98059 abolished ghrelin-induced in vitro angiogenesis. This is First demonstration that ghrelin and its receptor are expressed in human microvascular endothelial cells and that ghrelin stimulates HMVEC proliferation, migration, and angiogenesis through activation of ERK2 signaling

  1. High plasma ghrelin protects from coronary heart disease and Leu72Leu polymorphism of ghrelin gene from cancer in healthy adults during the 19 years follow-up study.

    Science.gov (United States)

    Laurila, M; Santaniemi, M; Kesäniemi, Y A; Ukkola, O

    2014-11-01

    The aim of our investigation was to find out if ghrelin concentrations or polymorphisms predict the future risk for cardiovascular diseases and cancer in a population-based cohort initiated in 1991 (491 hypertensive and 513 control subjects). Total mortality and hospital events were followed up for 19 years. Fasting total ghrelin concentrations were determined and Arg51Gln, Leu72Met and -501 A > C polymorphisms identified. Cox regression analysis was performed. The mean value in the control cohort was 674 pg/ml whereas in the hypertensive cohort it was 661 pg/ml. The associations found suggest that in the controls the highest ghrelin quartile protected from CHD (coronary heart disease). The results were significant without or with adjustments for age, sex, smoking, systolic blood pressure and LDL cholesterol, BMI, type 2 diabetes or QUICK index. C/C variant of the promoter associated with the prevention of IHD (ischemic heart disease) in the hypertensive group (pghrelin concentration was related to protection from CHD and Leu72Leu genotype to prevention of cancer in healthy adults during the 19 years follow-up. C/C promoter protects from IHD in the hypertensive subjects. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Ghrelin system in alcohol-dependent subjects: role of plasma ghrelin levels in alcohol drinking and craving.

    Science.gov (United States)

    Leggio, Lorenzo; Ferrulli, Anna; Cardone, Silvia; Nesci, Antonio; Miceli, Antonio; Malandrino, Noemi; Capristo, Esmeralda; Canestrelli, Benedetta; Monteleone, Palmiero; Kenna, George A; Swift, Robert M; Addolorato, Giovanni

    2012-03-01

    Animal studies suggest that the gut-brain peptide ghrelin plays an important role in the neurobiology of alcohol dependence (AD). Human studies show an effect of alcohol on ghrelin levels and a correlation between ghrelin levels and alcohol craving in alcoholics. This investigation consisted of two studies. Study 1 was a 12-week study with alcohol-dependent subjects, where plasma ghrelin determinations were assessed four times (T0-T3) and related to alcohol intake and craving [Penn Alcohol Craving Score (PACS) and Obsessive Compulsive Drinking Scale (OCDS)]. Serum growth hormone levels and assessment of the nutritional/metabolic status were also performed. Study 2 was a pilot case-control study to assess ghrelin gene polymorphisms (Arg51Gln and Leu72Met) in alcohol-dependent individuals. Study 1 showed no significant differences in ghrelin levels in the whole sample, while there was a statistical difference for ghrelin between non-abstinent and abstinent subjects. Baseline ghrelin levels were significantly and positively correlated with the PACS score at T1 and with all craving scores both at T2 and T3 (PACS, OCDS, obsessive and compulsive OCDS subscores). In Study 2, although there was a higher frequency of the Leu72Met ghrelin gene polymorphism in alcohol-dependent individuals, the distribution between healthy controls and alcohol dependent individuals was not statistically significant. This investigation suggests that ghrelin is potentially able to affect alcohol-seeking behaviors, such as alcohol drinking and craving, representing a new potential neuropharmacological target for AD. © 2011 The Authors, Addiction Biology © 2011 Society for the Study of Addiction.

  3. Lacto-ghrestatin, a novel bovine milk-derived peptide, suppresses ghrelin secretion.

    Science.gov (United States)

    Aoki, Hayato; Nakato, Junya; Mizushige, Takafumi; Iwakura, Hiroshi; Sato, Masaru; Suzuki, Hideyuki; Kanamoto, Ryuhei; Ohinata, Kousaku

    2017-07-01

    Ghrelin, an endogenous peptide isolated from the stomach, is known to stimulate food intake after peripheral administration. We found that the enzymatic digest of β-lactoglobulin decreases ghrelin secretion from the ghrelin-producing cell line MGN3-1. The peptides present in the digest were comprehensively analyzed using the nanoLC-OrbitrapMS. Among them, we identified that the nonapeptide LIVTQTMKG, corresponding to β-lactoglobulin(1-9), suppresses ghrelin secretion from MGN3-1 cells. We named LIVTQTMKG 'lacto-ghrestatin'. We found that lacto-ghrestatin decreases intracellular cAMP levels and mRNA expression levels of ghrelin production-related genes in MGN3-1 cells. Orally administered lacto-ghrestatin decreases plasma ghrelin levels and food intake in fasted mice. Lacto-ghrestatin is the first food-derived peptide to suppress ghrelin secretion in vitro and in vivo. © 2017 Federation of European Biochemical Societies.

  4. Transitional change in rat fetal cell proliferation in response to ghrelin and des-acyl ghrelin during the last stage of pregnancy

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Yoshiyuki; Nakahara, Keiko [Department of Veterinary Physiology, Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2192 (Japan); Kangawa, Kenji [Department of Biochemistry, National Cardiovascular Center Research Institute, Fujishirodai 5-7-1, Suita, Osaka 565-8565 (Japan); Murakami, Noboru, E-mail: a0d201u@cc.miyazaki-u.ac.jp [Department of Veterinary Physiology, Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2192 (Japan)

    2010-03-12

    Expression of mRNA for the ghrelin receptor, GHS-R1a, was detected in various peripheral and central tissues of fetal rats, including skin, bone, heart, liver, gut, brain and spinal cord, on embryonic day (ED)15 and ED17. However, its expression in skin, bone, heart and liver, but not in gut, brain and spinal cord, became relatively weak on ED19 and disappeared after birth (ND2). Ghrelin and des-acyl ghrelin facilitated the proliferation of cultured fetal (ED17, 19), but not neonatal (ND2), skin cells. On the other hand, with regard to cells from the spinal cord and hypothalamus, the proliferative effect of ghrelin continued after birth, whereas the effect of des-acyl ghrelin on neurogenesis in these tissues was lost at the ED19 fetal and ND2 neonatal stages. Immunohistochemistry revealed that the cells in the hypothalamus induced to proliferate by ghrelin at the ND2 stage were positive for nestin and glial fibrillary acidic protein. These results suggest that in the period immediately prior to, and after birth, rat fetal cells showing proliferation in response to ghrelin and des-acyl ghrelin are at a transitional stage characterized by alteration of the expression of GHS-R1a and an undefined des-acyl ghrelin receptor, their responsiveness varying among different tissues.

  5. Transitional change in rat fetal cell proliferation in response to ghrelin and des-acyl ghrelin during the last stage of pregnancy

    International Nuclear Information System (INIS)

    Inoue, Yoshiyuki; Nakahara, Keiko; Kangawa, Kenji; Murakami, Noboru

    2010-01-01

    Expression of mRNA for the ghrelin receptor, GHS-R1a, was detected in various peripheral and central tissues of fetal rats, including skin, bone, heart, liver, gut, brain and spinal cord, on embryonic day (ED)15 and ED17. However, its expression in skin, bone, heart and liver, but not in gut, brain and spinal cord, became relatively weak on ED19 and disappeared after birth (ND2). Ghrelin and des-acyl ghrelin facilitated the proliferation of cultured fetal (ED17, 19), but not neonatal (ND2), skin cells. On the other hand, with regard to cells from the spinal cord and hypothalamus, the proliferative effect of ghrelin continued after birth, whereas the effect of des-acyl ghrelin on neurogenesis in these tissues was lost at the ED19 fetal and ND2 neonatal stages. Immunohistochemistry revealed that the cells in the hypothalamus induced to proliferate by ghrelin at the ND2 stage were positive for nestin and glial fibrillary acidic protein. These results suggest that in the period immediately prior to, and after birth, rat fetal cells showing proliferation in response to ghrelin and des-acyl ghrelin are at a transitional stage characterized by alteration of the expression of GHS-R1a and an undefined des-acyl ghrelin receptor, their responsiveness varying among different tissues.

  6. Ghrelin Signalling on Food Reward: A Salient Link Between the Gut and the Mesolimbic System

    OpenAIRE

    Perello, M.; Dickson, S. L.

    2015-01-01

    ?Hunger is the best spice? is an old and wise saying that acknowledges the fact that almost any food tastes better when we are hungry. The neurobiological underpinnings of this lore include activation of the brain's reward system and the stimulation of this system by the hunger?promoting hormone ghrelin. Ghrelin is produced largely from the stomach and levels are higher preprandially. The ghrelin receptor is expressed in many brain areas important for feeding control, including not only the h...

  7. Abalation of ghrelin receptor reduces adiposity and improves insulin sensitivity during aging by regulating fat metabolism in white and brown adipose tissues

    Science.gov (United States)

    Aging is associated with increased adiposity in white adipose tissues and impaired thermogenesis in brown adipose tissues; both contribute to increased incidences of obesity and type 2 diabetes. Ghrelin is the only known circulating orexigenic hormone that promotes adiposity. In this study, we show ...

  8. Widespread ectopic expression of olfactory receptor genes

    Directory of Open Access Journals (Sweden)

    Yanai Itai

    2006-05-01

    Full Text Available Abstract Background Olfactory receptors (ORs are the largest gene family in the human genome. Although they are expected to be expressed specifically in olfactory tissues, some ectopic expression has been reported, with special emphasis on sperm and testis. The present study systematically explores the expression patterns of OR genes in a large number of tissues and assesses the potential functional implication of such ectopic expression. Results We analyzed the expression of hundreds of human and mouse OR transcripts, via EST and microarray data, in several dozens of human and mouse tissues. Different tissues had specific, relatively small OR gene subsets which had particularly high expression levels. In testis, average expression was not particularly high, and very few highly expressed genes were found, none corresponding to ORs previously implicated in sperm chemotaxis. Higher expression levels were more common for genes with a non-OR genomic neighbor. Importantly, no correlation in expression levels was detected for human-mouse orthologous pairs. Also, no significant difference in expression levels was seen between intact and pseudogenized ORs, except for the pseudogenes of subfamily 7E which has undergone a human-specific expansion. Conclusion The OR superfamily as a whole, show widespread, locus-dependent and heterogeneous expression, in agreement with a neutral or near neutral evolutionary model for transcription control. These results cannot reject the possibility that small OR subsets might play functional roles in different tissues, however considerable care should be exerted when offering a functional interpretation for ectopic OR expression based only on transcription information.

  9. Ghrelin and eating disorders

    OpenAIRE

    Fabbri,Alessandra Donzelli; Deram,Sophie; Kerr,Daniel Shikanai; Cordás,Táki Athanássios

    2015-01-01

    Background Ghrelin is a potent hormone with central and peripheral action. This hormone plays an important role in the regulation of appetite, food intake, and energy balance. Studies have suggested that ghrelin is involved with eating disorders (ED), particularly bingeing and purging. Genetic variants have also been studied to explain changes in eating behavior. Methods We conducted a literature review; we searched PubMed, Scientific Electronic Library Online (SciELO), and LILACS databases u...

  10. Examining the candidacy of ghrelin as a gene responsible for variation in adult stature in a United Kingdom population with type 2 diabetes.

    Science.gov (United States)

    Gueorguiev, Maria; Wiltshire, Steven; Garcia, Edwin A; Mein, Charles; Lecoeur, Cecile; Kristen, Brigitte; Allotey, Rebecca; Hattersley, Andrew T; Walker, Mark; O'rahilly, Stephen; Froguel, Philippe; Grossman, Ashley B; McCarthy, Mark I; Hitman, Graham A; Korbonits, Márta

    2007-06-01

    Recently, a quantitative trait locus for stature was reported on chromosome 3p26 in patients with type 2 diabetes. Given that ghrelin is a peptide involved in GH release and located on 3p26, we hypothesized that variation within its gene (GHRL) may be responsible for the quantitative trait locus on 3p26. The evidence for linkage around GHRL was refined with the genotyping of an additional four microsatellites (D3S4545, D3S1537, D3S1597, and D3S3611), giving a total of 27 markers, followed by multipoint variance components linkage analysis. Probands from the linkage families were typed for five common single nucleotide polymorphisms (SNPs) within GHRL and tested for association with adult stature using haplotype trend regression. The maximum multipoint evidence for linkage between adult stature and the 27 microsatellites yielded an LOD score of 2.58 (P = 0.0003) between D3S1297 and D3S1304. Five common (frequency of > or =5%) SNPs were typed in the probands [two promoter SNPs (rs27647 and rs26802), two exonic (rs696217 and rs4684677), and one intronic (rs35683)] capturing 80% of the total common variation in GHRL. No association was found between any SNP (or haplotypes thereof) and adult stature. Common genetic variation within GHRL is not responsible for variation in adult stature in this population.

  11. Effect of polymorphisms at the ghrelin gene locus on carcass, microstructure and physicochemical properties of longissimus lumborum muscle of Polish Landrace pigs.

    Science.gov (United States)

    Wojtysiak, Dorota; Kaczor, Urszula

    2011-12-01

    The influence of RFLP-BsrI polymorphisms at the ghrelin gene locus on carcass, meat quality parameters and muscle fiber characteristics of longissimus lumborum was studied in 168 barrows of the Polish Landrace breed. Analysis revealed a high frequency of the 1 allele (0.60) with the frequencies of the 11, 12 and 22 genotypes being 0.45, 0.30 and 0.25, respectively. The most favorable parameters of meat traits were characteristic of pigs with the 22 genotype, together with a higher carcass and loin weight and lower thermal loss compared to 12 heterozygotes. The highest fat content was found in pigs with the 11 genotype, which had the highest abdominal fat weight and mean backfat thickness. Meanwhile, the 12 heterozygotes were characterized by the largest loin eye areas, highest lightness (L*) and yellowness (b*) values, and lowest redness (a*) values, as well as the greatest hardness and chewiness and largest diameter of type IIB muscle fibers compared to the other genotypes. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. [Ghrelin: beyond hunger regulation].

    Science.gov (United States)

    Milke García, Maria del Pilar

    2005-01-01

    Man ingests food to mitigate hunger (mediated by physiological and biochemical signals), satisfy appetite (subjective sensation) and because of psychosocial reasons. Satiation biomarkers (stop feeding) are gastric distention and hormones (CCK, GLP-1) and satiety biomarkers (induce feeding) are food-induced thermogenesis, body temperature, glycaemia and also hormones (insulin, leptin and ghrelin). Oxidative metabolism/body composition, tryptophan/serotonin and proinflammatory cytokines are also implicated on hunger physiology. At the present time, ghrelin is the only known circulating orexigenic with potential on hunger/body weight regulation. It is a neuropeptide (endogenous ligand for the GH secretagogue) recently isolated from the oxyntic mucosa and synthesized mainly in the stomach. Its blood concentration depends on diet, hyperglucemia and adiposity/leptin. It is secreted 1-2 hours preprandially and its concentration decreases drastically during the postprandium. Ghrelin acts on the lateral hypothalamus and theoretically inhibits proinflammatory cytokine secretion and antagonizes leptin. Ghrelin physiologically increases food intake and stimulates adipogenesis, gastrointestinal motility and gastric acid secretion, and has other hormonal and cardiovascular functions. Ghrelin blood concentration is reduced in massive obesity, non-alcoholic steatohepatitis, polycystic ovary syndrome, acromegaly, hypogonadism, ageing, short bowel syndrome and rheumatoid arthritis; and increased in primary or secondary anorexia, starvation, chronic liver disease and celiac disease. Cerebral and peritoneal ghrelin administration (rats) and systemic administration (rats and healthy volunteers, cancer patients or patients on peritoneal dialysis) promotes food consumption and increases adiposity, of utmost importance in the treatment of patients with anorexia.

  13. Divergent circuitry underlying food reward and intake effects of ghrelin: dopaminergic VTA-accumbens projection mediates ghrelin's effect on food reward but not food intake.

    Science.gov (United States)

    Skibicka, Karolina P; Shirazi, Rozita H; Rabasa-Papio, Cristina; Alvarez-Crespo, Mayte; Neuber, Corinna; Vogel, Heike; Dickson, Suzanne L

    2013-10-01

    Obesity has reached global epidemic proportions and creating an urgent need to understand mechanisms underlying excessive and uncontrolled food intake. Ghrelin, the only known circulating orexigenic hormone, potently increases food reward behavior. The neurochemical circuitry that links ghrelin to the mesolimbic reward system and to the increased food reward behavior remains unclear. Here we examine whether VTA-NAc dopaminergic signaling is required for the effects of ghrelin on food reward and intake. In addition, we examine the possibility of endogenous ghrelin acting on the VTA-NAc dopamine neurons. A D1-like or a D2 receptor antagonist was injected into the NAc in combination with ghrelin microinjection into the VTA to investigate whether this blockade attenuates ghrelin-induced food reward behavior. VTA injections of ghrelin produced a significant increase in food motivation/reward behavior, as measured by sucrose-induced progressive ratio operant conditioning, and chow intake. Pretreatment with either a D1-like or D2 receptor antagonist into the NAc, completely blocked the reward effect of ghrelin, leaving chow intake intact. We also found that this circuit is potentially relevant for the effects of endogenously released ghrelin as both antagonists reduced fasting (a state of high circulating levels of ghrelin) elevated sucrose-motivated behavior but not chow hyperphagia. Taken together our data identify the VTA to NAc dopaminergic projections, along with D1-like and D2 receptors in the NAc, as essential elements of the ghrelin responsive circuits controlling food reward behavior. Interestingly results also suggest that food reward behavior and simple intake of chow are controlled by divergent circuitry, where NAc dopamine plays an important role in food reward but not in food intake. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. FGF receptor genes and breast cancer susceptibility

    DEFF Research Database (Denmark)

    Agarwal, D; Pineda, S; Michailidou, K

    2014-01-01

    Background:Breast cancer is one of the most common malignancies in women. Genome-wide association studies have identified FGFR2 as a breast cancer susceptibility gene. Common variation in other fibroblast growth factor (FGF) receptors might also modify risk. We tested this hypothesis by studying...... genotyped single-nucleotide polymorphisms (SNPs) and imputed SNPs in FGFR1, FGFR3, FGFR4 and FGFRL1 in the Breast Cancer Association Consortium.Methods:Data were combined from 49 studies, including 53 835 cases and 50 156 controls, of which 89 050 (46 450 cases and 42 600 controls) were of European ancestry......, 12 893 (6269 cases and 6624 controls) of Asian and 2048 (1116 cases and 932 controls) of African ancestry. Associations with risk of breast cancer, overall and by disease sub-type, were assessed using unconditional logistic regression.Results:Little evidence of association with breast cancer risk...

  15. Direct versus indirect actions of ghrelin on hypothalamic NPY neurons.

    Science.gov (United States)

    Hashiguchi, Hiroshi; Sheng, Zhenyu; Routh, Vanessa; Gerzanich, Volodymyr; Simard, J Marc; Bryan, Joseph

    2017-01-01

    Assess direct versus indirect action(s) of ghrelin on hypothalamic NPY neurons. Electrophysiology was used to measure ion channel activity in NPY-GFP neurons in slice preparations. Ca2+ imaging was used to monitor ghrelin activation of isolated NPY GFP-labeled neurons. Immunohistochemistry was used to localize Trpm4, SUR1 and Kir6.2 in the hypothalamus. Acylated ghrelin depolarized the membrane potential (MP) of NPY-GFP neurons in brain slices. Depolarization resulted from a decreased input resistance (IR) in ~70% of neurons (15/22) or an increased IR in the remainder (7/22), consistent with the opening or closing of ion channels, respectively. Although tetrodotoxin (TTX) blockade of presynaptic action potentials reduced ghrelin-induced changes in MP and IR, ghrelin still significantly depolarized the MP and decreased IR in TTX-treated neurons, suggesting that ghrelin directly opens cation channel(s) in NPY neurons. In isolated NPY-GFP neurons, ghrelin produced a sustained rise of [Ca2+]c, with an EC50 ~110 pM. Pharmacologic studies confirmed that the direct action of ghrelin was through occupation of the growth hormone secretagogue receptor, GHS-R, and demonstrated the importance of the adenylate cyclase/cAMP/protein kinase A (PKA) and phospholipase C/inositol triphosphate (PLC/IP3) pathways as activators of 5' AMP-activated protein kinase (AMPK). Activation of isolated neurons was not affected by CNQX or TTX, but reducing [Na+]o suppressed activation, suggesting a role for Na+-permeable cation channels. SUR1 and two channel partners, Kir6.2 and Trpm4, were identified immunologically in NPY-GFP neurons in situ. The actions of SUR1 and Trpm4 modulators were informative: like ghrelin, diazoxide, a SUR1 agonist, elevated [Ca2+]c and glibenclamide, a SUR1 antagonist, partially suppressed ghrelin action, while 9-phenanthrol and flufenamic acid, selective Trpm4 antagonists, blocked ghrelin actions on isolated neurons. Ghrelin activation was unaffected by nifedipine and

  16. Functional group and stereochemical requirements for substrate binding by ghrelin O-acyltransferase revealed by unnatural amino acid incorporation.

    Science.gov (United States)

    Cleverdon, Elizabeth R; Davis, Tasha R; Hougland, James L

    2018-04-21

    Ghrelin is a small peptide hormone that undergoes a unique posttranslational modification, serine octanoylation, to play its physiological roles in processes including hunger signaling and glucose metabolism. Ghrelin O-acyltransferase (GOAT) catalyzes this posttranslational modification, which is essential for ghrelin to bind and activate its cognate GHS-R1a receptor. Inhibition of GOAT offers a potential avenue for modulating ghrelin signaling for therapeutic effect. Defining the molecular characteristics of ghrelin that lead to binding and recognition by GOAT will facilitate the development and optimization of GOAT inhibitors. We show that small peptide mimics of ghrelin substituted with 2,3-diaminopropanoic acid in place of the serine at the site of octanoylation act as submicromolar inhibitors of GOAT. Using these chemically modified analogs of desacyl ghrelin, we define key functional groups within the N-terminal sequence of ghrelin essential for binding to GOAT and determine GOAT's tolerance to backbone methylations and altered amino acid stereochemistry within ghrelin. Our study provides a structure-activity analysis of ghrelin binding to GOAT that expands upon activity-based investigations of ghrelin recognition and establishes a new class of potent substrate-mimetic GOAT inhibitors for further investigation and therapeutic interventions targeting ghrelin signaling. Copyright © 2018 Elsevier Inc. All rights reserved.

  17. Research progress of the bitter taste receptor genes in primates.

    Science.gov (United States)

    Feng, Ping; Luo, Rui-Jian

    2018-02-20

    Among the five basic tastes (umami, sweet, bitter, salty and sour), the perception of bitterness is believed to protect animals from digesting toxic and harmful substances, thus it is vital for animal survival. The taste of bitterness is triggered by the interaction between bitter substances and bitter taste receptors, which are encoded by Tas2rs. The gene numbers vary largely across species to meet different demands. So far, several ligands of bitter receptors have been identified in primates. They also discovered that the selective pressure of certain bitter taste receptor genes vary across taxa, genes or even different functional regions of the gene. In this review, we summarize the research progress of bitter taste receptor genes in primates by introducing the functional diversity of bitter receptors, the specific interaction between bitter taste receptors and ligands, the relationship between the evolutionary pattern of bitter taste receptors and diets, and the adaptive evolution of bitter taste receptor genes. We aim to provide a reference for further research on bitter receptor genes in primates.

  18. The essential role of endogenous ghrelin in growth hormone expression during zebrafish adenohypophysis development.

    Science.gov (United States)

    Li, Xi; He, Jiangyan; Hu, Wei; Yin, Zhan

    2009-06-01

    Ghrelin, a multifunctional hormone, including potent GH stimulation activity, has been suggested to be important during embryonic development. Expression of ghrelin has been confirmed in the zebrafish pancreas during embryonic stages. Interfering with ghrelin function using two specific antisense morpholino oligonucleotides causes defects during zebrafish embryonic development. In ghrelin morphants the expression of GH was abolished in zebrafish somatotropes, whereas the expression patterns of the other key molecules involved in hypothalamic-pituitary development and distinct pituitary hormones genes remain largely intact at the appropriate time during zebrafish adenohypophysis development. Effective rescue of the ghrelin morphants with exogenous ghrelin mRNA showed that the correct gene had been targeted. Moreover, by analyzing the efficiencies of the ghrelin morphants rescue experiments with various forms of exogenous mutant ghrelin mRNAs, we also demonstrated the essentiality of the form acyl-ghrelin on GH stimulation during zebrafish adenohypophysis development. Our in vivo experiments, for the first time, also provided evidence of the existence of functional obestatin in the C-terminal part of zebrafish proghrelin peptides. Our research here has demonstrated that zebrafish is a unique model for functional studies of endogenous ghrelin, especially during embryonic development.

  19. Polymorphism in leptin receptor gene was associated with obesity in ...

    African Journals Online (AJOL)

    The mutation in leptin receptor (LEPR) gene causes splicing abnormality that resulted in truncated receptor, aberrant signal transduction, leptin resistance, and obesity. This study aims to determine the association of LEPR gene polymorphisms, rs1137100 and rs1137101, on phenotype and leptin level between obese and ...

  20. Ghrelin and leptin interplay in prevention of testicular damage due to cryptochidism

    Science.gov (United States)

    Ghrelin, the endogenous ligand to the growth hormone secretagogue receptor (ghsr), is centrally implicated in body weight homeostasis. A novel murine model for ghrelin and its physiologic antagonist, leptin, was developed at this institution. Mice with a deletion of ghsr (ghsr -/-) or a targeted dis...

  1. Anti-ghrelin Spiegelmer inhibits exogenous ghrelin-induced increases in food intake, hoarding, and neural activation, but not food deprivation-induced increases

    Science.gov (United States)

    Teubner, Brett J. W.

    2013-01-01

    Circulating concentrations of the stomach-derived “hunger-peptide” ghrelin increase in direct proportion to the time since the last meal. Exogenous ghrelin also increases food intake in rodents and humans, suggesting ghrelin may increase post-fast ingestive behaviors. Food intake after food deprivation is increased by laboratory rats and mice, but not by humans (despite dogma to the contrary) or by Siberian hamsters; instead, humans and Siberian hamsters increase food hoarding, suggesting the latter as a model of fasting-induced changes in human ingestive behavior. Exogenous ghrelin markedly increases food hoarding by ad libitum-fed Siberian hamsters similarly to that after food deprivation, indicating sufficiency. Here, we tested the necessity of ghrelin to increase food foraging, food hoarding, and food intake, and neural activation [c-Fos immunoreactivity (c-Fos-ir)] using anti-ghrelin Spiegelmer NOX-B11–2 (SPM), an l-oligonucleotide that specifically binds active ghrelin, inhibiting peptide-receptor interaction. SPM blocked exogenous ghrelin-induced increases in food hoarding the first 2 days after injection, and foraging and food intake at 1–2 h and 2–4 h, respectively, and inhibited hypothalamic c-Fos-ir. SPM given every 24 h across 48-h food deprivation inconsistently inhibited food hoarding after refeeding and c-Fos-ir, similarly to inabilities to do so in laboratory rats and mice. These results suggest that ghrelin may not be necessary for food deprivation-induced foraging and hoarding and neural activation. A possible compensatory response, however, may underlie these findings because SPM treatment led to marked increases in circulating ghrelin concentrations. Collectively, these results show that SPM can block exogenous ghrelin-induced ingestive behaviors, but the necessity of ghrelin for food deprivation-induced ingestive behaviors remains unclear. PMID:23804279

  2. The Role of Ghrelin and Ghrelin Signaling in Aging.

    Science.gov (United States)

    Amitani, Marie; Amitani, Haruka; Cheng, Kai-Chun; Kairupan, Timothy Sean; Sameshima, Nanami; Shimoshikiryo, Ippei; Mizuma, Kimiko; Rokot, Natasya Trivena; Nerome, Yasuhito; Owaki, Tetsuhiro; Asakawa, Akihiro; Inui, Akio

    2017-07-12

    With our aging society, more people hope for a long and healthy life. In recent years, researchers have focused on healthy longevity factors. In particular, calorie restriction delays aging, reduces mortality, and extends life. Ghrelin, which is secreted during fasting, is well known as an orexigenic peptide. Because ghrelin is increased by caloric restriction, ghrelin may play an important role in the mechanism of longevity mediated by calorie restriction. In this review, we will discuss the role of orexigenic peptides with a particular focus on ghrelin. We conclude that the ghrelin-growth hormone secretagogue-R signaling pathway may play an important role in the anti-aging mechanism.

  3. Gastrointestinal Spatiotemporal mRNA Expression of Ghrelin vs Growth Hormone Receptor and New Growth Yield Machine Learning Model Based on Perturbation Theory.

    Science.gov (United States)

    Ran, Tao; Liu, Yong; Li, Hengzhi; Tang, Shaoxun; He, Zhixiong; Munteanu, Cristian R; González-Díaz, Humberto; Tan, Zhiliang; Zhou, Chuanshe

    2016-07-27

    The management of ruminant growth yield has economic importance. The current work presents a study of the spatiotemporal dynamic expression of Ghrelin and GHR at mRNA levels throughout the gastrointestinal tract (GIT) of kid goats under housing and grazing systems. The experiments show that the feeding system and age affected the expression of either Ghrelin or GHR with different mechanisms. Furthermore, the experimental data are used to build new Machine Learning models based on the Perturbation Theory, which can predict the effects of perturbations of Ghrelin and GHR mRNA expression on the growth yield. The models consider eight longitudinal GIT segments (rumen, abomasum, duodenum, jejunum, ileum, cecum, colon and rectum), seven time points (0, 7, 14, 28, 42, 56 and 70 d) and two feeding systems (Supplemental and Grazing feeding) as perturbations from the expected values of the growth yield. The best regression model was obtained using Random Forest, with the coefficient of determination R(2) of 0.781 for the test subset. The current results indicate that the non-linear regression model can accurately predict the growth yield and the key nodes during gastrointestinal development, which is helpful to optimize the feeding management strategies in ruminant production system.

  4. Ghrelin and eating disorders

    Directory of Open Access Journals (Sweden)

    Alessandra Donzelli Fabbri

    2015-04-01

    Full Text Available Background Ghrelin is a potent hormone with central and peripheral action. This hormone plays an important role in the regulation of appetite, food intake, and energy balance. Studies have suggested that ghrelin is involved with eating disorders (ED, particularly bingeing and purging. Genetic variants have also been studied to explain changes in eating behavior. Methods We conducted a literature review; we searched PubMed, Scientific Electronic Library Online (SciELO, and LILACS databases using the keywords “eating disorder”, “ghrelin”, “polymorphism”, “anorexia nervosa”, “bulimia nervosa”, “binge eating disorder”, and their combinations. We found 319 articles. Thirty-nine articles met the inclusion criteria. Results High levels of ghrelin were found in patients with anorexia nervosa (AN, especially in the purging subtype (AN-P. There was also a positive correlation between fasting ghrelin level and frequency of episodes of bingeing/purging in bulimia nervosa (BN and the frequency of bingeing in periodic binge eating disorder (BED. Some polymorphisms were associated with AN and BN. Conclusion Changes in ghrelin levels and its polymorphism may be involved in the pathogenesis of EDs; however, further studies should be conducted to clarify the associations.

  5. Ghrelin as a Survival Hormone.

    Science.gov (United States)

    Mani, Bharath K; Zigman, Jeffrey M

    2017-12-01

    Ghrelin administration induces food intake and body weight gain. Based on these actions, the ghrelin system was initially proposed as an antiobesity target. Subsequent studies using genetic mouse models have raised doubts about the role of the endogenous ghrelin system in mediating body weight homeostasis or obesity. However, this is not to say that the endogenous ghrelin system is not important metabolically or otherwise. Here we review an emerging concept in which the endogenous ghrelin system serves an essential function during extreme nutritional and psychological challenges to defend blood glucose, protect body weight, avoid exaggerated depression, and ultimately allow survival. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Gene Transfer and Molecular Cloning of the Human NGF Receptor

    Science.gov (United States)

    Chao, Moses V.; Bothwell, Mark A.; Ross, Alonzo H.; Koprowski, Hilary; Lanahan, Anthony A.; Buck, C. Randall; Sehgal, Amita

    1986-04-01

    Nerve growth factor (NGF) and its receptor are important in the development of cells derived from the neural crest. Mouse L cell transformants have been generated that stably express the human NGF receptor gene transfer with total human DNA. Affinity cross-linking, metabolic labeling and immunoprecipitation, and equilibrium binding with 125I-labeled NGF revealed that this NGF receptor had the same size and binding characteristics as the receptor from human melanoma cells and rat PC12 cells. The sequences encoding the NGF receptor were molecularly cloned using the human Alu repetitive sequence as a probe. A cosmid clone that contained the human NGF receptor gene allowed efficient transfection and expression of the receptor.

  7. Ghrelin O-acyltransferase (GOAT) is expressed in prostate cancer tissues and cell lines and expression is differentially regulated in vitro by ghrelin

    Science.gov (United States)

    2013-01-01

    Background Ghrelin is a 28 amino acid peptide hormone that is expressed in the stomach and a range of peripheral tissues, where it frequently acts as an autocrine/paracrine growth factor. Ghrelin is modified by a unique acylation required for it to activate its cognate receptor, the growth hormone secretagogue receptor (GHSR), which mediates many of the actions of ghrelin. Recently, the enzyme responsible for adding the fatty acid residue (octanoyl/acyl group) to the third amino acid of ghrelin, GOAT (ghrelin O-acyltransferase), was identified. Methods We used cell culture, quantitative real-time reverse transcription (RT)-PCR and immunohistochemistry to demonstrate the expression of GOAT in prostate cancer cell lines and tissues from patients. Real-time RT-PCR was used to demonstrate the expression of prohormone convertase (PC)1/3, PC2 and furin in prostate cancer cell lines. Prostate-derived cell lines were treated with ghrelin and desacyl ghrelin and the effect on GOAT expression was measured using quantitative RT-PCR. Results We have demonstrated that GOAT mRNA and protein are expressed in the normal prostate and human prostate cancer tissue samples. The RWPE-1 and RWPE-2 normal prostate-derived cell lines and the LNCaP, DU145, and PC3 prostate cancer cell lines express GOAT and at least one other enzyme that is necessary to produce mature, acylated ghrelin from proghrelin (PC1/3, PC2 or furin). Finally, ghrelin, but not desacyl ghrelin (unacylated ghrelin), can directly regulate the expression of GOAT in the RWPE-1 normal prostate derived cell line and the PC3 prostate cancer cell line. Ghrelin treatment (100nM) for 6 hours significantly decreased GOAT mRNA expression two-fold (P ghrelin did not regulate GOAT expression in the DU145 and LNCaP prostate cancer cell lines. Conclusions This study demonstrates that GOAT is expressed in prostate cancer specimens and cell lines. Ghrelin regulates GOAT expression, however, this is likely to be cell-type specific

  8. Ghrelin potentiates cardiac reactivity to stress by modulating sympathetic control and beta-adrenergic response.

    Science.gov (United States)

    Camargo-Silva, Gabriel; Turones, Larissa Córdova; da Cruz, Kellen Rosa; Gomes, Karina Pereira; Mendonça, Michelle Mendanha; Nunes, Allancer; de Jesus, Itamar Guedes; Colugnati, Diego Basile; Pansani, Aline Priscila; Pobbe, Roger Luis Henschel; Santos, Robson; Fontes, Marco Antônio Peliky; Guatimosim, Silvia; de Castro, Carlos Henrique; Ianzer, Danielle; Ferreira, Reginaldo Nassar; Xavier, Carlos Henrique

    2018-03-01

    Prior evidence indicates that ghrelin is involved in the integration of cardiovascular functions and behavioral responses. Ghrelin actions are mediated by the growth hormone secretagogue receptor subtype 1a (GHS-R1a), which is expressed in peripheral tissues and central areas involved in the control of cardiovascular responses to stress. In the present study, we assessed the role of ghrelin - GHS-R1a axis in the cardiovascular reactivity to acute emotional stress in rats. Ghrelin potentiated the tachycardia evoked by restraint and air jet stresses, which was reverted by GHS-R1a blockade. Evaluation of the autonomic balance revealed that the sympathetic branch modulates the ghrelin-evoked positive chronotropy. In isolated hearts, the perfusion with ghrelin potentiated the contractile responses caused by stimulation of the beta-adrenergic receptor, without altering the amplitude of the responses evoked by acetylcholine. Experiments in isolated cardiomyocytes revealed that ghrelin amplified the increases in calcium transient changes evoked by isoproterenol. Taken together, our results indicate that the Ghrelin-GHS-R1a axis potentiates the magnitude of stress-evoked tachycardia by modulating the autonomic nervous system and peripheral mechanisms, strongly relying on the activation of cardiac calcium transient and beta-adrenergic receptors. Copyright © 2018 Elsevier Inc. All rights reserved.

  9. Ghrelin and Eating Disorders

    Science.gov (United States)

    Atalayer, Deniz; Gibson, Charlisa; Konopacka, Alexandra; Geliebter, Allan

    2012-01-01

    There is growing evidence supporting a multifactorial etiology that includes genetic, neurochemical, and physiological components for eating disorders above and beyond the more conventional theories based on psychological and sociocultural factors. Ghrelin is one of the key gut signals associated with appetite, and the only known circulating hormone that triggers a positive energy balance by stimulating food intake. This review summarizes recent findings and several conflicting reports on ghrelin in eating disorders. Understanding these findings and inconsistencies may help in developing new methods to prevent and treat patients with these disorders. PMID:22960103

  10. Ghrelin attenuates vascular calcification in diabetic patients with amputation.

    Science.gov (United States)

    Xu, Suining; Ye, Fei; Li, Lihua; Yan, Jinchuan; Bao, Zhengyang; Sun, Zhen; Xu, Liangjie; Zhu, Jie; Wang, Zhongqun

    2017-07-01

    Vascular calcification is established to be a critical factor in diabetes mellitus, which causes cardiovascular and amputation complication of diabetic patients. OPG/RANKL/RANK axis serves as a regulatory role in vascular calcification. Ghrelin, an endogenous ligand of growth hormone secretagogue receptor (GHSR), has been reported to exhibit potent cardiovascular protective effects. However, the role of ghrelin in the regulation of diabetic vascular calcification is still elusive. Here, we reported the role of ghrelin and its relationship with OPG/RANKL/RANK system in patients with diabetic foot amputation. In vivo and in vitro investigations were performed. Sixty type 2 diabetic patients with foot amputation were enrolled in vivo investigation, and they were divided into three groups through Doppler ultrasound: mild stenosis group (n=20), moderate stenosis group (n=20), and severe stenosis/occlusion group (n=20). Morphological analysis results showed diffused calcium depositions in the anterior tibial artery of diabetic amputees. Compared with the mild and moderate stenosis group, the severe stenosis/occlusion group had more spotty calcium depositions in atherosclerotic plaques. Western blot analysis indicated the expressions of osteoprotegerin (OPG) and ghrelin were downregulated, while the expression of receptor activator of nuclear factor kappa B ligand (RANKL) was upregulated with the vascular stenosis aggravation. Pearson correlation analysis revealed a negative correlation between calcium content and ghrelin levels (r=-0.58, Pghrelin levels and sRANKL levels (r=-0.57, Pghrelin levels (r=0.63, PGhrelin blunted calcification in a dose-dependent manner. In addition, ghrelin upregulated OPG expression and downregulated RANKL expression in VSMC calcification when anti-OPG antibody and RANKL were performed. Collectively, we therefore conclude serum ghrelin level may be a predictor of diabetic vascular calcification. The possible mechanism may be related with OPG

  11. Impact of estrogen receptor α gene and oxytocin receptor gene polymorphisms on female sexuality

    Directory of Open Access Journals (Sweden)

    Anastasia K Armeni

    2017-02-01

    Full Text Available Over the past decades, research attention has increasingly been paid to the neurobiological component of sexual behavior. The aim of the present study was to investigate the correlation of estrogen receptor α (ERA gene polymorphism (rs2234693-PvuII (T→C substitution and oxytocin receptor gene polymorphism (rs53576 (G→A substitution with sexuality parameters of young, healthy women. One hundred thirty-three Greek heterosexual women, students in higher education institutions, 20–25 years of age, sexually active, with normal menstrual cycles (28–35 days, were recruited in the study. Exclusion criteria were chronic and/or major psychiatric diseases, use of oral contraceptive pills (OCs, polycystic ovary syndrome (PCOS, thyroid diseases as well as drugs that are implicated in hypothalamus–pituitary–gonadal axis. T allele (wildtype of rs2234693 (PvuII polymorphism of ERA gene was correlated with increased levels of arousal and lubrication, whereas A allele (polymorphic of rs53576 (OXTR polymorphism was correlated with increased arousal levels. The simultaneous presence of both T allele of rs2234693 (PvuII and A allele of rs53576 (OXTR polymorphisms (T + A group was correlated with increased arousal, orgasm levels as well as female sexual function index full score. To our knowledge, this is the first study to investigate the interaction between ERA and OXTR with regard to sexual function in women. Female sexuality is a complex behavioral trait that encompasses both biological and psychological components. It seems that variability in female sexual response stems from genetic variability that characterizes endocrine, neurotransmitter and central nervous system influences.

  12. A new variation in the promoter region, the -604 C>T, and the Leu72Met polymorphism of the ghrelin gene are associated with protection to insulin resistance.

    Science.gov (United States)

    Zavarella, S; Petrone, A; Zampetti, S; Gueorguiev, M; Spoletini, M; Mein, C A; Leto, G; Korbonits, M; Buzzetti, R

    2008-04-01

    Previous studies suggested that polymorphisms in the coding region of the preproghrelin were involved in the etiology of obesity and might modulate glucose-induced insulin secretion. We evaluated the association of a new variation, -604C>T, in the promoter region of the ghrelin gene, of Leu72Met (247C>A) and of Gln90Leu (265A>T), all haplotype-tagging single nucleotide polymorphisms (SNPs), with measures of insulin sensitivity in 1420 adult individuals. The three SNPs were genotyped using ABI PRISM 7900 HT Sequence Detection System. We used multiple linear regression analysis for quantitative traits and THESIAS software for haplotype analysis. We observed a protective effect exerted by Met72 variant of Leu72Met SNP on insulin resistance parameters; a significant decreasing trend from Leu/Leu to Leu/Met and to Met/Met homozygous subjects in triglycerides, fasting insulin levels and HOMA-IR index (P=0.02, 0.01 and 0.003, respectively), and, consistently, an increase in ghrelin levels (P=0.003) was found. A significant decrease from CC to TC and to TT genotypes in insulin levels and HOMA-IR index was also detected (P=0.00l for both), but only in subjects homozygous for Leu72, where the protective effect of Met72 was not present. The haplotype analysis results supported the data obtained by the evaluation of each single SNP, showing the highest value of insulin levels and HOMA-IR index in the -604(c)247(c) haplotype intermediate value in -604(T)247(C) and lowest value in -604(C)247(A). Our observations suggest a protective role of the Met72 variant and of -604 T allele in modulating insulin resistance. These SNPs or an unknown functional variant in linkage disequilibrium could increase ghrelin levels and probably insulin sensitivity.

  13. Contrasting association of a non-synonymous leptin receptor gene polymorphism with Wegener's granulomatosis and Churg-Strauss syndrome.

    Science.gov (United States)

    Wieczorek, Stefan; Holle, Julia U; Bremer, Jan P; Wibisono, David; Moosig, Frank; Fricke, Harald; Assmann, Gunter; Harper, Lorraine; Arning, Larissa; Gross, Wolfgang L; Epplen, Joerg T

    2010-05-01

    There is evidence that the leptin/ghrelin system is involved in T-cell regulation and plays a role in (auto)immune disorders such as SLE, RA and ANCA-associated vasculitides (AAVs). Here, we evaluate the genetic background of this system in WG. We screened variations in the genes encoding leptin, ghrelin and their receptors, the leptin receptor (LEPR) and the growth hormone secretagogue receptor (GHSR). Three single nucleotide polymorphisms (SNPs) in each gene region were analysed in 460 German WG cases and 878 ethnically matched healthy controls. A three-SNP haplotype of GHSR was significantly associated with WG [P = 0.0067; corrected P-value (P(c)) = 0.026; odds ratio (OR) = 1.30; 95% CI 1.08, 1.57], as was one non-synonymous SNP in LEPR (Lys656Asn, P = 0.0034; P(c) = 0.013; OR = 0.72; 95% CI 0.58, 0.90). These four SNPs were re-analysed in independent cohorts of 226 German WG cases and 519 controls. While the GHSR association was not confirmed, allele frequencies of the LEPR SNP were virtually identical to those from the initial cohorts. Analysis of this SNP in the combined WG and control panels revealed a significant association of the LEPR 656Lys allele with WG (P = 0.00032; P(c) = 0.0013; OR = 0.72; 95% CI 0.60, 0.86). Remarkably, the Lys656Asn SNP showed contrasting allele distribution in two cohorts of 108 and 88 German cases diagnosed with Churg-Strauss syndrome (CSS, combined P = 0.0067; OR = 1.41; 95% CI 1.10, 1.81), whereas identical allele frequencies were revealed when comparing British WG and microscopic polyangiitis cases. While GHSR has to be further evaluated, these data provide profound evidence for an association of the LEPR Lys656Asn SNP with AAV, resulting in opposing effects in WG and CSS.

  14. Peripherally Circulating Ghrelin Does Not Mediate Alcohol‐Induced Reward and Alcohol Intake in Rodents

    OpenAIRE

    Jerlhag, Elisabet; Ivanoff, Lisa; Vater, Axel; Engel, Jörgen A.

    2014-01-01

    Background Development of alcohol dependence, a chronic and relapsing disease, largely depends on the effects of alcohol on the brain reward systems. By elucidating the mechanisms involved in alcohol use disorder, novel treatment strategies may be developed. Ghrelin, the endogenous ligand for the growth hormone secretagogue receptor 1A, acts as an important regulator of energy balance. Recently ghrelin and its receptor were shown to mediate alcohol reward and to control alcohol consumption in...

  15. Fasting plasma total ghrelin concentrations in monozygotic twins discordant for obesity.

    Science.gov (United States)

    Leskelä, Piia; Ukkola, Olavi; Vartiainen, Johanna; Rönnemaa, Tapani; Kaprio, Jaakko; Bouchard, Claude; Kesäniemi, Y Antero

    2009-02-01

    Ghrelin is a hormone that is involved in the regulation of food intake. Neuronal, endocrine, and genetic factors have been shown to regulate plasma ghrelin levels; but the determinants of fasting ghrelin concentrations are not yet fully understood. The main aim was to explore the roles of adiposity and genetic differences in determining fasting plasma total ghrelin levels. We measured total ghrelin levels in a population of 23 monozygotic twin pairs discordant for obesity. In addition, 2 variants of ghrelin gene, namely, Arg51Gln and Leu72Met, were genotyped in 3 populations of monozygotic twin pairs: 23 obesity-discordant, 43 lean-concordant, and 46 obesity-concordant twin pairs. In discordant twins, lean co-twins had higher fasting plasma total ghrelin levels (950 pg/mL, SD = 328 pg/mL) than obese twins (720 pg/mL, SD = 143 pg/mL; P = .003). Arg51Gln-polymorphism of the ghrelin gene was equally distributed between the twin groups. However, there were significant differences in genotype frequencies at the Leu72Met polymorphism between the discordant and obese-concordant groups (P = .003) and between the discordant and lean-concordant groups (P = .011), but not between the 2 concordant groups. In the discordant group, there were fewer Met carriers (4%) than among the obese (17%) or the lean-concordant groups (15%). Plasma total ghrelin levels are affected by acquired obesity independent of genetic background. The Leu72 allele is particularly common among monozygotic twins discordant for obesity, suggesting that this ghrelin allele is more permissive in the regulation of energy balance. The ghrelin gene may thus play a role in the regulation of variability of body weight, such that Leu72 allele carriers are more prone to weight variability in response to environmental factors.

  16. The amygdala as a neurobiological target for ghrelin in rats: neuroanatomical, electrophysiological and behavioral evidence.

    Directory of Open Access Journals (Sweden)

    Mayte Alvarez-Crespo

    Full Text Available Here, we sought to demonstrate that the orexigenic circulating hormone, ghrelin, is able to exert neurobiological effects (including those linked to feeding control at the level of the amygdala, involving neuroanatomical, electrophysiological and behavioural studies. We found that ghrelin receptors (GHS-R are densely expressed in several subnuclei of the amygdala, notably in ventrolateral (LaVL and ventromedial (LaVM parts of the lateral amygdaloid nucleus. Using whole-cell patch clamp electrophysiology to record from cells in the lateral amygdaloid nucleus, we found that ghrelin reduced the frequency of mEPSCs recorded from large pyramidal-like neurons, an effect that could be blocked by co-application of a ghrelin receptor antagonist. In ad libitum fed rats, intra-amygdala administration of ghrelin produced a large orexigenic response that lasted throughout the 4 hr of testing. Conversely, in hungry, fasted rats ghrelin receptor blockade in the amygdala significantly reduced food intake. Finally, we investigated a possible interaction between ghrelin's effects on feeding control and emotional reactivity exerted at the level of the amygdala. In rats allowed to feed during a 1-hour period between ghrelin injection and anxiety testing (elevated plus maze and open field, intra-amygdala ghrelin had no effect on anxiety-like behavior. By contrast, if the rats were not given access to food during this 1-hour period, a decrease in anxiety-like behavior was observed in both tests. Collectively, these data indicate that the amygdala is a valid target brain area for ghrelin where its neurobiological effects are important for food intake and for the suppression of emotional (anxiety-like behaviors if food is not available.

  17. Characteristics of the mouse genomic histamine H1 receptor gene

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Isao; Taniuchi, Ichiro; Kitamura, Daisuke [Kyushu Univ., Fukuoka (Japan)] [and others

    1996-08-15

    We report here the molecular cloning of a mouse histamine H1 receptor gene. The protein deduced from the nucleotide sequence is composed of 488 amino acid residues with characteristic properties of GTP binding protein-coupled receptors. Our results suggest that the mouse histamine H1 receptor gene is a single locus, and no related sequences were detected. Interspecific backcross analysis indicated that the mouse histamine H1 receptor gene (Hrh1) is located in the central region of mouse Chromosome 6 linked to microphthalmia (Mitfmi), ras-related fibrosarcoma oncogene 1 (Raf1), and ret proto-oncogene (Ret) in a region of homology with human chromosome 3p. 12 refs., 3 figs.

  18. Immunohistochemical evidence for an endocrine/paracrine role for ghrelin in the reproductive tissues of sheep

    Directory of Open Access Journals (Sweden)

    Brown Yvonne A

    2005-10-01

    Full Text Available Abstract Background The gut hormone, ghrelin, is involved in the neuroendocrine and metabolic responses to hunger. In monogastric species, circulating ghrelin levels show clear meal-related and body weight-related changes. The pattern of secretion and its role in ruminant species is less clear. Ghrelin acts via growth hormone secretagogue receptors (GHSR-1a to alter food intake, fat utilization, and cellular proliferation. There is also evidence that ghrelin is involved in reproductive function. In the present study we used immunohistochemistry to investigate the presence of ghrelin and GHSR-1a in sheep reproductive tissues. In addition, we examined whether ghrelin and GHSR-1a protein expression is developmentally regulated in the adult and fetal ovine testis, and whether there is an association with markers of cellular proliferation, i.e. stem cell factor (SCF and proliferating cell nuclear antigen (PCNA. Methods Antibodies raised against ghrelin and its functional receptor, GHSR-type 1a, were used in standard immunohistochemical protocols on various reproductive tissues collected from adult and fetal sheep. GHSR-1a mRNA presence was also confirmed by in situ hybridisation. SCF and PCNA immunoexpression was investigated in fetal testicular samples. Adult and fetal testicular immunostaining for ghrelin, GHSR-1a, SCF and PCNA was analysed using computer-aided image analysis. Image analysis data were subjected to one-way ANOVA, with differences in immunostaining between time-points determined by Fisher's least significant difference. Results In adult sheep tissue, ghrelin and GHSR-1a immunostaining was detected in the stomach (abomasum, anterior pituitary gland, testis, ovary, and hypothalamic and hindbrain regions of the brain. In the adult testis, there was a significant effect of season (photoperiod on the level of immunostaining for ghrelin (p Conclusion Evidence is presented for the presence of ghrelin and its receptor in various reproductive

  19. Ghrelin and obestatin in thyroid gland - immunohistochemical expression in nodular goiter, papillary and medullary cancer.

    Science.gov (United States)

    Gurgul, Edyta; Kasprzak, Aldona; Blaszczyk, Agata; Biczysko, Maciej; Surdyk-Zasada, Joanna; Seraszek-Jaros, Agnieszka; Ruchala, Marek

    2015-01-01

    Previous studies analyzing ghrelin and obestatin expression in thyroid gland tissue are not unanimous and are mostly related to ghrelin. The role of ghrelin and obestatin in the thyroid gland appears very interesting due to their probable involvement in cell proliferation. Furthermore, since the thyroid gland is associated with the maintenance of energy balance, the relationship between ghrelin, obestatin and thyroid function is worthy of consideration. The aim of the study was to assess ghrelin and obestatin immunocytochemical expression in nodular goiter (NG), papillary cancer (PTC) and medullary cancer (MTC). Analyzed samples included 9 cases of NG, 8 cases of PTC and 11 cases of MTC. The analysis of ghrelin and obestatin expression was performed by use of the immunohistochemical (IHC) EnVision system and evaluated with filter HSV software (quantitative morphometric analysis). Quantitative ghrelin expression in MTC cells was higher than in NG (p = 0.013) and correlated negatively with the size of the tumor (r= -0.829, p thyroid cell proliferation. The differences between ghrelin and obestatin immunoreactivity in benign and malignant thyroid tumors could support the theory of alternative transcription of the preproghrelin gene and independent production of ghrelin and obestatin.

  20. Interleukin 18 receptor 1 gene polymorphisms are associated with asthma

    DEFF Research Database (Denmark)

    Zhu, Guohua; Whyte, Moira K B; Vestbo, Jørgen

    2008-01-01

    The interleukin 18 receptor (IL18R1) gene is a strong candidate gene for asthma. It has been implicated in the pathophysiology of asthma and maps to an asthma susceptibility locus on chromosome 2q12. The possibility of association between polymorphisms in IL18R1 and asthma was examined by genotyp...

  1. Vitamin D receptor gene variants in Parkinson's disease patients ...

    African Journals Online (AJOL)

    Background: Vitamin D plays an important role in neurodegenerative disorders as a crucial neuro-immunomodulator. Accumulating data provide evidences that vitamin D receptor (VDR) gene is a candidate gene for susceptibility to Parkinson's disease (PD). Aim: To find out whether the risk of the development of sporadic ...

  2. Hormonal control of spermatogenesis: expression of FSJH receptor and androgen receptor genes

    NARCIS (Netherlands)

    L.J. Blok (Leen)

    1992-01-01

    textabstractFSH and testosterone are the main hormonal regulators of spermatogenesis. The actions of androgens and FSH are mediated by their respective receptors. Receptor gene expression (mRNA and protein). is an important determinant of hormone action. Biochemical aspects of the regulation of

  3. Distribution and developmental changes of ghrelin-immunopositive cells in the pancreas of African ostrich chicks (Struthio camelus).

    Science.gov (United States)

    Wang, J X; Li, P; Zhang, X T; Ye, L X

    2017-09-01

    Ghrelin, the endogenous ligand for the growth hormone secretagogue receptor (GHS-R), is produced by multiple cell types and affects feeding behavior, metabolic regulation, and energy balance. In the mammalian pancreas, the types of endocrine cells that are immunoreactive to ghrelin vary. However, little was known about its distribution and developmental changes in the pancreas of African ostrich chicks (Struthio camelus). In the present study, the distribution, morphological characteristics, and developmental changes of ghrelin-immunopositive (ghrelin-ip) cells in the pancreas of African ostrich chicks were investigated using immunohistochemistry. Ghrelin-ip cells were found in both the pancreatic islets and acinar cell regions. The greatest number of ghrelin-ip cells were found in the pancreatic islets, and were primarily observed at the periphery of the islets; some ghrelin-ip cells were also located in the central portion of the pancreatic islets. Interestingly, from postnatal d 1 to d 90, there was a steady decrease in the number of ghrelin-ip cells in the pancreatic islets and acinar cell regions. These results clearly demonstrated that ghrelin-ip cells exist and decreased with age in the African ostrich pancreas from postnatal d 1 to d90. Thus, these findings indicated that ghrelin may be involved in the development of the pancreas in the African ostrich. © 2017 Poultry Science Association Inc.

  4. Dopamine receptor gene expression by enkephalin neurons in rat forebrain

    International Nuclear Information System (INIS)

    Le Moine, C.; Normand, E.; Guitteny, A.F.; Fouque, B.; Teoule, R.; Bloch, B.

    1990-01-01

    In situ hybridization experiments were performed with brain sections from normal, control and haloperidol-treated rats to identify and map the cells expressing the D2 dopamine receptor gene. D2 receptor mRNA was detected with radioactive or biotinylated oligonucleotide probes. D2 receptor mRNA was present in glandular cells of the pituitary intermediate lobe and in neurons of the substantia nigra, ventral tegmental area, and forebrain, especially in caudate putamen, nucleus accumbens, olfactory tubercle, and piriform cortex. Hybridization with D2 and preproenkephalin A probes in adjacent sections, as well as combined hybridization with the two probes in the same sections, demonstrated that all detectable enkephalin neurons in the striatum contained the D2 receptor mRNA. Large neurons in caudate putamen, which were unlabeled with the preproenkephalin A probe and which may have been cholinergic, also expressed the D2 receptor gene. Haloperidol treatment (14 or 21 days) provoked an increase in mRNA content for D2 receptor and preproenkephalin A in the striatum. This suggests that the increase in D2 receptor number observed after haloperidol treatment is due to increased activity of the D2 gene. These results indicate that in the striatum, the enkephalin neurons are direct targets for dopamine liberated from mesostriatal neurons

  5. Dopamine receptor gene expression by enkephalin neurons in rat forebrain

    Energy Technology Data Exchange (ETDEWEB)

    Le Moine, C.; Normand, E.; Guitteny, A.F.; Fouque, B.; Teoule, R.; Bloch, B. (Universite de Bordeaux II (France))

    1990-01-01

    In situ hybridization experiments were performed with brain sections from normal, control and haloperidol-treated rats to identify and map the cells expressing the D2 dopamine receptor gene. D2 receptor mRNA was detected with radioactive or biotinylated oligonucleotide probes. D2 receptor mRNA was present in glandular cells of the pituitary intermediate lobe and in neurons of the substantia nigra, ventral tegmental area, and forebrain, especially in caudate putamen, nucleus accumbens, olfactory tubercle, and piriform cortex. Hybridization with D2 and preproenkephalin A probes in adjacent sections, as well as combined hybridization with the two probes in the same sections, demonstrated that all detectable enkephalin neurons in the striatum contained the D2 receptor mRNA. Large neurons in caudate putamen, which were unlabeled with the preproenkephalin A probe and which may have been cholinergic, also expressed the D2 receptor gene. Haloperidol treatment (14 or 21 days) provoked an increase in mRNA content for D2 receptor and preproenkephalin A in the striatum. This suggests that the increase in D2 receptor number observed after haloperidol treatment is due to increased activity of the D2 gene. These results indicate that in the striatum, the enkephalin neurons are direct targets for dopamine liberated from mesostriatal neurons.

  6. Acylated and unacylated ghrelin do not directly stimulate glucose transport in isolated rodent skeletal muscle.

    Science.gov (United States)

    Cervone, Daniel T; Dyck, David J

    2017-07-01

    Emerging evidence implicates ghrelin, a gut-derived, orexigenic hormone, as a potential mediator of insulin-responsive peripheral tissue metabolism. However, in vitro and in vivo studies assessing ghrelin's direct influence on metabolism have been controversial, particularly due to confounding factors such as the secondary rise in growth hormone (GH) after ghrelin injection. Skeletal muscle is important in the insulin-stimulated clearance of glucose, and ghrelin's exponential rise prior to a meal could potentially facilitate this. This study was aimed at elucidating any direct stimulatory action that ghrelin may have on glucose transport and insulin signaling in isolated rat skeletal muscle, in the absence of confounding secondary factors. Oxidative soleus and glycolytic extensor digitorum longus skeletal muscles were isolated from male Sprague Dawley rats in the fed state and incubated with various concentrations of acylated and unacylated ghrelin in the presence or absence of insulin. Ghrelin did not stimulate glucose transport in either muscle type, with or without insulin. Moreover, GH had no acute, direct stimulatory effect on either basal or insulin-stimulated muscle glucose transport. In agreement with the lack of observed effect on glucose transport, ghrelin and GH also had no stimulatory effect on Ser 473 AKT or Thr 172 AMPK phosphorylation, two key signaling proteins involved in glucose transport. Furthermore, to our knowledge, we are among the first to show that ghrelin can act independent of its receptor and cause an increase in calmodulin-dependent protein kinase 2 (CaMKII) phosphorylation in glycolytic muscle, although this was not associated with an increase in glucose transport. We conclude that both acylated and unacylated ghrelin have no direct, acute influence on skeletal muscle glucose transport. Furthermore, the immediate rise in GH in response to ghrelin also does not appear to directly stimulate glucose transport in muscle. © 2017 The

  7. The Mouse Solitary Odorant Receptor Gene Promoters as Models for the Study of Odorant Receptor Gene Choice.

    Directory of Open Access Journals (Sweden)

    Andrea Degl'Innocenti

    Full Text Available In vertebrates, several anatomical regions located within the nasal cavity mediate olfaction. Among these, the main olfactory epithelium detects most conventional odorants. Olfactory sensory neurons, provided with cilia exposed to the air, detect volatile chemicals via an extremely large family of seven-transmembrane chemoreceptors named odorant receptors. Their genes are expressed in a monogenic and monoallelic fashion: a single allele of a single odorant receptor gene is transcribed in a given mature neuron, through a still uncharacterized molecular mechanism known as odorant receptor gene choice.Odorant receptor genes are typically arranged in genomic clusters, but a few are isolated (we call them solitary from the others within a region broader than 1 Mb upstream and downstream with respect to their transcript's coordinates. The study of clustered genes is problematic, because of redundancy and ambiguities in their regulatory elements: we propose to use the solitary genes as simplified models to understand odorant receptor gene choice.Here we define number and identity of the solitary genes in the mouse genome (C57BL/6J, and assess the conservation of the solitary status in some mammalian orthologs. Furthermore, we locate their putative promoters, predict their homeodomain binding sites (commonly present in the promoters of odorant receptor genes and compare candidate promoter sequences with those of wild-caught mice. We also provide expression data from histological sections.In the mouse genome there are eight intact solitary genes: Olfr19 (M12, Olfr49, Olfr266, Olfr267, Olfr370, Olfr371, Olfr466, Olfr1402; five are conserved as solitary in rat. These genes are all expressed in the main olfactory epithelium of three-day-old mice. The C57BL/6J candidate promoter of Olfr370 has considerably varied compared to its wild-type counterpart. Within the putative promoter for Olfr266 a homeodomain binding site is predicted. As a whole, our findings

  8. The effect of ghrelin upon the early immune response in lean and obese mice during sepsis.

    Directory of Open Access Journals (Sweden)

    Daniel Siegl

    Full Text Available It is well established that obesity-related hormones can have modulatory effects associated with the immune response. Ghrelin, a hormone mainly derived from endocrine cells of the gastric mucosa, regulates appetite, energy expenditure and body weight counteracting leptin, a hormone mainly derived from adipocytes. Additionally, receptors of both have been detected on immune cells and demonstrated an immune regulatory function during sepsis.In the present study, the effect of peripheral ghrelin administration on early immune response and survival was investigated with lean mice and mice with diet-induced obesity using cecal ligation and puncture to induce sepsis.In the obese group, we found that ghrelin treatment improved survival, ameliorated hypothermia, and increased hyperleptinemia as compared to the lean controls. We also observed that ghrelin treatment divergently regulated serum IL-1ß and TNF-α concentrations in both lean and obese septic mice. Ghrelin treatment initially decreased but later resulted in increased bacteriaemia in lean mice while having no impact upon obese mice. Similarly, ghrelin treatment increased early neutrophil oxidative burst while causing a decrease 48 hours after sepsis inducement.In conclusion, as the immune response to sepsis temporally changes, ghrelin treatment differentially mediates this response. Specifically, we observed that ghrelin conferred protective effects during the early phase of sepsis, but during the later phase deteriorated immune response and outcome. These adverse effects were more pronounced upon lean mice as compared to obese mice.

  9. Exogenous ghrelin regulates proliferation and apoptosis in the hypotrophic gut mucosa of the rat.

    Science.gov (United States)

    de Segura, Ignacio A Gómez; Vallejo-Cremades, María Teresa; Lomas, Jesús; Sánchez, Miriam F; Caballero, María Isabel; Largo, Carlota; De Miguel, Enrique

    2010-04-01

    Ghrelin is the natural endogenous ligand for growth hormone secretagogue receptors. This peptide regulates energy homeostasis and expenditure and is a potential link between gut absorptive function and growth. We hypothesized that ghrelin may induce a proliferative and antiapoptotic action promoting the recovery of the hypotrophic gut mucosa. Therefore, the aim of the study was to determine the action of exogenous ghrelin following gut mucosal hypotrophia in rats fed an elemental diet. An elemental diet provides readily absorbable simple nutrients and is usually given to patients with absorptive dysfunction. Male Wistar rats (n = 48) were fed the elemental diet for one week to induce mucosal hypotrophy and then treated for another week with systemic ghrelin and pair-fed with either a normoproteic or hyperproteic isocaloric liquid diet. Another group received a standard diet instead of the elemental diet and served as control (normotrophy). The elemental diet induced intestinal hypotrophia characterized by decreased proliferation in the ileum and increased apoptosis in jejunum and ileum. Ghrelin administration restored normal levels of proliferation in the ileum and apoptosis in the jejunum, with partial apoptosis restoration in the ileum. Ghrelin levels in plasma and fundus were increased in all groups, although the highest levels were found in rats treated with exogenous ghrelin. Ghrelin administration has a positive effect in the hypotrophic gut, regulating both proliferation and apoptosis towards a physiological balance counteracting the negative changes induced by an elemental diet in the intestines.

  10. Fasting levels of ghrelin covary with the brain response to food pictures.

    Science.gov (United States)

    Kroemer, Nils B; Krebs, Lena; Kobiella, Andrea; Grimm, Oliver; Pilhatsch, Maximilian; Bidlingmaier, Martin; Zimmermann, Ulrich S; Smolka, Michael N

    2013-09-01

    Ghrelin figures prominently in the regulation of appetite in normal-weighed individuals. The apparent failure of this mechanism in eating disorders and the connection to addictive behavior in general demand a deeper understanding of the endogenous central-nervous processes related to ghrelin. Thus, we investigated processing of pictures showing palatable food after overnight fasting and following a standardized caloric intake (i.e. a 75-g oral glucose tolerance test) using functional magnetic resonance imaging and correlated it with blood plasma levels of ghrelin. Twenty-six healthy female and male volunteers viewed food and control pictures in a block design and rated their appetite after each block. Fasting levels of ghrelin correlated positively with food-cue reactivity in a bilateral network of visual processing-, reward- and taste-related regions, including limbic and paralimbic regions. Notably, among those regions were the hypothalamus and the midbrain where ghrelin receptors are densely concentrated. In addition, high fasting ghrelin levels were associated with stronger increases of subjective appetite during the food-cue-reactivity task. In conclusion, brain activation and subjective appetite ratings suggest that ghrelin elevates the hedonic effects of food pictures. Thereby, fasting ghrelin levels may generally enhance subjective craving when confronted with reward cues. © 2012 The Authors, Addiction Biology © 2012 Society for the Study of Addiction.

  11. Arcuate AgRP neurons mediate orexigenic and glucoregulatory actions of ghrelin.

    Science.gov (United States)

    Wang, Qian; Liu, Chen; Uchida, Aki; Chuang, Jen-Chieh; Walker, Angela; Liu, Tiemin; Osborne-Lawrence, Sherri; Mason, Brittany L; Mosher, Christina; Berglund, Eric D; Elmquist, Joel K; Zigman, Jeffrey M

    2014-02-01

    The hormone ghrelin stimulates eating and helps maintain blood glucose upon caloric restriction. While previous studies have demonstrated that hypothalamic arcuate AgRP neurons are targets of ghrelin, the overall relevance of ghrelin signaling within intact AgRP neurons is unclear. Here, we tested the functional significance of ghrelin action on AgRP neurons using a new, tamoxifen-inducible AgRP-CreER(T2) transgenic mouse model that allows spatiotemporally-controlled re-expression of physiological levels of ghrelin receptors (GHSRs) specifically in AgRP neurons of adult GHSR-null mice that otherwise lack GHSR expression. AgRP neuron-selective GHSR re-expression partially restored the orexigenic response to administered ghrelin and fully restored the lowered blood glucose levels observed upon caloric restriction. The normalizing glucoregulatory effect of AgRP neuron-selective GHSR expression was linked to glucagon rises and hepatic gluconeogenesis induction. Thus, our data indicate that GHSR-containing AgRP neurons are not solely responsible for ghrelin's orexigenic effects but are sufficient to mediate ghrelin's effects on glycemia.

  12. Ghrelin ameliorates intestinal barrier dysfunction in experimental colitis by inhibiting the activation of nuclear factor-kappa B

    International Nuclear Information System (INIS)

    Cheng, Jian; Zhang, Lin; Dai, Weiqi; Mao, Yuqing; Li, Sainan; Wang, Jingjie; Li, Huanqing; Guo, Chuanyong; Fan, Xiaoming

    2015-01-01

    Aim: This study aimed to investigate the effect and underlying mechanism of ghrelin on intestinal barrier dysfunction in dextran sulfate sodium (DSS)-induced colitis. Methods and results: Acute colitis was induced in C57BL/6J mice by administering 2.5% DSS. Saline or 25, 125, 250 μg/kg ghrelin was administrated intraperitoneally (IP) to mice 1 day before colitis induction and on days 4, 5, and 6 after DSS administration. IP injection of a ghrelin receptor antagonist, [D-lys 3 ]-GHRP-6, was performed immediately prior to ghrelin injection. Ghrelin (125 or 250 μg/kg) could reduce the disease activity index, histological score, and myeloperoxidase activities in experimental colitis, and also prevented shortening of the colon. Ghrelin could prevent the reduction of transepithelial electrical resistance and tight junction expression, and bolstered tight junction structural integrity and regulated cytokine secretion. Ultimately, ghrelin inhibited nuclear factor kappa B (NF-κB), inhibitory κB-α, myosin light chain kinase, and phosphorylated myosin light chain 2 activation. Conclusions: Ghrelin prevented the breakdown of intestinal barrier function in DSS-induced colitis. The protective effects of ghrelin on intestinal barrier function were mediated by its receptor GHSR-1a. The inhibition of NF-κB activation might be part of the mechanism underlying the effects of ghrelin that protect against barrier dysfunction. - Highlights: • Ghrelin ameliorates intestinal barrier dysfunction in experimental colitis. • The effect of ghrelin is mediated by GHSR-1a. • Inhibition of NF-κB activation

  13. Ghrelin ameliorates intestinal barrier dysfunction in experimental colitis by inhibiting the activation of nuclear factor-kappa B

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Jian; Zhang, Lin [Department of Gastroenterology, Jinshan Hospital of Fudan University, Shanghai (China); Dai, Weiqi [Department of Gastroenterology, Shanghai Tenth People' s Hospital, Tongji University, Shanghai (China); Mao, Yuqing [Department of Gastroenterology, Jinshan Hospital of Fudan University, Shanghai (China); Li, Sainan [Department of Gastroenterology, Shanghai Tenth People' s Hospital, Tongji University, Shanghai (China); Wang, Jingjie; Li, Huanqing [Department of Gastroenterology, Jinshan Hospital of Fudan University, Shanghai (China); Guo, Chuanyong [Department of Gastroenterology, Shanghai Tenth People' s Hospital, Tongji University, Shanghai (China); Fan, Xiaoming, E-mail: xiaomingfan57@sina.com [Department of Gastroenterology, Jinshan Hospital of Fudan University, Shanghai (China)

    2015-02-27

    Aim: This study aimed to investigate the effect and underlying mechanism of ghrelin on intestinal barrier dysfunction in dextran sulfate sodium (DSS)-induced colitis. Methods and results: Acute colitis was induced in C57BL/6J mice by administering 2.5% DSS. Saline or 25, 125, 250 μg/kg ghrelin was administrated intraperitoneally (IP) to mice 1 day before colitis induction and on days 4, 5, and 6 after DSS administration. IP injection of a ghrelin receptor antagonist, [D-lys{sup 3}]-GHRP-6, was performed immediately prior to ghrelin injection. Ghrelin (125 or 250 μg/kg) could reduce the disease activity index, histological score, and myeloperoxidase activities in experimental colitis, and also prevented shortening of the colon. Ghrelin could prevent the reduction of transepithelial electrical resistance and tight junction expression, and bolstered tight junction structural integrity and regulated cytokine secretion. Ultimately, ghrelin inhibited nuclear factor kappa B (NF-κB), inhibitory κB-α, myosin light chain kinase, and phosphorylated myosin light chain 2 activation. Conclusions: Ghrelin prevented the breakdown of intestinal barrier function in DSS-induced colitis. The protective effects of ghrelin on intestinal barrier function were mediated by its receptor GHSR-1a. The inhibition of NF-κB activation might be part of the mechanism underlying the effects of ghrelin that protect against barrier dysfunction. - Highlights: • Ghrelin ameliorates intestinal barrier dysfunction in experimental colitis. • The effect of ghrelin is mediated by GHSR-1a. • Inhibition of NF-κB activation.

  14. Integrated olfactory receptor and microarray gene expression databases

    Directory of Open Access Journals (Sweden)

    Crasto Chiquito J

    2007-06-01

    Full Text Available Abstract Background Gene expression patterns of olfactory receptors (ORs are an important component of the signal encoding mechanism in the olfactory system since they determine the interactions between odorant ligands and sensory neurons. We have developed the Olfactory Receptor Microarray Database (ORMD to house OR gene expression data. ORMD is integrated with the Olfactory Receptor Database (ORDB, which is a key repository of OR gene information. Both databases aim to aid experimental research related to olfaction. Description ORMD is a Web-accessible database that provides a secure data repository for OR microarray experiments. It contains both publicly available and private data; accessing the latter requires authenticated login. The ORMD is designed to allow users to not only deposit gene expression data but also manage their projects/experiments. For example, contributors can choose whether to make their datasets public. For each experiment, users can download the raw data files and view and export the gene expression data. For each OR gene being probed in a microarray experiment, a hyperlink to that gene in ORDB provides access to genomic and proteomic information related to the corresponding olfactory receptor. Individual ORs archived in ORDB are also linked to ORMD, allowing users access to the related microarray gene expression data. Conclusion ORMD serves as a data repository and project management system. It facilitates the study of microarray experiments of gene expression in the olfactory system. In conjunction with ORDB, ORMD integrates gene expression data with the genomic and functional data of ORs, and is thus a useful resource for both olfactory researchers and the public.

  15. Ghrelin reverses experimental diabetic neuropathy in mice

    Energy Technology Data Exchange (ETDEWEB)

    Kyoraku, Itaru; Shiomi, Kazutaka [Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Kiyotake, Miyazaki 889-1692 (Japan); Kangawa, Kenji [Department of Biochemistry, National Cardiovascular Center Research Institute, Osaka 565-8565 (Japan); Nakazato, Masamitsu, E-mail: nakazato@med.miyazaki-u.ac.jp [Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Kiyotake, Miyazaki 889-1692 (Japan)

    2009-11-20

    Ghrelin, an acylated peptide produced in the stomach, increases food intake and growth hormone secretion, suppresses inflammation and oxidative stress, and promotes cell survival and proliferation. We investigated the pharmacological potential of ghrelin in the treatment of polyneuropathy in uncontrolled streptozotocin (STZ)-induced diabetes in mice. Ghrelin or desacyl-ghrelin was administered daily for 4 weeks after STZ-induced diabetic polyneuropathy had developed. Ghrelin administration did not alter food intake, body weight gain, blood glucose levels, or plasma insulin levels when compared with mice given saline or desacyl-ghrelin administration. Ghrelin administration ameliorated reductions in motor and sensory nerve conduction velocities in diabetic mice and normalized their temperature sensation and plasma concentrations of 8-isoprostaglandin {alpha}, an oxidative stress marker. Desacyl-ghrelin failed to have any effect. Ghrelin administration in a mouse model of diabetes ameliorated polyneuropathy. Thus, ghrelin's effects represent a novel therapeutic paradigm for the treatment of this otherwise intractable disorder.

  16. Ghrelin reverses experimental diabetic neuropathy in mice

    International Nuclear Information System (INIS)

    Kyoraku, Itaru; Shiomi, Kazutaka; Kangawa, Kenji; Nakazato, Masamitsu

    2009-01-01

    Ghrelin, an acylated peptide produced in the stomach, increases food intake and growth hormone secretion, suppresses inflammation and oxidative stress, and promotes cell survival and proliferation. We investigated the pharmacological potential of ghrelin in the treatment of polyneuropathy in uncontrolled streptozotocin (STZ)-induced diabetes in mice. Ghrelin or desacyl-ghrelin was administered daily for 4 weeks after STZ-induced diabetic polyneuropathy had developed. Ghrelin administration did not alter food intake, body weight gain, blood glucose levels, or plasma insulin levels when compared with mice given saline or desacyl-ghrelin administration. Ghrelin administration ameliorated reductions in motor and sensory nerve conduction velocities in diabetic mice and normalized their temperature sensation and plasma concentrations of 8-isoprostaglandin α, an oxidative stress marker. Desacyl-ghrelin failed to have any effect. Ghrelin administration in a mouse model of diabetes ameliorated polyneuropathy. Thus, ghrelin's effects represent a novel therapeutic paradigm for the treatment of this otherwise intractable disorder.

  17. The Neurobiological Impact of Ghrelin Suppression after Oesophagectomy

    Directory of Open Access Journals (Sweden)

    Conor F. Murphy

    2016-12-01

    Full Text Available Ghrelin, discovered in 1999, is a 28-amino-acid hormone, best recognized as a stimulator of growth hormone secretion, but with pleiotropic functions in the area of energy homeostasis, such as appetite stimulation and energy expenditure regulation. As the intrinsic ligand of the growth hormone secretagogue receptor (GHS-R, ghrelin appears to have a broad array of effects, but its primary role is still an area of debate. Produced mainly from oxyntic glands in the stomach, but with a multitude of extra-metabolic roles, ghrelin is implicated in complex neurobiological processes. Comprehensive studies within the areas of obesity and metabolic surgery have clarified the mechanism of these operations. As a stimulator of growth hormone (GH, and an apparent inducer of positive energy balance, other areas of interest include its impact on carcinogenesis and tumour proliferation and its role in the cancer cachexia syndrome. This has led several authors to study the hormone in the cancer setting. Ghrelin levels are acutely reduced following an oesophagectomy, a primary treatment modality for oesophageal cancer. We sought to investigate the nature of this postoperative ghrelin suppression, and its neurobiological implications.

  18. Molecular cloning, characterization, and expression analysis of ghrelin and cholecystokinin in the pigeon (Columba livia).

    Science.gov (United States)

    Xie, P; Wan, X P; Bu, Z; Zou, X T

    2016-11-01

    Ghrelin and cholecystokinin (CCK) are multifunctional peptides. In the current study, complete sequences of ghrelin (800 bp) and CCK (739 bp) were firstly cloned in Columba livia by using rapid amplification of cDNA ends (RACE) method. The open reading frames of ghrelin (351bp) and CCK (393bp) encoded 116 amino acids and 130 amino acids, respectively. Sequence comparison indicated that pigeon ghrelin and CCK shared high identity with those reported in other avian species. Quantitative real-time PCR analysis found that ghrelin and CCK mRNAs expressed in three intestinal segments of pigeon during development. Both ghrelin and CCK showed generally higher expressions at days posthatch than embryonic periods regardless of intestinal segments. In duodenum and ileum, the expressions of ghrelin and CCK mRNA reached the peak values at 8 d posthatch. Jejunum CCK mRNA level increased linearly after hatching, and reached the highest point at posthatch 28 d. Based on documented effects of long chain fatty acids (LCFAs) on pigeon ghrelin and CCK expression were also investigated in vitro. Higher concentrations (50 μM or 250 μM) of linoleic acid, α-linolenic acid or arachidonic acid can significantly increase ghrelin mRNA level in pigeon jejunum. However, for oleic acid, the induction of ghrelin gene expressions needed a lower concentration (5 μM). 5 μM of linoleic acid, α-linolenic acid or arachidonic acid and 250 μM palmitic acid repressed CCK expression significantly. A higher concentration (250 μM) of oleic acid or α-linolenic acid can up-regulate CCK mRNA level significantly. Our results indicated that ghrelin and CCK may act key functions in pigeon intestine development and their expressions could be regulated by LCFAs. © 2016 Poultry Science Association Inc.

  19. Production of ghrelin by the stomach of patients with gastric cancer.

    Science.gov (United States)

    Kizaki, Junya; Aoyagi, Keishiro; Sato, Takahiro; Kojima, Masayasu; Shirouzu, Kazuo

    2014-01-01

    Poor nutrition and weight loss are important factors contributing to poor quality of life (QOL) after gastrectomy in patients with gastric cancer. Ghrelin is a hormone produced by the stomach that, plays a role in appetite increase and fat storage. The present study aims to clarify the location of ghrelin mRNA in the stomach, changes in blood ghrelin concentrations after gastrectomy and whether or not they are associated with the reconstruction method in patients with gastric cancer. We collected seven normal mucosa samples from different parts of six totally resected stomachs with gastric cancer. We extracted RNA from the normal mucosa, synthesized cDNA from total RNA (1 μg), and then quantified ghrelin mRNA using quantitative real-time polymerase chain reaction (Q-PCR). Ghrelin blood concentrations were measured using enzyme-linked immunosorbent assay (ELISA) kits in 74 patients with gastric cancer (total gastrectomy (TG), n=23; distal gastrectomy (DG), n=30; proximal gastrectomy (PG), n=11; pylorus preserving gastrectomy (PPG), n=10). In order, the ghrelin gene was expressed most frequently in the gastric body, followed by the fornix, cardia, antrum and pylorus ring. Blood ghrelin concentrations after surgery similarly changed in all groups. The average blood ghrelin concentrations were significantly higher in the DG and PPG groups than in the TG group on postoperative days (POD) 1, 7, 30, 90 and 180. However, blood ghrelin concentrations did not significantly differ between the DG and TG groups on POD 270 and 360. Cells that produce ghrelin are supposed to be located mostly in the fundic gland of the stomach. We speculate that the production of ghrelin from other organs increases from around nine months after total gastrectomy. Therefore, evaluating the nutritional status and the weight of patients at nine months after total gastrectomy is important to help these patients improve their QOL.

  20. Concomitant release of ventral tegmental acetylcholine and accumbal dopamine by ghrelin in rats.

    Directory of Open Access Journals (Sweden)

    Elisabet Jerlhag

    Full Text Available Ghrelin, an orexigenic peptide, regulates energy balance specifically via hypothalamic circuits. Growing evidence suggest that ghrelin increases the incentive value of motivated behaviours via activation of the cholinergic-dopaminergic reward link. It encompasses the cholinergic afferent projection from the laterodorsal tegmental area (LDTg to the dopaminergic cells of the ventral tegmental area (VTA and the mesolimbic dopamine system projecting from the VTA to nucleus accumbens (N.Acc.. Ghrelin receptors (GHS-R1A are expressed in these reward nodes and ghrelin administration into the LDTg increases accumbal dopamine, an effect involving nicotinic acetylcholine receptors in the VTA. The present series of experiments were undertaken directly to test this hypothesis. Here we show that ghrelin, administered peripherally or locally into the LDTg concomitantly increases ventral tegmental acetylcholine as well as accumbal dopamine release. A GHS-R1A antagonist blocks this synchronous neurotransmitter release induced by peripheral ghrelin. In addition, local perfusion of the unselective nicotinic antagonist mecamylamine into the VTA blocks the ability of ghrelin (administered into the LDTg to increase N.Acc.-dopamine, but not VTA-acetylcholine. Collectively our data indicate that ghrelin activates the LDTg causing a release of acetylcholine in the VTA, which in turn activates local nicotinic acetylcholine receptors causing a release of accumbal dopamine. Given that a dysfunction in the cholinergic-dopaminergic reward system is involved in addictive behaviours, including compulsive overeating and alcohol use disorder, and that hyperghrelinemia is associated with such addictive behaviours, ghrelin-responsive circuits may serve as a novel pharmacological target for treatment of alcohol use disorder as well as binge eating.

  1. DESACYL GHRELIN INHIBITS THE OREXIGENIC EFFECT OF PERIPHERALLY INJECTED GHRELIN IN RATS

    OpenAIRE

    Inhoff, Tobias; Mönnikes, Hubert; Noetzel, Steffen; Stengel, Andreas; Goebel, Miriam; Dinh, Q. Thai; Riedl, Andrea; Bannert, Norbert; Wisser, Anna-Sophia; Wiedenmann, Bertram; Klapp, Burghard F.; Taché, Yvette; Kobelt, Peter

    2008-01-01

    Studies showed that the metabolic unlike the neuroendocrine effects of ghrelin could be abrogated by co-administered unacylated ghrelin. The aim was to investigate the interaction between ghrelin and desacyl ghrelin administered intraperitoneally on food intake and neuronal activity (c-Fos) in the arcuate nucleus in non-fasted rats. Ghrelin (13 μg/kg) significantly increased food intake within the first 30 min post injection. Desacyl ghrelin at 64 and 127 μg/kg injected simultaneously with gh...

  2. Ghrelin Partially Protects Against Cisplatin-Induced Male Murine Gonadal Toxicity in a GHSR-1a-Dependent Manner1

    Science.gov (United States)

    Whirledge, Shannon D.; Garcia, Jose M.; Smith, Roy G.; Lamb, Dolores J.

    2015-01-01

    ABSTRACT The chemotherapeutic drug cisplatin causes a number of dose-dependent side effects, including cachexia and testicular damage. Patients receiving a high cumulative dose of cisplatin may develop permanent azoospermia and subsequent infertility. Thus, the development of chemotherapeutic regimens with the optimal postsurvival quality of life (fertility) is of high importance. This study tested the hypothesis that ghrelin administration can prevent or minimize cisplatin-induced testicular damage and cachexia. Ghrelin and its receptor, the growth hormone secretagogue receptor (GHSR-1a), are expressed and function in the testis. Targeted deletion of ghrelin, or its receptor, significantly increases the rate of cell death in the testis, suggesting a protective role. Intraperitoneal administration of vehicle, ghrelin, or cisplatin alone or in combination with ghrelin, in cycles of 9 or 18 days, to adult male C57Bl/6 mice was performed. Body weight was measured daily and testicular and epididymal weight, sperm density and motility, testicular histology, and testicular cell death were analyzed at the time of euthanization. Ghrelin coadministration decreased the severity of cisplatin-induced cachexia and gonadal toxicity. Body, testicular, and epididymal weights significantly increased as testicular cell death decreased with ghrelin coadministration. The widespread damage to the seminiferous epithelium induced by cisplatin administration was less severe in mice simultaneously treated with ghrelin. Furthermore, ghrelin diminished the deleterious effects of cisplatin on testis and body weight homeostasis in wild-type but not Ghsr−/− mice, showing that ghrelin's actions are mediated via GHSR. Ghrelin or more stable GHSR agonists potentially offer a novel therapeutic approach to minimize the testicular damage that occurs after gonadotoxin exposure. PMID:25631345

  3. Central and peripheral des-acyl ghrelin regulates body temperature in rats.

    Science.gov (United States)

    Inoue, Yoshiyuki; Nakahara, Keiko; Maruyama, Keisuke; Suzuki, Yoshiharu; Hayashi, Yujiro; Kangawa, Kenji; Murakami, Noboru

    2013-01-04

    In the present study using rats, we demonstrated that central and peripheral administration of des-acyl ghrelin induced a decrease in the surface temperature of the back, and an increase in the surface temperature of the tail, although the effect of peripheral administration was less marked than that of central administration. Furthermore, these effects of centrally administered des-acyl ghrelin could not be prevented by pretreatment with [D-Lys3]-GHRP-6 GH secretagogue receptor 1a (GHS-R1a) antagonists. Moreover, these actions of des-acyl ghrelin on body temperature were inhibited by the parasympathetic nerve blocker methylscopolamine but not by the sympathetic nerve blocker timolol. Using immunohistochemistry, we confirmed that des-acyl ghrelin induced an increase of cFos expression in the median preoptic nucleus (MnPO). Additionally, we found that des-acyl ghrelin dilated the aorta and tail artery in vitro. These results indicate that centrally administered des-acyl ghrelin regulates body temperature via the parasympathetic nervous system by activating neurons in the MnPO through interactions with a specific receptor distinct from the GHS-R1a, and that peripherally administered des-acyl ghrelin acts on the central nervous system by passing through the blood-brain barrier, whereas it exerts a direct action on the peripheral vascular system. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. Peroxisome Proliferator-Activated Receptor Alpha Target Genes

    Directory of Open Access Journals (Sweden)

    Maryam Rakhshandehroo

    2010-01-01

    Full Text Available The peroxisome proliferator-activated receptor alpha (PPARα is a ligand-activated transcription factor involved in the regulation of a variety of processes, ranging from inflammation and immunity to nutrient metabolism and energy homeostasis. PPARα serves as a molecular target for hypolipidemic fibrates drugs which bind the receptor with high affinity. Furthermore, PPARα binds and is activated by numerous fatty acids and fatty acid-derived compounds. PPARα governs biological processes by altering the expression of a large number of target genes. Accordingly, the specific role of PPARα is directly related to the biological function of its target genes. Here, we present an overview of the involvement of PPARα in lipid metabolism and other pathways through a detailed analysis of the different known or putative PPARα target genes. The emphasis is on gene regulation by PPARα in liver although many of the results likely apply to other organs and tissues as well.

  5. The repertoire of bitter taste receptor genes in canids.

    Science.gov (United States)

    Shang, Shuai; Wu, Xiaoyang; Chen, Jun; Zhang, Huanxin; Zhong, Huaming; Wei, Qinguo; Yan, Jiakuo; Li, Haotian; Liu, Guangshuai; Sha, Weilai; Zhang, Honghai

    2017-07-01

    Bitter taste receptors (Tas2rs) play important roles in mammalian defense mechanisms by helping animals detect and avoid toxins in food. Although Tas2r genes have been widely studied in several mammals, minimal research has been performed in canids. To analyze the genetic basis of Tas2r genes in canids, we first identified Tas2r genes in the wolf, maned wolf, red fox, corsac fox, Tibetan fox, fennec fox, dhole and African hunting dog. A total of 183 Tas2r genes, consisting of 118 intact genes, 6 partial genes and 59 pseudogenes, were detected. Differences in the pseudogenes were observed among nine canid species. For example, Tas2r4 was a pseudogene in the dog but might play a functional role in other canid species. The Tas2r42 and Tas2r10 genes were pseudogenes in the maned wolf and dhole, respectively, and the Tas2r5 and Tas2r34 genes were pseudogenes in the African hunting dog; however, these genes were intact genes in other canid species. The differences in Tas2r pseudogenes among canids might suggest that the loss of intact Tas2r genes in canid species is species-dependent. We further compared the 183 Tas2r genes identified in this study with Tas2r genes from ten additional carnivorous species to evaluate the potential influence of diet on the evolution of the Tas2r gene repertoire. Phylogenetic analysis revealed that most of the Tas2r genes from the 18 species intermingled across the tree, suggesting that Tas2r genes are conserved among carnivores. Within canids, we found that some Tas2r genes corresponded to the traditional taxonomic groupings, while some did not. PIC analysis showed that the number of Tas2r genes in carnivores exhibited no positive correlation with diet composition, which might be due to the limited number of carnivores included in our study.

  6. Evolution of the vertebrate insulin receptor substrate (Irs) gene family.

    Science.gov (United States)

    Al-Salam, Ahmad; Irwin, David M

    2017-06-23

    Insulin receptor substrate (Irs) proteins are essential for insulin signaling as they allow downstream effectors to dock with, and be activated by, the insulin receptor. A family of four Irs proteins have been identified in mice, however the gene for one of these, IRS3, has been pseudogenized in humans. While it is known that the Irs gene family originated in vertebrates, it is not known when it originated and which members are most closely related to each other. A better understanding of the evolution of Irs genes and proteins should provide insight into the regulation of metabolism by insulin. Multiple genes for Irs proteins were identified in a wide variety of vertebrate species. Phylogenetic and genomic neighborhood analyses indicate that this gene family originated very early in vertebrae evolution. Most Irs genes were duplicated and retained in fish after the fish-specific genome duplication. Irs genes have been lost of various lineages, including Irs3 in primates and birds and Irs1 in most fish. Irs3 and Irs4 experienced an episode of more rapid protein sequence evolution on the ancestral mammalian lineage. Comparisons of the conservation of the proteins sequences among Irs paralogs show that domains involved in binding to the plasma membrane and insulin receptors are most strongly conserved, while divergence has occurred in sequences involved in interacting with downstream effector proteins. The Irs gene family originated very early in vertebrate evolution, likely through genome duplications, and in parallel with duplications of other components of the insulin signaling pathway, including insulin and the insulin receptor. While the N-terminal sequences of these proteins are conserved among the paralogs, changes in the C-terminal sequences likely allowed changes in biological function.

  7. Association of ghrelin Leu72Met polymorphism with type 2 diabetes mellitus in Chinese population.

    Science.gov (United States)

    Liu, Jing; Liu, Jia; Tian, Li-min; Liu, Ju-xiang; Bing, Ya-jun; Zhang, Ji-ping; Wang, Yun-Fang; Zhang, Lu-yan

    2012-08-10

    Ghrelin, a novel endogenous ligand for the growth hormone secretagogue receptor, is considered to implicate the development of the type 2 diabetes mellitus (T2DM). The Leu72Met (+408C>A) polymorphism of the preproghrelin, has been linked to obesity, insulin resistance and diabetes. To investigate the distribution of ghrelin gene Leu72Met polymorphism and its association with the type 2 diabetes mellitus in Chinese population. We conducted a case-control study on 877 patients with T2DM and 864 controls, which were genotyped by the polymerase chain reaction (PCR) technique, denaturing high performance liquid chromatography (DHPLC) and DNA sequence analysis. Laboratory analyses were carried out in the hospital laboratory. No significant difference in the Leu72Met genotype distributions and allele frequency was observed between type 2 diabetes mellitus and controls (both P>0.05). The polymorphism was not associated with T2DM. However, among the T2DM group, the patients carrying Leu72Leu genotype had significantly increased levels of FPG and serum creatinine compared with variant genotypes (Leu72Met and Met72Met) (Ppolymorphism of the preproghrelin gene was not associated with T2DM in Chinese population. However, it may have some roles in the etiology of insulin resistance. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Vitamin D receptor and estrogen receptor gene polymorphisms in postmenopausal Danish women

    DEFF Research Database (Denmark)

    Bagger, Y Z; Hassager, C; Heegaard, Anne-Marie

    2000-01-01

    To investigate the polymorphisms of the vitamin D receptor (VDR) and estrogen receptor (ER) genes in relation to biochemical markers of bone turnover (serum osteocalcin and urinary collagen type I degradation products (CrossLaps), and to study ER genotypes in relation to serum lipoproteins, blood...... pressure, or changes in these parameters after 2 years of hormone replacement therapy (HRT) in 499 Danish postmenopausal women....

  9. The Central Nervous System Sites Mediating the Orexigenic Actions of Ghrelin

    Science.gov (United States)

    Mason, B.L.; Wang, Q.; Zigman, J.M.

    2014-01-01

    The peptide hormone ghrelin is important for both homeostatic and hedonic eating behaviors, and its orexigenic actions occur mainly via binding to the only known ghrelin receptor, the growth hormone secretagogue receptor (GHSR). GHSRs are located in several distinct regions of the central nervous system. This review discusses those central nervous system sites that have been found to play critical roles in the orexigenic actions of ghrelin, including hypothalamic nuclei, the hippocampus, the amygdala, the caudal brain stem, and midbrain dopaminergic neurons. Hopefully, this review can be used as a stepping stone for the reader wanting to gain a clearer understanding of the central nervous system sites of direct ghrelin action on feeding behavior, and as inspiration for future studies to provide an even-more-detailed map of the neurocircuitry controlling eating and body weight. PMID:24111557

  10. Ghrelin alleviates anxiety- and depression-like behaviors induced by chronic unpredictable mild stress in rodents.

    Science.gov (United States)

    Huang, Hui-Jie; Zhu, Xiao-Cang; Han, Qiu-Qin; Wang, Ya-Lin; Yue, Na; Wang, Jing; Yu, Rui; Li, Bing; Wu, Gen-Cheng; Liu, Qiong; Yu, Jin

    2017-05-30

    As a regulator of food intake, ghrelin also plays a key role in mood disorders. Previous studies reported that acute ghrelin administration defends against depressive symptoms of chronic stress. However, the effects of long-term ghrelin on rodents under chronic stress hasn't been revealed. In this study, we found chronic peripheral administration of ghrelin (5nmol/kg/day for 2 weeks, i.p.) could alleviate anxiety- and depression-like behaviors induced by chronic unpredictable mild stress (CUMS). The depression-like behaviors were assessed by the forced swimming test (FST), and anxiety-like behaviors were assessed by the open field test (OFT) and the elevated plus maze test (EPM). Meanwhile, we observed that peripheral acylated ghrelin, together with gastral and hippocampal ghrelin prepropeptide mRNA level, were significantly up-regulated in CUMS mice. Besides, the increased protein level of growth hormone secretagogue receptor (GHSR) in hippocampus were also detected. These results suggested that the endogenous ghrelin/GHSR pathway activated by CUMS plays a role in homeostasis. Further results showed that central treatment of ghrelin (10μg/rat/day for 2 weeks, i.c.v.) or GHRP-6 (the agonist of GHSR, 10μg/rat/day for 2 weeks, i.c.v.) significantly alleviated the depression-like behaviors induced by CUMS in FST and sucrose preference test (SPT). Based on these results, we concluded that central GHSR is involved in the antidepressant-like effect of exogenous ghrelin treatment, and ghrelin/GHSR may have the inherent neuromodulatory properties against depressive symptoms. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Ghrelin is an orexigenic and metabolic signaling peptide in the arcuate and paraventricular nuclei.

    Science.gov (United States)

    Currie, Paul J; Mirza, Aaisha; Fuld, Rebecca; Park, Diana; Vasselli, Joseph R

    2005-08-01

    Ghrelin is a 28-amino acid acylated peptide and is the endogenous ligand for the growth hormone secretagogue receptor (GHS-R). The GHS-R is expressed in hypothalamic nuclei, including the arcuate nucleus (Arc) where it is colocalized with neuropeptide Y (NPY) neurons. In the present study, we examined the effects of ghrelin on feeding and energy substrate utilization (respiratory quotient; RQ) following direct injections into either the arcuate or the paraventricular nucleus (PVN) of the hypothalamus. Ghrelin was administered at the beginning of the dark cycle at doses of 15-60 pmol to male and female rats. In feeding studies, food intake was measured 2 and 4 h postinjection. Separate groups of rats were injected with ghrelin, and the RQ (VCO(2)/VO(2)) was measured using an open circuit calorimeter over a 4-h period. Both Arc and PVN injections of ghrelin increased food intake in male and female rats. Ghrelin also increased RQ, reflecting a shift in energy substrate utilization in favor of carbohydrate oxidation. Because these effects are similar to those observed after PVN injection of NPY, we then assessed the impact of coinjecting ghrelin with NPY into the PVN. When rats were pretreated with very low doses of ghrelin (2.5-10 pmol), NPY's (50 pmol) effects on eating and RQ were potentiated. Overall, these data are in agreement with evidence suggesting that ghrelin functions as a gut-brain endocrine hormone implicated in the regulation of food intake and energy metabolism. Our findings are also consistent with a possible interactive role of hypothalamic ghrelin and NPY systems.

  12. Allelic association of the D2 dopamine receptor gene with receptor-binding characteristics in alcoholism

    International Nuclear Information System (INIS)

    Noble, E.P.; Blum, K.; Ritchie, T.; Montgomery, A.; Sheridan, P.J.

    1991-01-01

    The allelic association of the human D2 dopamine receptor gene with the binding characteristics of the D2 dopamine receptor was determined in 66 brains of alcoholic and non-alcoholic subjects. In a blinded experiment, DNA from the cerebral cortex was treated with the restriction endonuclease Taql and probed with a 1.5-kilobase (kb) digest of a clone (lambda hD2G1) of the human D2 dopamine receptor gene. The binding characteristics (Kd [binding affinity] and Bmax [number of binding sites]) of the D2 dopamine receptor were determined in the caudate nuclei of these brains using tritiated spiperone as the ligand. The adjusted Kd was significantly lower in alcoholic than in nonalcoholic subjects. In subjects with the A1 allele, in whom a high association with alcoholism was found, the Bmax was significantly reduced compared with the Bmax of subjects with the A2 allele. Moreover, a progressively reduced Bmax was found in subjects with A2/A2, A1/A2, and A1/A1 alleles, with subjects with A2/A2 having the highest mean values, and subjects with A1/A1, the lowest. The polymorphic pattern of the D2 dopamine receptor gene and its differential expression of receptors suggests the involvement of the dopaminergic system in conferring susceptibility to at least one subtype of severe alcoholism

  13. Association between vitamin D receptor gene polymorphism (TaqI ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics; Volume 94; Issue 3. Association between vitamin D receptor gene polymorphism (TaqI) and obesity in Chinese population. Hui-Ru Fan Li-Qun Lin Hao Ma Ying Li Chang-Hao Sun. Research Note Volume 94 Issue 3 September 2015 pp 473-478 ...

  14. Genetic diversity of bitter taste receptor gene family in Sichuan

    Indian Academy of Sciences (India)

    Genetic diversity of bitter taste receptor gene family in Sichuan domestic and Tibetan chicken populations. YUAN SU DIYAN LI UMA GAUR YAN WANG NAN WU BINLONG CHEN HONGXIAN XU HUADONG YIN YAODONG HU QING ZHU. RESEARCH ARTICLE Volume 95 Issue 3 September 2016 pp 675-681 ...

  15. Three novel and two known androgen receptor gene mutations ...

    Indian Academy of Sciences (India)

    gene mutations associated with androgen insensitivity syndrome in sex-reversed XY female patients. J. Genet. ... signal and a C-terminal. Keywords. androgen insensitivity syndrome; androgen receptor; truncation mutation; N-terminal domain; XY sex reversal. .... and an increased risk of gonadal tumour. Mutations in SRY.

  16. Association between vitamin D receptor gene polymorphism (TaqI)

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics; Volume 94; Issue 3. Association between vitamin D receptor gene polymorphism (TaqI) and obesity in Chinese population. Hui-Ru Fan Li-Qun Lin Hao Ma Ying Li Chang-Hao Sun. Research Note Volume 94 Issue 3 September 2015 pp 473-478 ...

  17. Genetic diversity of bitter taste receptor gene family in Sichuan ...

    Indian Academy of Sciences (India)

    Previous research had revealed that chicken has only three bitter taste receptor genes (Tas2r1, ... Journal of Genetics, DOI 10.1007/s12041-016-0684-4, Vol. ..... between red-winged blackbirds and European starlings. ... Academic Press,.

  18. Changes in Subcellular Distribution of n-Octanoyl or n-Decanoyl Ghrelin in Ghrelin-Producing Cells

    OpenAIRE

    Nishi, Yoshihiro; Mifune, Hiroharu; Yabuki, Akira; Tajiri, Yuji; Hirata, Rumiko; Tanaka, Eiichiro; Hosoda, Hiroshi; Kangawa, Kenji; Kojima, Masayasu

    2013-01-01

    Background: The enzyme ghrelin O-acyltransferase (GOAT) catalyzes the acylation of ghrelin. The molecular form of GOAT, together with its reaction in vitro, has been reported previously. However, the sub-cellular processes governing the acylation of ghrelin remain to be elucidated.Methods: Double immunoelectron microscopy was used to examine changes in the relative proportions of secretory granules containing n-octanoyl ghrelin (C8-ghrelin) or n-decanoyl ghrelin (C10-ghrelin) in ghrelin-pro...

  19. Role of ghrelin in drug abuse and reward-relevant behaviors: a burgeoning field and gaps in the literature.

    Science.gov (United States)

    Revitsky, A R; Klein, L C

    2013-09-01

    Ghrelin is a gut-brain hormone that regulates energy balance through food consumption. While ghrelin is well known for its role in hypothalamic activation and homeostatic feeding, more recent evidence suggests that ghrelin also is involved in hedonic feeding through the dopaminergic reward pathway. This paper investigated how ghrelin administration (intraperitoneal, intracerebroventricular, or directly into dopaminergic reward-relevant brain regions) activates the dopaminergic reward pathway and associated reward-relevant behavioral responses in rodents. A total of 19 empirical publications that examined one or more of these variables were included in this review. Overall, ghrelin administration increases dopamine levels in the nucleus accumbens, as well as reward-relevant behaviors such as food (both standard chow and palatable foods) and alcohol consumption. Ghrelin administration also increases operant responding for sucrose, and conditioned place preference. Following a review of the small body of literature examining the effects of ghrelin administration on the dopamine reward pathway, we present a model of the relationship between ghrelin and dopaminergic reward activation. Specifically, ghrelin acts on ghrelin receptors (GHS-R1A) in the ventral tegmental area (VTA) and lateral dorsal tegmental nucleus (LDTg) to stimulate the mesolimbic dopamine reward pathway, which results in increased rewarding behaviors in rodents. Results from this review suggest that selective antagonism of the ghrelin system may serve as potential treatment for addictive drug use. This review highlights gaps in the literature, including a lack of examination of sex- or age-related differences in the effects of ghrelin on dopamine reward processes. In light of vulnerability to drug abuse among female and adolescent populations, future studies should target these individual difference factors.

  20. A concerted kinase interplay identifies PPARgamma as a molecular target of ghrelin signaling in macrophages.

    Directory of Open Access Journals (Sweden)

    Annie Demers

    2009-11-01

    Full Text Available The peroxisome proliferator-activator receptor PPARgamma plays an essential role in vascular biology, modulating macrophage function and atherosclerosis progression. Recently, we have described the beneficial effect of combined activation of the ghrelin/GHS-R1a receptor and the scavenger receptor CD36 to induce macrophage cholesterol release through transcriptional activation of PPARgamma. Although the interplay between CD36 and PPARgamma in atherogenesis is well recognized, the contribution of the ghrelin receptor to regulate PPARgamma remains unknown. Here, we demonstrate that ghrelin triggers PPARgamma activation through a concerted signaling cascade involving Erk1/2 and Akt kinases, resulting in enhanced expression of downstream effectors LXRalpha and ABC sterol transporters in human macrophages. These effects were associated with enhanced PPARgamma phosphorylation independently of the inhibitory conserved serine-84. Src tyrosine kinase Fyn was identified as being recruited to GHS-R1a in response to ghrelin, but failure of activated Fyn to enhance PPARgamma Ser-84 specific phosphorylation relied on the concomitant recruitment of docking protein Dok-1, which prevented optimal activation of the Erk1/2 pathway. Also, substitution of Ser-84 preserved the ghrelin-induced PPARgamma activity and responsiveness to Src inhibition, supporting a mechanism independent of Ser-84 in PPARgamma response to ghrelin. Consistent with this, we found that ghrelin promoted the PI3-K/Akt pathway in a Galphaq-dependent manner, resulting in Akt recruitment to PPARgamma, enhanced PPARgamma phosphorylation and activation independently of Ser-84, and increased expression of LXRalpha and ABCA1/G1. Collectively, these results illustrate a complex interplay involving Fyn/Dok-1/Erk and Galphaq/PI3-K/Akt pathways to transduce in a concerted manner responsiveness of PPARgamma to ghrelin in macrophages.

  1. Ghrelin increases the motivation to eat, but does not alter food palatability

    Science.gov (United States)

    Overduin, Joost; Figlewicz, Dianne P.; Bennett-Jay, Jennifer; Kittleson, Sepideh

    2012-01-01

    Homeostatic eating cannot explain overconsumption of food and pathological weight gain. A more likely factor promoting excessive eating is food reward and its representation in the central nervous system (CNS). The anorectic hormones leptin and insulin reduce food reward and inhibit related CNS reward pathways. Conversely, the orexigenic gastrointestinal hormone ghrelin activates both homeostatic and reward-related neurocircuits. The current studies were conducted to identify in rats the effects of intracerebroventricular ghrelin infusions on two distinct aspects of food reward: hedonic valuation (i.e., “liking”) and the motivation to self-administer (i.e., “wanting”) food. To assess hedonic valuation of liquid food, lick motor patterns were recorded using lickometry. Although ghrelin administration increased energy intake, it did not alter the avidity of licking (initial lick rates or lick-cluster size). Several positive-control conditions ruled out lick-rate ceiling effects. Similarly, when the liquid diet was hedonically devalued with quinine supplementation, ghrelin failed to reverse the quinine-associated reduction of energy intake and avidity of licking. The effects of ghrelin on rats' motivation to eat were assessed using lever pressing to self-administer food in a progressive-ratio paradigm. Ghrelin markedly increased motivation to eat, to levels comparable to or greater than those seen following 24 h of food deprivation. Pretreatment with the dopamine D1 receptor antagonist SCH-23390 eliminated ghrelin-induced increases in lever pressing, without compromising generalized licking motor control, indicating a role for D1 signaling in ghrelin's motivational feeding effects. These results indicate that ghrelin increases the motivation to eat via D1 receptor-dependent mechanisms, without affecting perceived food palatability. PMID:22673784

  2. A Natural Variant of Obestatin, Q90L, Inhibits Ghrelin's Action on Food Intake and GH Secretion and Targets NPY and GHRH Neurons in Mice

    OpenAIRE

    Hassouna, Rim; Zizzari, Philippe; Viltart, Odile; Yang, Seung-Kwon; Gardette, Robert; Videau, Catherine; Badoer, Emilio; Epelbaum, Jacques; Tolle, Virginie

    2012-01-01

    BACKGROUND: Ghrelin and obestatin are two gut-derived peptides originating from the same ghrelin/obestatin prepropeptide gene (GHRL). While ghrelin stimulates growth hormone (GH) secretion and food intake and inhibits γ-aminobutyric-acid synaptic transmission onto GHRH (Growth Hormone Releasing Hormone) neurons, obestatin blocks these effects. In Humans, GHRL gene polymorphisms have been associated with pathologies linked to an unbalanced energy homeostasis. We hypothesized that one polymorph...

  3. Gene specific actions of thyroid hormone receptor subtypes.

    Directory of Open Access Journals (Sweden)

    Jean Z Lin

    Full Text Available There are two homologous thyroid hormone (TH receptors (TRs α and β, which are members of the nuclear hormone receptor (NR family. While TRs regulate different processes in vivo and other highly related NRs regulate distinct gene sets, initial studies of TR action revealed near complete overlaps in their actions at the level of individual genes. Here, we assessed the extent that TRα and TRβ differ in target gene regulation by comparing effects of equal levels of stably expressed exogenous TRs +/- T(3 in two cell backgrounds (HepG2 and HeLa. We find that hundreds of genes respond to T(3 or to unliganded TRs in both cell types, but were not able to detect verifiable examples of completely TR subtype-specific gene regulation. TR actions are, however, far from identical and we detect TR subtype-specific effects on global T(3 response kinetics in HepG2 cells and many examples of TR subtype specificity at the level of individual genes, including effects on magnitude of response to TR +/- T(3, TR regulation patterns and T(3 dose response. Cycloheximide (CHX treatment confirms that at least some differential effects involve verifiable direct TR target genes. TR subtype/gene-specific effects emerge in the context of widespread variation in target gene response and we suggest that gene-selective effects on mechanism of TR action highlight differences in TR subtype function that emerge in the environment of specific genes. We propose that differential TR actions could influence physiologic and pharmacologic responses to THs and selective TR modulators (STRMs.

  4. CRDB: database of chemosensory receptor gene families in vertebrate.

    Directory of Open Access Journals (Sweden)

    Dong Dong

    Full Text Available Chemosensory receptors (CR are crucial for animals to sense the environmental changes and survive on earth. The emergence of whole-genome sequences provides us an opportunity to identify the entire CR gene repertoires. To completely gain more insight into the evolution of CR genes in vertebrates, we identified the nearly all CR genes in 25 vertebrates using homology-based approaches. Among these CR gene repertoires, nearly half of them were identified for the first time in those previously uncharacterized species, such as the guinea pig, giant panda and elephant, etc. Consistent with previous findings, we found that the numbers of CR genes vary extensively among different species, suggesting an extreme form of 'birth-and-death' evolution. For the purpose of facilitating CR gene analysis, we constructed a database with the goals to provide a resource for CR genes annotation and a web tool for exploring their evolutionary patterns. Besides a search engine for the gene extraction from a specific chromosome region, an easy-to-use phylogenetic analysis tool was also provided to facilitate online phylogeny study of CR genes. Our work can provide a rigorous platform for further study on the evolution of CR genes in vertebrates.

  5. Genetic variation of the ghrelin signalling system in individuals with amphetamine dependence.

    Science.gov (United States)

    Suchankova, Petra; Jerlhag, Elisabet; Jayaram-Lindström, Nitya; Nilsson, Staffan; Toren, Kjell; Rosengren, Annika; Engel, Jörgen A; Franck, Johan

    2013-01-01

    The development of amphetamine dependence largely depends on the effects of amphetamine in the brain reward systems. Ghrelin, an orexigenic peptide, activates the reward systems and is required for reward induced by alcohol, nicotine, cocaine and amphetamine in mice. Human genetic studies have shown that polymorphisms in the pre-proghrelin (GHRL) as well as GHS-R1A (GHSR) genes are associated with high alcohol consumption, increased weight and smoking in males. Since the heritability factor underlying drug dependence is shared between different drugs of abuse, we here examine the association between single nucleotide polymorphisms (SNPs) and haplotypes in the GHRL and GHSR, and amphetamine dependence. GHRL and GHSR SNPs were genotyped in Swedish amphetamine dependent individuals (n = 104) and controls from the general population (n = 310). A case-control analysis was performed and SNPs and haplotypes were additionally tested for association against Addiction Severity Interview (ASI) composite score of drug use. The minor G-allele of the GHSR SNP rs2948694, was more common among amphetamine dependent individuals when compared to controls (pc  = 0.02). A significant association between the GHRL SNP rs4684677 and ASI composite score of drug use was also reported (pc  = 0.03). The haplotype analysis did not add to the information given by the individual polymorphisms. Although genetic variability of the ghrelin signalling system is not a diagnostic marker for amphetamine dependence and problem severity of drug use, the present results strengthen the notion that ghrelin and its receptor may be involved in the development of addictive behaviours and may thus serve as suitable targets for new treatments of such disorders.

  6. Genetic variation of the ghrelin signalling system in individuals with amphetamine dependence.

    Directory of Open Access Journals (Sweden)

    Petra Suchankova

    Full Text Available The development of amphetamine dependence largely depends on the effects of amphetamine in the brain reward systems. Ghrelin, an orexigenic peptide, activates the reward systems and is required for reward induced by alcohol, nicotine, cocaine and amphetamine in mice. Human genetic studies have shown that polymorphisms in the pre-proghrelin (GHRL as well as GHS-R1A (GHSR genes are associated with high alcohol consumption, increased weight and smoking in males. Since the heritability factor underlying drug dependence is shared between different drugs of abuse, we here examine the association between single nucleotide polymorphisms (SNPs and haplotypes in the GHRL and GHSR, and amphetamine dependence. GHRL and GHSR SNPs were genotyped in Swedish amphetamine dependent individuals (n = 104 and controls from the general population (n = 310. A case-control analysis was performed and SNPs and haplotypes were additionally tested for association against Addiction Severity Interview (ASI composite score of drug use. The minor G-allele of the GHSR SNP rs2948694, was more common among amphetamine dependent individuals when compared to controls (pc  = 0.02. A significant association between the GHRL SNP rs4684677 and ASI composite score of drug use was also reported (pc  = 0.03. The haplotype analysis did not add to the information given by the individual polymorphisms. Although genetic variability of the ghrelin signalling system is not a diagnostic marker for amphetamine dependence and problem severity of drug use, the present results strengthen the notion that ghrelin and its receptor may be involved in the development of addictive behaviours and may thus serve as suitable targets for new treatments of such disorders.

  7. Association of the Leu72Met polymorphism of the ghrelin gene with the risk of Type 2 diabetes in subjects with impaired glucose tolerance in the Finnish Diabetes Prevention Study.

    Science.gov (United States)

    Mager, U; Lindi, V; Lindström, J; Eriksson, J G; Valle, T T; Hämäläinen, H; Ilanne-Parikka, P; Keinänen-Kiukaanniemi, S; Tuomilehto, J; Laakso, M; Pulkkinen, L; Uusitupa, M

    2006-06-01

    Ghrelin is a gut-brain regulatory peptide stimulating appetite and controlling energy balance. In previous studies, the Leu72Met polymorphism of the ghrelin gene has been associated with obesity and impaired insulin secretion. We investigated whether the Leu72Met polymorphism is associated with the incidence of Type 2 diabetes in subjects with impaired glucose tolerance (IGT) participating in the Finnish Diabetes Prevention Study (DPS). DPS was a longitudinal intervention study carried out in five participating centres in Finland. A total of 522 subjects with IGT were randomized into either an intervention or a control group and DNA was available from 507 subjects. The Leu72Met polymorphism was screened by the restriction fragment length polymorphism method. There were no differences in clinical and anthropometric characteristics among the genotypes at baseline. IGT subjects with the Met72 allele were at higher risk of developing Type 2 diabetes than subjects with the Leu72Leu genotype (P = 0.046). Our data also demonstrated that IGT subjects with the common Leu72Leu genotype developed Type 2 diabetes less frequently under intervention circumstances than subjects with the Met72 allele (OR = 0.28, 95% CI 0.10-0.79; P = 0.016). Subjects with the Leu72Leu genotype had a lower risk for the development of Type 2 diabetes. This was observed particularly in the study subjects who underwent an intensive diet and exercise intervention. Defective first-phase insulin secretion related to the Met72 allele might be one factor contributing to the conversion to Type 2 diabetes.

  8. Clarifying the Ghrelin System’s Ability to Regulate Feeding Behaviours Despite Enigmatic Spatial Separation of the GHSR and Its Endogenous Ligand

    Directory of Open Access Journals (Sweden)

    Alexander Edwards

    2017-04-01

    Full Text Available Ghrelin is a hormone predominantly produced in and secreted from the stomach. Ghrelin is involved in many physiological processes including feeding, the stress response, and in modulating learning, memory and motivational processes. Ghrelin does this by binding to its receptor, the growth hormone secretagogue receptor (GHSR, a receptor found in relatively high concentrations in hypothalamic and mesolimbic brain regions. While the feeding and metabolic effects of ghrelin can be explained by the effects of this hormone on regions of the brain that have a more permeable blood brain barrier (BBB, ghrelin produced within the periphery demonstrates a limited ability to reach extrahypothalamic regions where GHSRs are expressed. Therefore, one of the most pressing unanswered questions plaguing ghrelin research is how GHSRs, distributed in brain regions protected by the BBB, are activated despite ghrelin’s predominant peripheral production and poor ability to transverse the BBB. This manuscript will describe how peripheral ghrelin activates central GHSRs to encourage feeding, and how central ghrelin synthesis and ghrelin independent activation of GHSRs may also contribute to the modulation of feeding behaviours.

  9. Mu Opioid Receptor Gene: New Point Mutations in Opioid Addicts

    Directory of Open Access Journals (Sweden)

    Amin Dinarvand

    2014-02-01

    Full Text Available Introduction: Association between single-nucleotide polymorphisms (SNPs in mu opioid receptor gene and drug addiction has been shown in various studies. Here, we have evaluated the existence of polymorphisms in exon 3 of this gene in Iranian population and investigated the possible association between these mutations and opioid addiction.  Methods: 79 opioid-dependent subjects (55 males, 24 females and 134 non-addict or control individuals (74 males, 60 females participated in the study. Genomic DNA was extracted from volunteers’ peripheral blood and exon 3 of the mu opioid receptor gene was amplified by polymerase chain reaction (PCR whose products were then sequenced.  Results: Three different heterozygote polymorphisms were observed in 3 male individuals: 759T>C and 877G>A mutations were found in 2 control volunteers and 1043G>C substitution was observed in an opioid-addicted subject. Association between genotype and opioid addiction for each mutation was not statistically significant.  Discussion: It seems that the sample size used in our study is not enough to confirm or reject any association between 759T>C, 877G>A and 1043G>C substitutions in exon 3 of the mu opioid receptor gene and opioid addiction susceptibility in Iranian population.

  10. Ghrelin inhibits the apoptosis of MC3T3-E1 cells through ERK and AKT signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Qiu-Hua; Liu, Yuan; Wu, Shan-Shan; Cui, Rong-Rong; Yuan, Ling-Qing, E-mail: allenylq@hotmail.com; Liao, Er-Yuan, E-mail: eyliao@21cn.com

    2013-11-01

    Ghrelin is a 28-amino-acid peptide that acts as a natural endogenous ligand of the growth hormone secretagogue receptor (GHSR) and strongly stimulates the release of growth hormone from the hypothalamus–pituitary axis. Previous studies have identified the important physiological effects of ghrelin on bone metabolism, such as regulating proliferation and differentiation of osteoblasts, independent of GH/IGF-1 axis. However, research on effects and mechanisms of ghrelin on osteoblast apoptosis is still rare. In this study, we identified expression of GHSR in MC3T3-E1 cells and determined the effects of ghrelin on the apoptosis of osteoblastic MC3T3-E1 cells and the mechanism involved. Our data demonstrated that ghrelin inhibited the apoptosis of osteoblastic MC3T3-E1 cells induced by serum deprivation, as determined by terminal deoxynucleotidyl transferase-mediated deoxyribonucleotide triphosphate nick end-labeling (TUNEL) and ELISA assays. Moreover, ghrelin upregulated Bcl-2 expression and downregulated Bax expression in a dose-dependent manner. Our study also showed decreased activated caspase-3 activity under the treatment of ghrelin. Further study suggested that ghrelin stimulated the phosphorylation of ERK and AKT. Pretreatment of cells with the ERK inhibitor PD98059, PI3K inhibitor LY294002, and GHSR-siRNA blocked the ghrelin-induced activation of ERK and AKT, respectively; however, ghrelin did not stimulate the phosphorylation of p38 or JNK. PD90859, LY294002 and GHSR-siRNA attenuated the anti-apoptosis effect of ghrelin in MC3T3-E1 cells. In conclusion, ghrelin inhibits the apoptosis of osteoblastic MC3T3-E1 cells induced by serum deprivation, which may be mediated by activating the GHSR/ERK and GHSR/PI3K/AKT signaling pathways. - Highlights: • We explored the effects of ghrelin on serum deprivation-induced MC3T3-E1 cells apoptosis. • Both ELISA and TUNEL were used to detect the apoptosis. • The receptor of ghrelin, GHSR, was expressed in MC3T3-E1

  11. Ghrelin inhibits the apoptosis of MC3T3-E1 cells through ERK and AKT signaling pathway

    International Nuclear Information System (INIS)

    Liang, Qiu-Hua; Liu, Yuan; Wu, Shan-Shan; Cui, Rong-Rong; Yuan, Ling-Qing; Liao, Er-Yuan

    2013-01-01

    Ghrelin is a 28-amino-acid peptide that acts as a natural endogenous ligand of the growth hormone secretagogue receptor (GHSR) and strongly stimulates the release of growth hormone from the hypothalamus–pituitary axis. Previous studies have identified the important physiological effects of ghrelin on bone metabolism, such as regulating proliferation and differentiation of osteoblasts, independent of GH/IGF-1 axis. However, research on effects and mechanisms of ghrelin on osteoblast apoptosis is still rare. In this study, we identified expression of GHSR in MC3T3-E1 cells and determined the effects of ghrelin on the apoptosis of osteoblastic MC3T3-E1 cells and the mechanism involved. Our data demonstrated that ghrelin inhibited the apoptosis of osteoblastic MC3T3-E1 cells induced by serum deprivation, as determined by terminal deoxynucleotidyl transferase-mediated deoxyribonucleotide triphosphate nick end-labeling (TUNEL) and ELISA assays. Moreover, ghrelin upregulated Bcl-2 expression and downregulated Bax expression in a dose-dependent manner. Our study also showed decreased activated caspase-3 activity under the treatment of ghrelin. Further study suggested that ghrelin stimulated the phosphorylation of ERK and AKT. Pretreatment of cells with the ERK inhibitor PD98059, PI3K inhibitor LY294002, and GHSR-siRNA blocked the ghrelin-induced activation of ERK and AKT, respectively; however, ghrelin did not stimulate the phosphorylation of p38 or JNK. PD90859, LY294002 and GHSR-siRNA attenuated the anti-apoptosis effect of ghrelin in MC3T3-E1 cells. In conclusion, ghrelin inhibits the apoptosis of osteoblastic MC3T3-E1 cells induced by serum deprivation, which may be mediated by activating the GHSR/ERK and GHSR/PI3K/AKT signaling pathways. - Highlights: • We explored the effects of ghrelin on serum deprivation-induced MC3T3-E1 cells apoptosis. • Both ELISA and TUNEL were used to detect the apoptosis. • The receptor of ghrelin, GHSR, was expressed in MC3T3-E1

  12. Structural determination and histochemical localization of ghrelin in the red-eared slider turtle, Trachemys scripta elegans.

    Science.gov (United States)

    Kaiya, Hiroyuki; Sakata, Ichiro; Kojima, Masayasu; Hosoda, Hiroshi; Sakai, Takafumi; Kangawa, Kenji

    2004-08-01

    We purified ghrelin peptide and determined the cDNA sequence encoding the precursor protein from the stomach of the red-eared slider turtle, Trachemys scripta elegans. The Trachemys ghrelin is comprised of 25-amino acids and has the sequence GSSFLSPEYQNTQQRKDPKKHTKLN. The third serine residue was modified by n-octanoic (C8:0), decanoic (C10:0) or unsaturated decanoic acid (C10:1). The carboxyl-terminal end of the peptide was not amidated, as seen in the ghrelins of other land vertebrates. Quantitative real-time PCR analysis revealed high levels of gene expression in the stomach and moderate levels in the large intestine and pancreas. Histochemical studies of turtle stomach revealed that ghrelin-immunopositive (ghrelin-ip) cells, which were small and round, were observed in the mucosal layer of the stomach but not in the myenteric plexus, and ghrelin-mRNA-expressing (ghrelin-ex) cells detected by in situ hybridization were scattered in a similar distribution as ghrelin-ip cells. These results indicate that ghrelin is present in reptiles.

  13. Identification of novel androgen receptor target genes in prostate cancer

    Directory of Open Access Journals (Sweden)

    Gerald William L

    2007-06-01

    Full Text Available Abstract Background The androgen receptor (AR plays critical roles in both androgen-dependent and castrate-resistant prostate cancer (PCa. However, little is known about AR target genes that mediate the receptor's roles in disease progression. Results Using Chromatin Immunoprecipitation (ChIP Display, we discovered 19 novel loci occupied by the AR in castrate resistant C4-2B PCa cells. Only four of the 19 AR-occupied regions were within 10-kb 5'-flanking regulatory sequences. Three were located up to 4-kb 3' of the nearest gene, eight were intragenic and four were in gene deserts. Whereas the AR occupied the same loci in C4-2B (castrate resistant and LNCaP (androgen-dependent PCa cells, differences between the two cell lines were observed in the response of nearby genes to androgens. Among the genes strongly stimulated by DHT in C4-2B cells – D-dopachrome tautomerase (DDT, Protein kinase C delta (PRKCD, Glutathione S- transferase theta 2 (GSTT2, Transient receptor potential cation channel subfamily V member 3 (TRPV3, and Pyrroline-5-carboxylate reductase 1 (PYCR1 – most were less strongly or hardly stimulated in LNCaP cells. Another AR target gene, ornithine aminotransferase (OAT, was AR-stimulated in a ligand-independent manner, since it was repressed by AR siRNA knockdown, but not stimulated by DHT. We also present evidence for in vivo AR-mediated regulation of several genes identified by ChIP Display. For example, PRKCD and PYCR1, which may contribute to PCa cell growth and survival, are expressed in PCa biopsies from primary tumors before and after ablation and in metastatic lesions in a manner consistent with AR-mediated stimulation. Conclusion AR genomic occupancy is similar between LNCaP and C4-2B cells and is not biased towards 5' gene flanking sequences. The AR transcriptionally regulates less than half the genes nearby AR-occupied regions, usually but not always, in a ligand-dependent manner. Most are stimulated and a few are

  14. Potentiation of ghrelin signaling attenuates cancer anorexia–cachexia and prolongs survival

    Science.gov (United States)

    Fujitsuka, N; Asakawa, A; Uezono, Y; Minami, K; Yamaguchi, T; Niijima, A; Yada, T; Maejima, Y; Sedbazar, U; Sakai, T; Hattori, T; Kase, Y; Inui, A

    2011-01-01

    Cancer anorexia–cachexia syndrome is characterized by decreased food intake, weight loss, muscle tissue wasting and psychological distress, and this syndrome is a major source of increased morbidity and mortality in cancer patients. This study aimed to clarify the gut–brain peptides involved in the pathogenesis of the syndrome and determine effective treatment for cancer anorexia–cachexia. We show that both ghrelin insufficiency and resistance were observed in tumor-bearing rats. Corticotropin-releasing factor (CRF) decreased the plasma level of acyl ghrelin, and its receptor antagonist, α-helical CRF, increased food intake of these rats. The serotonin 2c receptor (5-HT2cR) antagonist SB242084 decreased hypothalamic CRF level and improved anorexia, gastrointestinal (GI) dysmotility and body weight loss. The ghrelin receptor antagonist (D-Lys3)-GHRP-6 worsened anorexia and hastened death in tumor-bearing rats. Ghrelin attenuated anorexia–cachexia in the short term, but failed to prolong survival, as did SB242084 administration. In addition, the herbal medicine rikkunshito improved anorexia, GI dysmotility, muscle wasting, and anxiety-related behavior and prolonged survival in animals and patients with cancer. The appetite-stimulating effect of rikkunshito was blocked by (D-Lys3)-GHRP-6. Active components of rikkunshito, hesperidin and atractylodin, potentiated ghrelin secretion and receptor signaling, respectively, and atractylodin prolonged survival in tumor-bearing rats. Our study demonstrates that the integrated mechanism underlying cancer anorexia–cachexia involves lowered ghrelin signaling due to excessive hypothalamic interactions of 5-HT with CRF through the 5-HT2cR. Potentiation of ghrelin receptor signaling may be an attractive treatment for anorexia, muscle wasting and prolong survival in patients with cancer anorexia–cachexia. PMID:22832525

  15. Dynamic evolution of bitter taste receptor genes in vertebrates

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    Jones Gareth

    2009-01-01

    Full Text Available Abstract Background Sensing bitter tastes is crucial for many animals because it can prevent them from ingesting harmful foods. This process is mainly mediated by the bitter taste receptors (T2R, which are largely expressed in the taste buds. Previous studies have identified some T2R gene repertoires, and marked variation in repertoire size has been noted among species. However, the mechanisms underlying the evolution of vertebrate T2R genes remain poorly understood. Results To better understand the evolutionary pattern of these genes, we identified 16 T2R gene repertoires based on the high coverage genome sequences of vertebrates and studied the evolutionary changes in the number of T2R genes during birth-and-death evolution using the reconciled-tree method. We found that the number of T2R genes and the fraction of pseudogenes vary extensively among species. Based on the results of phylogenetic analysis, we showed that T2R gene families in teleost fishes are more diverse than those in tetrapods. In addition to the independent gene expansions in teleost fishes, frogs and mammals, lineage-specific gene duplications were also detected in lizards. Furthermore, extensive gains and losses of T2R genes were detected in each lineage during their evolution, resulting in widely differing T2R gene repertoires. Conclusion These results further support the hypotheses that T2R gene repertoires are closely related to the dietary habits of different species and that birth-and-death evolution is associated with adaptations to dietary changes.

  16. Replicated Risk Nicotinic Cholinergic Receptor Genes for Nicotine Dependence

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    Lingjun Zuo

    2016-11-01

    Full Text Available It has been hypothesized that the nicotinic acetylcholine receptors (nAChRs play important roles in nicotine dependence (ND and influence the number of cigarettes smoked per day (CPD in smokers. We compiled the associations between nicotinic cholinergic receptor genes (CHRNs and ND/CPD that were replicated across different studies, reviewed the expression of these risk genes in human/mouse brains, and verified their expression using independent samples of both human and mouse brains. The potential functions of the replicated risk variants were examined using cis-eQTL analysis or predicted using a series of bioinformatics analyses. We found replicated and significant associations for ND/CPD at 19 SNPs in six genes in three genomic regions (CHRNB3-A6, CHRNA5-A3-B4 and CHRNA4. These six risk genes are expressed in at least 18 distinct areas of the human/mouse brain, with verification in our independent human and mouse brain samples. The risk variants might influence the transcription, expression and splicing of the risk genes, alter RNA secondary or protein structure. We conclude that the replicated associations between CHRNB3-A6, CHRNA5-A3-B4, CHRNA4 and ND/CPD are very robust. More research is needed to examine how these genetic variants contribute to the risk for ND/CPD.

  17. The GOAT-ghrelin system is not essential for hypoglycemia prevention during prolonged calorie restriction.

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    Chun-Xia Yi

    Full Text Available Ghrelin acylation by ghrelin O-acyltransferase (GOAT has recently been reported to be essential for the prevention of hypoglycemia during prolonged negative energy balance. Using a unique set of four different genetic loss-of-function models for the GOAT/ghrelin/growth hormone secretagogue receptor (GHSR system, we thoroughly tested the hypothesis that lack-of-ghrelin activation or signaling would lead to hypoglycemia during caloric deprivation.Male and female knockout (KO mice for GOAT, ghrelin, GHSR, or both ghrelin and GHSR (dKO were subjected to prolonged calorie restriction (40% of ad libitum chow intake. Body weight, fat mass, and glucose levels were recorded daily and compared to wildtype (WT controls. Forty-eight hour blood glucose profiles were generated for each individual mouse when 2% or less body fat mass was reached. Blood samples were obtained for analysis of circulating levels of acyl- and desacyl-ghrelin, IGF-1, and insulin.Chronic calorie restriction progressively decreased body weight and body fat mass in all mice regardless of genotype. When fat mass was depleted to 2% or less of body weight for 2 consecutive days, random hypoglycemic events occurred in some mice across all genotypes. There was no increase in the incidence of hypoglycemia in any of the four loss-of-function models for ghrelin signaling including GOAT KO mice. Furthermore, no differences in insulin or IGF-1 levels were observed between genotypes.The endogenous GOAT-ghrelin-GHSR system is not essential for the maintenance of euglycemia during prolonged calorie restriction.

  18. Ghrelin in the CNS: from hunger to a rewarding and memorable meal?

    Science.gov (United States)

    Olszewski, Pawel K; Schiöth, Helgi B; Levine, Allen S

    2008-06-01

    Ghrelin, the endogenous agonist of the growth hormone secretagogue receptor, has been shown to induce robust feeding responses in numerous experimental models. Although ghrelin comes from both peripheral and central sources, its hyperphagic properties, to a large extent, arise from activity at the brain level. The current review focuses on describing central mechanisms through which this peptide affects consumption. We address the issue of whether ghrelin serves just as a signal of energy needs of the organism or - as suggested by the most recent findings - also affects food intake via other feeding-related mechanisms, including reward and memory. Complexity of ghrelin's role in the regulation of ingestive behavior is discussed by characterizing its influence on consumption, reward and memory as well as by defining its function within the brain circuitry and interplay with other neuropeptides.

  19. Neuroprotective Actions of Ghrelin and Growth Hormone Secretagogues

    Science.gov (United States)

    Frago, Laura M.; Baquedano, Eva; Argente, Jesús; Chowen, Julie A.

    2011-01-01

    The brain incorporates and coordinates information based on the hormonal environment, receiving information from peripheral tissues through the circulation. Although it was initially thought that hormones only acted on the hypothalamus to perform endocrine functions, it is now known that they in fact exert diverse actions on many different brain regions including the hypothalamus. Ghrelin is a gastric hormone that stimulates growth hormone secretion and food intake to regulate energy homeostasis and body weight by binding to its receptor, growth hormone secretagogues–GH secretagogue-receptor, which is most highly expressed in the pituitary and hypothalamus. In addition, ghrelin has effects on learning and memory, reward and motivation, anxiety, and depression, and could be a potential therapeutic agent in neurodegenerative disorders where excitotoxic neuronal cell death and inflammatory processes are involved. PMID:21994488

  20. Retinoid X receptor and peroxisome proliferator-activated receptor activate an estrogen responsive gene independent of the estrogen receptor.

    Science.gov (United States)

    Nuñez, S B; Medin, J A; Braissant, O; Kemp, L; Wahli, W; Ozato, K; Segars, J H

    1997-03-14

    Estrogen receptors regulate transcription of genes essential for sexual development and reproductive function. Since the retinoid X receptor (RXR) is able to modulate estrogen responsive genes and both 9-cis RA and fatty acids influenced development of estrogen responsive tumors, we hypothesized that estrogen responsive genes might be modulated by RXR and the fatty acid receptor (peroxisome proliferator-activated receptor, PPAR). To test this hypothesis, transfection assays in CV-1 cells were performed with an estrogen response element (ERE) coupled to a luciferase reporter construct. Addition of expression vectors for RXR and PPAR resulted in an 11-fold increase in luciferase activity in the presence of 9-cis RA. Furthermore, mobility shift assays demonstrated binding of RXR and PPAR to the vitellogenin A2-ERE and an ERE in the oxytocin promoter. Methylation interference assays demonstrated that specific guanine residues required for RXR/PPAR binding to the ERE were similar to residues required for ER binding. Moreover, RXR domain-deleted constructs in transfection assays showed that activation required RXR since an RXR delta AF-2 mutant completely abrogated reporter activity. Oligoprecipitation binding studies with biotinylated ERE and (35)S-labeled in vitro translated RXR constructs confirmed binding of delta AF-2 RXR mutant to the ERE in the presence of baculovirus-expressed PPAR. Finally, in situ hybridization confirmed RXR and PPAR mRNA expression in estrogen responsive tissues. Collectively, these data suggest that RXR and PPAR are present in reproductive tissues, are capable of activating estrogen responsive genes and suggest that the mechanism of activation may involve direct binding of the receptors to estrogen response elements.

  1. A link between FTO, ghrelin, and impaired brain food-cue responsivity

    Science.gov (United States)

    Karra, Efthimia; O’Daly, Owen G.; Choudhury, Agharul I.; Yousseif, Ahmed; Millership, Steven; Neary, Marianne T.; Scott, William R.; Chandarana, Keval; Manning, Sean; Hess, Martin E.; Iwakura, Hiroshi; Akamizu, Takashi; Millet, Queensta; Gelegen, Cigdem; Drew, Megan E.; Rahman, Sofia; Emmanuel, Julian J.; Williams, Steven C.R.; Rüther, Ulrich U.; Brüning, Jens C.; Withers, Dominic J.; Zelaya, Fernando O.; Batterham, Rachel L.

    2013-01-01

    Polymorphisms in the fat mass and obesity-associated gene (FTO) are associated with human obesity and obesity-prone behaviors, including increased food intake and a preference for energy-dense foods. FTO demethylates N6-methyladenosine, a potential regulatory RNA modification, but the mechanisms by which FTO predisposes humans to obesity remain unclear. In adiposity-matched, normal-weight humans, we showed that subjects homozygous for the FTO “obesity-risk” rs9939609 A allele have dysregulated circulating levels of the orexigenic hormone acyl-ghrelin and attenuated postprandial appetite reduction. Using functional MRI (fMRI) in normal-weight AA and TT humans, we found that the FTO genotype modulates the neural responses to food images in homeostatic and brain reward regions. Furthermore, AA and TT subjects exhibited divergent neural responsiveness to circulating acyl-ghrelin within brain regions that regulate appetite, reward processing, and incentive motivation. In cell models, FTO overexpression reduced ghrelin mRNA N6-methyladenosine methylation, concomitantly increasing ghrelin mRNA and peptide levels. Furthermore, peripheral blood cells from AA human subjects exhibited increased FTO mRNA, reduced ghrelin mRNA N6-methyladenosine methylation, and increased ghrelin mRNA abundance compared with TT subjects. Our findings show that FTO regulates ghrelin, a key mediator of ingestive behavior, and offer insight into how FTO obesity-risk alleles predispose to increased energy intake and obesity in humans. PMID:23867619

  2. A link between FTO, ghrelin, and impaired brain food-cue responsivity.

    Science.gov (United States)

    Karra, Efthimia; O'Daly, Owen G; Choudhury, Agharul I; Yousseif, Ahmed; Millership, Steven; Neary, Marianne T; Scott, William R; Chandarana, Keval; Manning, Sean; Hess, Martin E; Iwakura, Hiroshi; Akamizu, Takashi; Millet, Queensta; Gelegen, Cigdem; Drew, Megan E; Rahman, Sofia; Emmanuel, Julian J; Williams, Steven C R; Rüther, Ulrich U; Brüning, Jens C; Withers, Dominic J; Zelaya, Fernando O; Batterham, Rachel L

    2013-08-01

    Polymorphisms in the fat mass and obesity-associated gene (FTO) are associated with human obesity and obesity-prone behaviors, including increased food intake and a preference for energy-dense foods. FTO demethylates N6-methyladenosine, a potential regulatory RNA modification, but the mechanisms by which FTO predisposes humans to obesity remain unclear. In adiposity-matched, normal-weight humans, we showed that subjects homozygous for the FTO "obesity-risk" rs9939609 A allele have dysregulated circulating levels of the orexigenic hormone acyl-ghrelin and attenuated postprandial appetite reduction. Using functional MRI (fMRI) in normal-weight AA and TT humans, we found that the FTO genotype modulates the neural responses to food images in homeostatic and brain reward regions. Furthermore, AA and TT subjects exhibited divergent neural responsiveness to circulating acyl-ghrelin within brain regions that regulate appetite, reward processing, and incentive motivation. In cell models, FTO overexpression reduced ghrelin mRNA N6-methyladenosine methylation, concomitantly increasing ghrelin mRNA and peptide levels. Furthermore, peripheral blood cells from AA human subjects exhibited increased FTO mRNA, reduced ghrelin mRNA N6-methyladenosine methylation, and increased ghrelin mRNA abundance compared with TT subjects. Our findings show that FTO regulates ghrelin, a key mediator of ingestive behavior, and offer insight into how FTO obesity-risk alleles predispose to increased energy intake and obesity in humans.

  3. Ghrelin modulates the fMRI BOLD response of homeostatic and hedonic brain centers regulating energy balance in the rat.

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    Miklós Sárvári

    Full Text Available The orexigenic gut-brain peptide, ghrelin and its G-protein coupled receptor, the growth hormone secretagogue receptor 1a (GHS-R1A are pivotal regulators of hypothalamic feeding centers and reward processing neuronal circuits of the brain. These systems operate in a cooperative manner and receive a wide array of neuronal hormone/transmitter messages and metabolic signals. Functional magnetic resonance imaging was employed in the current study to map BOLD responses to ghrelin in different brain regions with special reference on homeostatic and hedonic regulatory centers of energy balance. Experimental groups involved male, ovariectomized female and ovariectomized estradiol-replaced rats. Putative modulation of ghrelin signaling by endocannabinoids was also studied. Ghrelin-evoked effects were calculated as mean of the BOLD responses 30 minutes after administration. In the male rat, ghrelin evoked a slowly decreasing BOLD response in all studied regions of interest (ROI within the limbic system. This effect was antagonized by pretreatment with GHS-R1A antagonist JMV2959. The comparison of ghrelin effects in the presence or absence of JMV2959 in individual ROIs revealed significant changes in the prefrontal cortex, nucleus accumbens of the telencephalon, and also within hypothalamic centers like the lateral hypothalamus, ventromedial nucleus, paraventricular nucleus and suprachiasmatic nucleus. In the female rat, the ghrelin effects were almost identical to those observed in males. Ovariectomy and chronic estradiol replacement had no effect on the BOLD response. Inhibition of the endocannabinoid signaling by rimonabant significantly attenuated the response of the nucleus accumbens and septum. In summary, ghrelin can modulate hypothalamic and mesolimbic structures controlling energy balance in both sexes. The endocannabinoid signaling system contributes to the manifestation of ghrelin's BOLD effect in a region specific manner. In females, the

  4. Behavioral meaningful opioidergic stimulation activates kappa receptor gene expression

    International Nuclear Information System (INIS)

    Teodorov, E.; Ferrari, M.F.R.; Fior-Chadi, D.R.; Camarini, R.; Felício, L.F.

    2012-01-01

    The periaqueductal gray (PAG) has been reported to be a location for opioid regulation of pain and a potential site for behavioral selection in females. Opioid-mediated behavioral and physiological responses differ according to the activity of opioid receptor subtypes. The present study investigated the effects of the peripheral injection of the kappa-opioid receptor agonist U69593 into the dorsal subcutaneous region of animals on maternal behavior and on Oprk1 gene activity in the PAG of female rats. Female Wistar rats weighing 200-250 g at the beginning of the study were randomly divided into 2 groups for maternal behavior and gene expression experiments. On day 5, pups were removed at 7:00 am and placed in another home cage that was distant from their mother. Thirty minutes after removing the pups, the dams were treated with U69593 (0.15 mg/kg, sc) or 0.9% saline (up to 1 mL/kg) and after 30 min were evaluated in the maternal behavior test. Latencies in seconds for pup retrieval, grouping, crouching, and full maternal behavior were scored. The results showed that U69593 administration inhibited maternal behavior (P < 0.05) because a lower percentage of U69593 group dams showed retrieval of first pup, retrieving all pups, grouping, crouching and displaying full maternal behavior compared to the saline group. Opioid gene expression was evaluated using real-time reverse-transcription polymerase chain reaction (RT-PCR). A single injection of U69593 increased Oprk1 PAG expression in both virgin (P < 0.05) and lactating female rats (P < 0.01), with no significant effect on Oprm1 or Oprd1 gene activity. Thus, the expression of kappa-opioid receptors in the PAG may be modulated by single opioid receptor stimulation and behavioral meaningful opioidergic transmission in the adult female might occur simultaneously to specific changes in gene expression of kappa-opioid receptor subtype. This is yet another alert for the complex role of the opioid system in female

  5. Behavioral meaningful opioidergic stimulation activates kappa receptor gene expression

    Energy Technology Data Exchange (ETDEWEB)

    Teodorov, E. [Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Paulo, SP (Brazil); Ferrari, M.F.R. [Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP (Brazil); Fior-Chadi, D.R. [Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP (Brazil); Camarini, R. [Departamento de Farmacologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP (Brazil); Felício, L.F. [Departamento de Patologia, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP (Brazil)

    2012-06-01

    The periaqueductal gray (PAG) has been reported to be a location for opioid regulation of pain and a potential site for behavioral selection in females. Opioid-mediated behavioral and physiological responses differ according to the activity of opioid receptor subtypes. The present study investigated the effects of the peripheral injection of the kappa-opioid receptor agonist U69593 into the dorsal subcutaneous region of animals on maternal behavior and on Oprk1 gene activity in the PAG of female rats. Female Wistar rats weighing 200-250 g at the beginning of the study were randomly divided into 2 groups for maternal behavior and gene expression experiments. On day 5, pups were removed at 7:00 am and placed in another home cage that was distant from their mother. Thirty minutes after removing the pups, the dams were treated with U69593 (0.15 mg/kg, sc) or 0.9% saline (up to 1 mL/kg) and after 30 min were evaluated in the maternal behavior test. Latencies in seconds for pup retrieval, grouping, crouching, and full maternal behavior were scored. The results showed that U69593 administration inhibited maternal behavior (P < 0.05) because a lower percentage of U69593 group dams showed retrieval of first pup, retrieving all pups, grouping, crouching and displaying full maternal behavior compared to the saline group. Opioid gene expression was evaluated using real-time reverse-transcription polymerase chain reaction (RT-PCR). A single injection of U69593 increased Oprk1 PAG expression in both virgin (P < 0.05) and lactating female rats (P < 0.01), with no significant effect on Oprm1 or Oprd1 gene activity. Thus, the expression of kappa-opioid receptors in the PAG may be modulated by single opioid receptor stimulation and behavioral meaningful opioidergic transmission in the adult female might occur simultaneously to specific changes in gene expression of kappa-opioid receptor subtype. This is yet another alert for the complex role of the opioid system in female

  6. Behavioral meaningful opioidergic stimulation activates kappa receptor gene expression

    Directory of Open Access Journals (Sweden)

    E. Teodorov

    2012-10-01

    Full Text Available The periaqueductal gray (PAG has been reported to be a location for opioid regulation of pain and a potential site for behavioral selection in females. Opioid-mediated behavioral and physiological responses differ according to the activity of opioid receptor subtypes. The present study investigated the effects of the peripheral injection of the kappa-opioid receptor agonist U69593 into the dorsal subcutaneous region of animals on maternal behavior and on Oprk1 gene activity in the PAG of female rats. Female Wistar rats weighing 200-250 g at the beginning of the study were randomly divided into 2 groups for maternal behavior and gene expression experiments. On day 5, pups were removed at 7:00 am and placed in another home cage that was distant from their mother. Thirty minutes after removing the pups, the dams were treated with U69593 (0.15 mg/kg, sc or 0.9% saline (up to 1 mL/kg and after 30 min were evaluated in the maternal behavior test. Latencies in seconds for pup retrieval, grouping, crouching, and full maternal behavior were scored. The results showed that U69593 administration inhibited maternal behavior (P < 0.05 because a lower percentage of kappa group dams showed retrieval of first pup, retrieving all pups, grouping, crouching and displaying full maternal behavior compared to the saline group. Opioid gene expression was evaluated using real-time reverse-transcription polymerase chain reaction (RT-PCR. A single injection of U69593 increased Oprk1 PAG expression in both virgin (P < 0.05 and lactating female rats (P < 0.01, with no significant effect on Oprm1 or Oprd1 gene activity. Thus, the expression of kappa-opioid receptors in the PAG may be modulated by single opioid receptor stimulation and behavioral meaningful opioidergic transmission in the adult female might occur simultaneously to specific changes in gene expression of kappa-opioid receptor subtype. This is yet another alert for the complex role of the opioid system in

  7. Development of ghrelin transgenic mice for elucidation of clinical implication of ghrelin.

    Science.gov (United States)

    Aotani, Daisuke; Ariyasu, Hiroyuki; Shimazu-Kuwahara, Satoko; Shimizu, Yoshiyuki; Nomura, Hidenari; Murofushi, Yoshiteru; Kaneko, Kentaro; Izumi, Ryota; Matsubara, Masaki; Kanda, Hajime; Noguchi, Michio; Tanaka, Tomohiro; Kusakabe, Toru; Miyazawa, Takashi; Nakao, Kazuwa

    2017-01-01

    To elucidate the clinical implication of ghrelin, we have been trying to generate variable models of transgenic (Tg) mice overexpressing ghrelin. We generated Tg mice overexpressing des-acyl ghrelin in a wide variety of tissues under the control of β-actin promoter. While plasma des-acyl ghrelin level in the Tg mice was 44-fold greater than that of control mice, there was no differences in the plasma ghrelin level between des-acyl ghrelin Tg and the control mice. The des-acyl ghrelin Tg mice exhibited the lower body weight and the shorter body length due to modulation of GH-IGF-1 axis. We tried to generate Tg mice expressing a ghrelin analog, which possessed ghrelin-like activity (Trp 3 -ghrelin Tg mice). The plasma Trp 3 -ghrelin concentration in Trp 3 -ghrelin Tg mice was approximately 85-fold higher than plasma ghrelin (acylated ghrelin) concentration seen in the control mice. Because Trp 3 -ghrelin is approximately 24-fold less potent than ghrelin, the plasma Trp 3 -ghrelin concentration in Trp 3 -ghrelin Tg mice was calculated to have approximately 3.5-fold biological activity greater than that of ghrelin (acylated ghrelin) in the control mice. Trp 3 -ghrelin Tg mice did not show any phenotypes except for reduced insulin sensitivity in 1-year old. After the identification of ghrelin O-acyltransferase (GOAT), we generated doubly Tg mice overexpressing both mouse des-acyl ghrelin and mouse GOAT in the liver by cross-mating the two kinds of Tg mice. The plasma ghrelin concentration of doubly Tg mice was approximately 2-fold higher than that of the control mice. No apparent phenotypic changes in body weight and food intake were observed in doubly Tg mice. Further studies are ongoing in our laboratory to generate Tg mice with the increased plasma ghrelin level to a greater extent. The better understanding of physiological and pathophysiological significance of ghrelin from experiments using an excellent animal model may provide a new therapeutic approach for human

  8. Antinociceptive Effect of Ghrelin in a Rat Model of Irritable Bowel Syndrome Involves TRPV1/Opioid Systems

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    Yuqing Mao

    2017-09-01

    Full Text Available Background/Aims: Irritable bowel syndrome (IBS, defined as recurrent abdominal pain and changes in bowel habits, seriously affects quality of life and ability to work. Ghrelin is a brain-gut hormone, which has been reported to show antinociceptive effects in peripheral pain. We investigated the effect of ghrelin on visceral hypersensitivity and pain in a rat model of IBS. Methods: Maternal deprivation (MD was used to provide a stress-induced model of IBS in Wistar rats. Colorectal distension (CRD was used to detect visceral sensitivity, which was evaluated by abdominal withdrawal reflex (AWR scores. Rats that were confirmed to have visceral hypersensitivity after MD were injected with ghrelin (10 µg/kg subcutaneously twice a week from weeks 7 to 8. [D-Lys3]-GHRP-6 (100 nmol/L and naloxone (100 nmol/L were administered subcutaneously to block growth hormone secretagogue receptor 1α (GHS-R1α and opioid receptors, respectively. Expression of transient receptor potential vanilloid type 1 (TRPV1 and µ and κ opioid receptors (MOR and KOR in colon, dorsal root ganglion (DRG and cerebral cortex tissues were detected by western blotting, quantitative real-time polymerase chain reaction (qRT-PCR, immunohistochemical analyses and immunofluorescence. Results: Ghrelin treatment increased expression of opioid receptors and inhibited expression of TRPV1 in colon, dorsal root ganglion (DRG and cerebral cortex. The antinociceptive effect of ghrelin in the rat model of IBS was partly blocked by both the ghrelin antagonist [D-Lys3]-GHRP-6 and the opioid receptor antagonist naloxone. Conclusion: The results indicate that ghrelin exerted an antinociceptive effect, which was mediated via TRPV1/opioid systems, in IBS-induced visceral hypersensitivity. Ghrelin might potentially be used as a new treatment for IBS.

  9. Glucocorticoid receptor gene polymorphism and juvenile idiopathic arthritis

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    Scheplyagina Larisa A

    2011-01-01

    Full Text Available Abstract Background The glucocorticoid receptor gene (NR3C1 has been suggested as a candidate gene affecting juvenile idiopathic arthritis (JIA course and prognosis. The purpose of this study is to investigate the glucocorticoid receptor gene BclI polymorphism (rs41423247 in JIA patients, the gene's role in susceptibility to juvenile idiopathic arthritis, and its associations with JIA activity, course and bone mineralization. Methods One hundred twenty-two Caucasian children with JIA and 143 healthy ethnically matched controls were studied. We checked markers of clinical and laboratory activity: morning stiffness, Ritchie Articular Index (RAI, swollen joint count (SJC, tender joint count (TJC, physician's visual analog scale (VAS, hemoglobin level (Hb, leukocyte count (L, platelet count (Pl, Westergren erythrocyte sedimentation rate (ESR, C-reactive protein (CRP, albumin, DAS and DAS28. Bone mineralization was measured by dual-energy X-ray absorptiometry (DXA of lumbar spine L1-L4. Assessments of bone metabolism included osteocalcin, C-terminal telopeptide (CTT, parathyroid hormone (PTH, total and ionized calcium, inorganic phosphate and total alkaline phosphatase (TAP. BclI polymorphism was genotyped by polymerase chain reaction restriction fragment length polymorphism. Results No association was observed between glucocorticoid receptor gene polymorphism and the presence or absence of JIA. In girls with JIA, the presence of the G allele was associated with an unfavorable arthritis course, a younger age of onset of arthritis (p = 0.0017, and higher inflammatory activity. The higher inflammatory activity was demonstrated by the following: increased time of morning stiffness (p = 0.02, VAS (p = 0.014, RAI (p = 0.048, DAS (p = 0.035, DAS28 (p = 0.05, Pl (p = 0.003, L (p = 0.046, CRP (p = 0.01. In addition, these patients had bone metabolism disturbances as follows: decreased BA (p = 0.0001, BMC (p = 0.00007, BMD (0.005 and Z score (p = 0.002; and

  10. Genetic association between ghrelin polymorphisms and Alzheimer's disease in a Japanese population.

    Science.gov (United States)

    Shibata, Nobuto; Ohnuma, Tohru; Kuerban, Bolati; Komatsu, Miwa; Arai, Heii

    2011-01-01

    Ghrelin has been reported to enter the hippocampus and to bind to the neurons of the hippocampal formation. This peptide also affects neuronal glucose uptake and decreases tau hyperphosphorylation. There is increasing evidence suggesting an association between ghrelin and Alzheimer's disease (AD) pathology. The aim of this study was to investigate whether single nucleotide polymorphisms (SNPs) of the ghrelin gene are associated with AD. The SNPs were genotyped using TaqMan technology and were analyzed using a case-control study design. Our case-control dataset consisted of 182 AD patients and 143 age-matched controls. Hardy-Weinberg equilibrium and linkage disequilibrium analyses suggest that the region in and around the gene is highly polymorphic. One SNP, rs4684677 (Leu90Gln), showed a marginal association with age of AD onset. We did not detect any association between the other SNPs of the ghrelin gene and AD. There have been few genetic studies on the relationship between circulating ghrelin and functional SNPs. Further multifactorial studies are needed to clarify the relationship between ghrelin and AD. Copyright © 2011 S. Karger AG, Basel.

  11. Dopamine Receptor Genes Modulate Associative Memory in Old Age.

    Science.gov (United States)

    Papenberg, Goran; Becker, Nina; Ferencz, Beata; Naveh-Benjamin, Moshe; Laukka, Erika J; Bäckman, Lars; Brehmer, Yvonne

    2017-02-01

    Previous research shows that associative memory declines more than item memory in aging. Although the underlying mechanisms of this selective impairment remain poorly understood, animal and human data suggest that dopaminergic modulation may be particularly relevant for associative binding. We investigated the influence of dopamine (DA) receptor genes on item and associative memory in a population-based sample of older adults (n = 525, aged 60 years), assessed with a face-scene item associative memory task. The effects of single-nucleotide polymorphisms of DA D1 (DRD1; rs4532), D2 (DRD2/ANKK1/Taq1A; rs1800497), and D3 (DRD3/Ser9Gly; rs6280) receptor genes were examined and combined into a single genetic score. Individuals carrying more beneficial alleles, presumably associated with higher DA receptor efficacy (DRD1 C allele; DRD2 A2 allele; DRD3 T allele), performed better on associative memory than persons with less beneficial genotypes. There were no effects of these genes on item memory or other cognitive measures, such as working memory, executive functioning, fluency, and perceptual speed, indicating a selective association between DA genes and associative memory. By contrast, genetic risk for Alzheimer disease (AD) was associated with worse item and associative memory, indicating adverse effects of APOE ε4 and a genetic risk score for AD (PICALM, BIN1, CLU) on episodic memory in general. Taken together, our results suggest that DA may be particularly important for associative memory, whereas AD-related genetic variations may influence overall episodic memory in older adults without dementia.

  12. Ghrelin at the interface of obesity and reward.

    Science.gov (United States)

    Schellekens, Harriët; Dinan, Timothy G; Cryan, John F

    2013-01-01

    The prevalence of obesity continues to increase and has reached epidemic proportions. Accumulating data over the past few decades have given us key insights and broadened our understanding of the peripheral and central regulation of energy homeostasis. Despite this, the currently available pharmacological treatments, reducing body weight, remain limited due to poor efficacy and side effects. The gastric peptide ghrelin has been identified as the only orexigenic hormone from the periphery to act in the hypothalamus to stimulate food intake. Recently, a role for ghrelin and its receptor at the interface between homeostatic control of appetite and reward circuitries modulating the hedonic aspects of food has also emerged. Nonhomeostatic factors such as the rewarding and motivational value of food, which increase with food palatability and caloric content, can override homeostatic control of food intake. This nonhomeostatic decision to eat leads to overconsumption beyond nutritional needs and is being recognized as a key component in the underlying causes for the increase in obesity incidence worldwide. In addition, the hedonic feeding behavior has been linked to food addiction and an important role for ghrelin in the development of addiction has been suggested. Moreover, plasma ghrelin levels are responsive to conditions of stress, and recent evidence has implicated ghrelin in stress-induced food-reward behavior. The prominent role of the ghrelinergic system in the regulation of feeding gives rise to it as an effective target for the development of successful antiobesity pharmacotherapies that not only affect satiety but also selectively modulate the rewarding properties of food and reduce the desire to eat. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Human estrogen receptor (ESR) gene locus: PssI dimorphism

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, R T; Taylor, J E; Frossard, P M [California Biotechnology Inc., Mountain View, CA (USA); Shine, J J [Garvan Institute, Darlinghurst (Australia)

    1988-07-25

    pESR-2, a 2.1 kb partial cDNA containing the entire translated sequence of the human estrogen receptor mRNA isolated from MCF-7 human breast cancer cells, was subcloned in the Eco RI site of pBR322. PssI (PuGGNCCPy) identifies a single two-allele polymorphism with bands at either 1.7 or 1.4 kb, as well as invariant bands at 12.6, 9.3, 4.1, 3.7, 2.4, 2.2, and 1.2 kb. Its frequency was studied in 77 unrelated North American Caucasians. The human estrogen receptor gene has been localized to 6q24 -- q27 by in situ hybridization. Co-dominant segregation is demonstrated in one family (8 individuals).

  14. Ghrelin treatment causes increased food intake and retention of lean body mass in a rat model of cancer cachexia.

    Science.gov (United States)

    DeBoer, Mark D; Zhu, Xin Xia; Levasseur, Peter; Meguid, Michael M; Suzuki, Susumu; Inui, Akio; Taylor, John E; Halem, Heather A; Dong, Jesse Z; Datta, Rakesh; Culler, Michael D; Marks, Daniel L

    2007-06-01

    Cancer cachexia is a debilitating syndrome of anorexia and loss of lean body mass that accompanies many malignancies. Ghrelin is an orexigenic hormone with a short half-life that has been shown to improve food intake and weight gain in human and animal subjects with cancer cachexia. We used a rat model of cancer cachexia and administered human ghrelin and a synthetic ghrelin analog BIM-28131 via continuous infusion using sc osmotic minipumps. Tumor-implanted rats receiving human ghrelin or BIM-28131 exhibited a significant increase in food consumption and weight gain vs. saline-treated animals. We used dual-energy x-ray absorptiometry scans to show that the increased weight was due to maintenance of lean mass vs. a loss of lean mass in saline-treated animals. Also, BIM-28131 significantly limited the loss of fat mass normally observed in tumor-implanted rats. We further performed real-time PCR analysis of the hypothalami and brainstems and found that ghrelin-treated animals exhibited a significant increase in expression of orexigenic peptides agouti-related peptide and neuropeptide Y in the hypothalamus and a significant decrease in the expression of IL-1 receptor-I transcript in the hypothalamus and brainstem. We conclude that ghrelin and a synthetic ghrelin receptor agonist improve weight gain and lean body mass retention via effects involving orexigenic neuropeptides and antiinflammatory changes.

  15. Integrating Solid-State NMR and Computational Modeling to Investigate the Structure and Dynamics of Membrane-Associated Ghrelin

    Science.gov (United States)

    Els-Heindl, Sylvia; Chollet, Constance; Scheidt, Holger A.; Beck-Sickinger, Annette G.; Meiler, Jens; Huster, Daniel

    2015-01-01

    The peptide hormone ghrelin activates the growth hormone secretagogue receptor 1a, also known as the ghrelin receptor. This 28-residue peptide is acylated at Ser3 and is the only peptide hormone in the human body that is lipid-modified by an octanoyl group. Little is known about the structure and dynamics of membrane-associated ghrelin. We carried out solid-state NMR studies of ghrelin in lipid vesicles, followed by computational modeling of the peptide using Rosetta. Isotropic chemical shift data of isotopically labeled ghrelin provide information about the peptide’s secondary structure. Spin diffusion experiments indicate that ghrelin binds to membranes via its lipidated Ser3. Further, Phe4, as well as electrostatics involving the peptide’s positively charged residues and lipid polar headgroups, contribute to the binding energy. Other than the lipid anchor, ghrelin is highly flexible and mobile at the membrane surface. This observation is supported by our predicted model ensemble, which is in good agreement with experimentally determined chemical shifts. In the final ensemble of models, residues 8–17 form an α-helix, while residues 21–23 and 26–27 often adopt a polyproline II helical conformation. These helices appear to assist the peptide in forming an amphipathic conformation so that it can bind to the membrane. PMID:25803439

  16. Integrating solid-state NMR and computational modeling to investigate the structure and dynamics of membrane-associated ghrelin.

    Directory of Open Access Journals (Sweden)

    Gerrit Vortmeier

    Full Text Available The peptide hormone ghrelin activates the growth hormone secretagogue receptor 1a, also known as the ghrelin receptor. This 28-residue peptide is acylated at Ser3 and is the only peptide hormone in the human body that is lipid-modified by an octanoyl group. Little is known about the structure and dynamics of membrane-associated ghrelin. We carried out solid-state NMR studies of ghrelin in lipid vesicles, followed by computational modeling of the peptide using Rosetta. Isotropic chemical shift data of isotopically labeled ghrelin provide information about the peptide's secondary structure. Spin diffusion experiments indicate that ghrelin binds to membranes via its lipidated Ser3. Further, Phe4, as well as electrostatics involving the peptide's positively charged residues and lipid polar headgroups, contribute to the binding energy. Other than the lipid anchor, ghrelin is highly flexible and mobile at the membrane surface. This observation is supported by our predicted model ensemble, which is in good agreement with experimentally determined chemical shifts. In the final ensemble of models, residues 8-17 form an α-helix, while residues 21-23 and 26-27 often adopt a polyproline II helical conformation. These helices appear to assist the peptide in forming an amphipathic conformation so that it can bind to the membrane.

  17. Diverse growth hormone receptor gene mutations in Laron syndrome.

    Science.gov (United States)

    Berg, M A; Argente, J; Chernausek, S; Gracia, R; Guevara-Aguirre, J; Hopp, M; Pérez-Jurado, L; Rosenbloom, A; Toledo, S P; Francke, U

    1993-01-01

    To better understand the molecular genetic basis and genetic epidemiology of Laron syndrome (growth-hormone insensitivity syndrome), we analyzed the growth-hormone receptor (GHR) genes of seven unrelated affected individuals from the United States, South America, Europe, and Africa. We amplified all nine GHR gene exons and splice junctions from these individuals by PCR and screened the products for mutations by using denaturing gradient gel electrophoresis (DGGE). We identified a single GHR gene fragment with abnormal DGGE results for each affected individual, sequenced this fragment, and, in each case, identified a mutation likely to cause Laron syndrome, including two nonsense mutations (R43X and R217X), two splice-junction mutations, (189-1 G to T and 71 + 1 G to A), and two frameshift mutations (46 del TT and 230 del TA or AT). Only one of these mutations, R43X, has been previously reported. Using haplotype analysis, we determined that this mutation, which involves a CpG dinucleotide hot spot, likely arose as a separate event in this case, relative to the two prior reports of R43X. Aside from R43X, the mutations we identified are unique to patients from particular geographic regions. Ten GHR gene mutations have now been described in this disorder. We conclude that Laron syndrome is caused by diverse GHR gene mutations, including deletions, RNA processing defects, translational stop codons, and missense codons. All the identified mutations involve the extracellular domain of the receptor, and most are unique to particular families or geographic areas. Images Figure 1 Figure 2 PMID:8488849

  18. Intracellular insulin-receptor dissociation and segregation in a rat fibroblast cell line transfected with a human insulin receptor gene

    International Nuclear Information System (INIS)

    Levy, J.R.; Olefsky, J.M.

    1988-01-01

    The cellular processing of insulin and insulin receptors was studied using a rat fibroblast cell line that had been transfected with a normal human insulin receptor gene, expressing approximately 500 times the normal number of native fibroblasts insulin receptors. These cells bind and internalize insulin normally. Biochemically assays based on the selective precipitation by polyethylene glycol of intact insulin-receptor complexes but not of free intracellular insulin were developed to study the time course of intracellular insulin-receptor dissociation. Fibroblasts were incubated with radiolabeled insulin at 4 0 C, and internalization of insulin-receptor complexes was initiated by warming the cells to 37 0 C. Within 2 min, 90% of the internalized radioactivity was composed of intact insulin-receptor complexes. The dissociation of insulin from internalized insulin-receptor complexes was markedly inhibited by monensin and chloroquine. Furthermore, chloroquine markedly increased the number of cross-linkable intracellular insulin-receptor complexes, as analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis autoradiography. These findings suggest that acidification of intracellular vesicles is responsible for insulin-receptor dissociation. Physical segregation of dissociated intracellular insulin from its receptor was monitored. The results are consistent with the view that segregation of insulin and receptor occurs 5-10 min after initiation of dissociation. These studies demonstrate the intracellular itinerary of insulin-receptor complexes, including internalization, dissociation of insulin from the internalized receptor within an acidified compartment, segregation of insulin from the receptor, and subsequent ligand degradation

  19. Genomic organization, annotation, and ligand-receptor inferences of chicken chemokines and chemokine receptor genes based on comparative genomics

    Directory of Open Access Journals (Sweden)

    Sze Sing-Hoi

    2005-03-01

    Full Text Available Abstract Background Chemokines and their receptors play important roles in host defense, organogenesis, hematopoiesis, and neuronal communication. Forty-two chemokines and 19 cognate receptors have been found in the human genome. Prior to this report, only 11 chicken chemokines and 7 receptors had been reported. The objectives of this study were to systematically identify chicken chemokines and their cognate receptor genes in the chicken genome and to annotate these genes and ligand-receptor binding by a comparative genomics approach. Results Twenty-three chemokine and 14 chemokine receptor genes were identified in the chicken genome. All of the chicken chemokines contained a conserved CC, CXC, CX3C, or XC motif, whereas all the chemokine receptors had seven conserved transmembrane helices, four extracellular domains with a conserved cysteine, and a conserved DRYLAIV sequence in the second intracellular domain. The number of coding exons in these genes and the syntenies are highly conserved between human, mouse, and chicken although the amino acid sequence homologies are generally low between mammalian and chicken chemokines. Chicken genes were named with the systematic nomenclature used in humans and mice based on phylogeny, synteny, and sequence homology. Conclusion The independent nomenclature of chicken chemokines and chemokine receptors suggests that the chicken may have ligand-receptor pairings similar to mammals. All identified chicken chemokines and their cognate receptors were identified in the chicken genome except CCR9, whose ligand was not identified in this study. The organization of these genes suggests that there were a substantial number of these genes present before divergence between aves and mammals and more gene duplications of CC, CXC, CCR, and CXCR subfamilies in mammals than in aves after the divergence.

  20. Ghrelin enhances cue-induced bar pressing for high fat food.

    Science.gov (United States)

    St-Onge, Veronique; Watts, Alexander; Abizaid, Alfonso

    2016-02-01

    Ghrelin is an orexigenic hormone produced by the stomach that acts on growth hormone secretagogue receptors (GHSRs) both peripherally and centrally. The presence of GHSRs in the ventral tegmental area (VTA) suggests that ghrelin signaling at this level may increase the incentive value of palatable foods as well as other natural and artificial rewards. The present investigation sought to determine if ghrelin plays a role in relapse to such foods following a period of abstinence. To achieve this, thirty-six male Long Evans rats were trained to press a lever to obtain a high fat chocolate food reward on a fixed ratio schedule of 1. Following an extinction period during which lever presses were not reinforced, rats were implanted with a cannula connected to a minipump that continuously delivered ghrelin, a GHSR antagonist ([d-Lys-3]-GHRP-6), or saline in the VTA for 14days. One week later, food reward-associated cues, food reward priming, and an overnight fast were used to induce reinstatement of the lever pressing response. Our results indicate that intra-VTA ghrelin enhances cue-induced reinstatement of responses for palatable food pellets. To the extent that the reinstatement paradigm is considered a valid model of relapse in humans, this suggests that ghrelin signaling facilitates relapse to preferred foods in response to food cues through GHSR signaling in the VTA. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Ghrelin Attenuates Retinal Neuronal Autophagy and Apoptosis in an Experimental Rat Glaucoma Model.

    Science.gov (United States)

    Zhu, Ke; Zhang, Meng-Lu; Liu, Shu-Ting; Li, Xue-Yan; Zhong, Shu-Min; Li, Fang; Xu, Ge-Zhi; Wang, Zhongfeng; Miao, Yanying

    2017-12-01

    Ghrelin, a natural ligand for the growth hormone secretagogue receptor type 1a (GHSR-1a), may protect retinal neurons against glaucomatous injury. We therefore characterized the underlying mechanism of the ghrelin/GHSR-1a-mediated neuroprotection with a rat chronic intraocular hypertension (COH) model. The rat COH model was produced by blocking episcleral veins. A combination of immunohistochemistry, Western blot, TUNEL assay, and retrograde labeling of retinal ganglion cells (RGCs) was used. Elevation of intraocular pressure induced a significant increase in ghrelin and GHSR-1a expression in retinal cells, including RGCs and Müller cells. Western blot confirmed that the protein levels of ghrelin exhibited a transient upregulation at week 2 after surgery (G2w), while the GHSR-1a protein levels were maintained at high levels from G2w to G4w. In COH retinas, the ratio of LC3-II/LC-I and beclin1, two autophagy-related proteins, were increased from G1w to G4w, and the cleavage product of caspase3, an apoptotic executioner, was detected from G2w to G4w. Intraperitoneal injection of ghrelin significantly increased the number of surviving RGCs; inhibited the changes of LC3-II/LC-I, beclin1, and the cleavage products of caspase3; and reduced the number of TUNEL-positive cells in COH retinas. Ghrelin treatment also reversed the decreased levels of p-Akt and p-mTOR, upregulated GHSR-1a protein levels, and attenuated glial fibrillary acidic protein levels in COH retinas. All these results suggest that ghrelin may provide neuroprotective effect in COH retinas through activating ghrelin/GHSR-1a system, which was mediated by inhibiting retinal autophagy, ganglion cell apoptosis, and Müller cell gliosis.

  2. Ghrelin did not change coronary angiogenesis in diet-induced obese mice.

    Science.gov (United States)

    Khazaei, M; Tahergorabi, Z

    2017-02-28

    Ghrelin is a 28 amino acids peptide that initially was recognized as an endogenous ligand for growth hormone secretagogue receptor (GHSR). Recently, a number of studies demonstrated that ghrelin is a cardiovascular hormone with a series cardiovascular effect. The main objective of this study was to investigate the effect of systemic ghrelin administration on angiogenesis in the heart and its correlation with serum leptin levels in normal and diet-induced obese mice. 24 male C57BL/6 mice were randomly divided into four groups: normal diet (ND) or control, ND+ghrelin, high-fat-diet (HFD) or obese and HFD+ghrelin (n=6/group). Obese and control groups received HFD or ND, respectively, for 14 weeks. Then, the ghrelin was injected subcutaneously 100µg/kg twice daily. After 10 days, the animals were sacrificed, blood samples were taken and the hearts were removed. The angiogenic response in the heart was assessed by immunohisochemical staining. HFD significantly increased angiogenesis in the heart expressed as the number of CD31 positive cells than standard diet. Ghrelin did not alter angiogenesis in the heart in both obese and control groups, however, it reduced serum nitric oxide (NO) and leptin levels in obese mice. There was a strong positive correlation between the number of CD31 positive cells and serum leptin concentration (r=0.74). Leptin as an angiogenic factor has a positive correlation with angiogenesis in the heart. Although systemic administration of ghrelin reduced serum leptin and NO levels in obese mice, however, it could not alter coronary angiogenesis.

  3. Clone and expression of human transferrin receptor gene: a marker gene for magnetic resonance imaging

    International Nuclear Information System (INIS)

    Li Li; Liu Lizhi; Lv Yanchun; Liu Xuewen; Cui Chunyan; Wu Peihong; Liu Qicai; Ou Shanxing

    2007-01-01

    Objective: To clone human transferrin receptor (hTfR) gene and construct expression vector producing recombination protein. Methods: Human transferrin receptor gene cDNA was amplified by RT-PCR from human embryonic liver and lung tissue. Recombinant pcDNA3-hTfR and pEGFP-Cl-hTfR plasmids were constructed and confirmed by DNA sequencing. These plasmids were stably transfected into the HEK293 cells. The protein expression in vitro was confirmed by Western Blot. The efficiency of expression and the location of hTfR were also investigated by fluorescence microscopy and confocal fluorescence microscopy. Results: The full length cDNA of hTfR gene (2332 bp) was cloned and sequenced. The hTfR (190 000) was overexpressed in transfected HEK293 cells by Western blot analysis. Fluorescence micrographs displayed that the hTfR was expressed at high level and located predominantly in the cell surface. Conclusions: Human transferrin receptor (hTfR) gene has been successfully cloned and obtained high-level expression in HEK293 cells, and the recombination protein of hTfR distributed predominantly in the cell membrane. (authors)

  4. Neuroprotective actions of ghrelin and growth hormone secretagogues

    Directory of Open Access Journals (Sweden)

    Laura M. Frago

    2011-09-01

    Full Text Available The brain incorporates and coordinates information based on the hormonal environment, receiving information from peripheral tissues through the circulation. Although it was initially thought that hormones only acted on the hypothalamus to perform endocrine functions, it is now known that they in fact exert diverse actions on many different brain regions including the hypothalamus. Ghrelin is a gastric hormone that stimulates growth hormone (GH secretion and food intake to regulate energy homeostasis and body weight by binding to its receptor, GHS-R1a, which is most highly expressed in the pituitary and hypothalamus. In addition, ghrelin has effects on learning and memory, reward and motivation, anxiety and depression, and could be a potential therapeutic agent in neurodegenerative disorders where excitotoxic neuronal cell death and inflammatory processes are involved.

  5. Oxytocin receptor gene variation predicts subjective responses to MDMA.

    Science.gov (United States)

    Bershad, Anya K; Weafer, Jessica J; Kirkpatrick, Matthew G; Wardle, Margaret C; Miller, Melissa A; de Wit, Harriet

    2016-12-01

    3,4-Methylenedioxymethamphetamine (MDMA, "ecstasy") enhances desire to socialize and feelings of empathy, which are thought to be related to increased oxytocin levels. Thus, variation in the oxytocin receptor gene (OXTR) may influence responses to the drug. Here, we examined the influence of a single OXTR nucleotide polymorphism (SNP) on responses to MDMA in humans. Based on findings that carriers of the A allele at rs53576 exhibit reduced sensitivity to oxytocin-induced social behavior, we hypothesized that these individuals would show reduced subjective responses to MDMA, including sociability. In this three-session, double blind, within-subjects study, healthy volunteers with past MDMA experience (N = 68) received a MDMA (0, 0.75 mg/kg, and 1.5 mg/kg) and provided self-report ratings of sociability, anxiety, and drug effects. These responses were examined in relation to rs53576. MDMA (1.5 mg/kg) did not increase sociability in individuals with the A/A genotype as it did in G allele carriers. The genotypic groups did not differ in responses at the lower MDMA dose, or in cardiovascular or other subjective responses. These findings are consistent with the idea that MDMA-induced sociability is mediated by oxytocin, and that variation in the oxytocin receptor gene may influence responses to the drug.

  6. Control of Transcriptional Repression of the Vitellogenin Receptor Gene in Largemouth Bass (Micropterus Salmoides) by Select Estrogen Receptors Isotypes

    OpenAIRE

    Dominguez, Gustavo A.; Bisesi, Joseph H.; Kroll, Kevin J.; Denslow, Nancy D.; Sabo-Attwood, Tara

    2014-01-01

    The vitellogenin receptor (Vtgr) plays an important role in fish reproduction. This receptor functions to incorporate vitellogenin (Vtg), a macromolecule synthesized and released from the liver in the bloodstream, into oocytes where it is processed into yolk. Although studies have focused on the functional role of Vtgr in fish, the mechanistic control of this gene is still unexplored. Here we report the identification and analysis of the first piscine 5′ regulatory region of the vtgr gene whi...

  7. AT1 Receptor Gene Polymorphisms in relation to Postprandial Lipemia

    Directory of Open Access Journals (Sweden)

    B. Klop

    2012-01-01

    Full Text Available Background. Recent data suggest that the renin-angiotensin system may be involved in triglyceride (TG metabolism. We explored the effect of the common A1166C and C573T polymorphisms of the angiotensin II type 1 receptor (AT1R gene on postprandial lipemia. Methods. Eighty-two subjects measured daytime capillary TG, and postprandial lipemia was estimated as incremental area under the TG curve. The C573T and A1166C polymorphisms of the AT1R gene were determined. Results. Postprandial lipemia was significantly higher in homozygous carriers of the 1166-C allele (9.39±8.36 mM*h/L compared to homozygous carriers of the 1166-A allele (2.02±6.20 mM*h/L (P<0.05. Postprandial lipemia was similar for the different C573T polymorphisms. Conclusion. The 1166-C allele of the AT1R gene seems to be associated with increased postprandial lipemia. These data confirm the earlier described relationships between the renin-angiotensin axis and triglyceride metabolism.

  8. Ghrelin- and GH-induced insulin resistance

    DEFF Research Database (Denmark)

    Vestergaard, Esben Thyssen; Krag, Morten B; Poulsen, Morten M

    2013-01-01

    Supraphysiological levels of ghrelin and GH induce insulin resistance. Serum levels of retinol-binding protein-4 (RBP4) correlate inversely with insulin sensitivity in patients with type 2 diabetes. We aimed to determine whether ghrelin and GH affect RBP4 levels in human subjects.......Supraphysiological levels of ghrelin and GH induce insulin resistance. Serum levels of retinol-binding protein-4 (RBP4) correlate inversely with insulin sensitivity in patients with type 2 diabetes. We aimed to determine whether ghrelin and GH affect RBP4 levels in human subjects....

  9. The Human Experience With Ghrelin Administration

    Science.gov (United States)

    Garin, Margaret C.; Burns, Carrie M.; Kaul, Shailja

    2013-01-01

    Context: Ghrelin is an endogenous stimulator of GH and is implicated in a number of physiological processes. Clinical trials have been performed in a variety of patient populations, but there is no comprehensive review of the beneficial and adverse consequences of ghrelin administration to humans. Evidence Acquisition: PubMed was utilized, and the reference list of each article was screened. We included 121 published articles in which ghrelin was administered to humans. Evidence Synthesis: Ghrelin has been administered as an infusion or a bolus in a variety of doses to 1850 study participants, including healthy participants and patients with obesity, prior gastrectomy, cancer, pituitary disease, diabetes mellitus, eating disorders, and other conditions. There is strong evidence that ghrelin stimulates appetite and increases circulating GH, ACTH, cortisol, prolactin, and glucose across varied patient populations. There is a paucity of evidence regarding the effects of ghrelin on LH, FSH, TSH, insulin, lipolysis, body composition, cardiac function, pulmonary function, the vasculature, and sleep. Adverse effects occurred in 20% of participants, with a predominance of flushing and gastric rumbles and a mild degree of severity. The few serious adverse events occurred in patients with advanced illness and were not clearly attributable to ghrelin. Route of administration may affect the pattern of adverse effects. Conclusions: Existing literature supports the short-term safety of ghrelin administration and its efficacy as an appetite stimulant in diverse patient populations. There is some evidence to suggest that ghrelin has wider ranging therapeutic effects, although these areas require further investigation. PMID:23533240

  10. Ghrelin and obestatin levels in rheumatoid arthritis.

    Science.gov (United States)

    Koca, Suleyman Serdar; Ozgen, Metin; Aydin, Suleyman; Dag, Sait; Evren, Bahri; Isik, Ahmet

    2008-10-01

    Ghrelin is a powerful, endogenous orexigenic peptide. In addition, ghrelin has anti-inflammatory effects, and it has been reported that ghrelin down-regulates pro-inflammatory cytokines, including interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha. Obestatin appears to decrease food intake and appetite, and its potential role in inflammation is not yet clear. The aims of this study were to assess total and acylated (active) ghrelin and obestatin serum levels and their relations with inflammatory status in rheumatoid arthritis (RA) patients. Fasting blood samples were obtained from 37 patients with RA, 29 patients with Behçet's disease (BD) and 28 healthy controls (HC). Total ghrelin and obestatin levels were measured by radioimmunoassay and acylated ghrelin was quantified by enzyme-linked immunosorbent assay. Patients with RA had lower total ghrelin, but higher obestatin levels than patients with BD (pghrelin. Total ghrelin level was not correlated with any study parameters in the all groups. Obestatin level correlated with erythrocyte sedimentation rate and DAS-28 in the RA group, the level of IL-6 in the BD group, and with the level of TNF-alpha in the HC group (r=0.400, pghrelin and clinical or laboratory markers of disease activity in RA. Surprisingly, obestatin correlated with some inflammatory markers. So, obestatin seems to be more valuable than ghrelin in the pathogenesis of RA.

  11. A Gene Implicated in Activation of Retinoic Acid Receptor Targets Is a Novel Renal Agenesis Gene in Humans

    DEFF Research Database (Denmark)

    Brophy, Patrick D.; Rasmussen, Maria; Parida, Mrutyunjaya

    2017-01-01

    investigations have identified several gene variants that cause RA, including EYA1, LHX1, and WT1 However, whereas compound null mutations of genes encoding α and γ retinoic acid receptors (RARs) cause RA in mice, to date there have been no reports of variants in RAR genes causing RA in humans. In this study, we...... in humans....

  12. The Dopamine D2 Receptor Gene, Perceived Parental Support, and Adolescent Loneliness: Longitudinal Evidence for Gene-Environment Interactions

    Science.gov (United States)

    van Roekel, Eeske; Goossens, Luc; Scholte, Ron H. J.; Engels, Rutger C. M. E.; Verhagen, Maaike

    2011-01-01

    Background: Loneliness is a common problem in adolescence. Earlier research focused on genes within the serotonin and oxytocin systems, but no studies have examined the role of dopamine-related genes in loneliness. In the present study, we focused on the dopamine D2 receptor gene (DRD2). Methods: Associations among the DRD2, sex, parental support,…

  13. The dopamine D2 receptor gene, perceived parental support, and adolescent loneliness : longitudinal evidence for gene-environment interactions

    NARCIS (Netherlands)

    van Roekel, Eeske; Goossens, Luc; Scholte, Ron H. J.; Engels, Rutger C. M. E.; Verhagen, Maaike

    2011-01-01

    Background: Loneliness is a common problem in adolescence. Earlier research focused on genes within the serotonin and oxytocin systems, but no studies have examined the role of dopamine-related genes in loneliness. In the present study, we focused on the dopamine D2 receptor gene (DRD2). Methods:

  14. Liver X Receptor Genes Variants Modulate ALS Phenotype.

    Science.gov (United States)

    Mouzat, Kevin; Molinari, Nicolas; Kantar, Jovana; Polge, Anne; Corcia, Philippe; Couratier, Philippe; Clavelou, Pierre; Juntas-Morales, Raul; Pageot, Nicolas; Lobaccaro, Jean -Marc A; Raoul, Cedric; Lumbroso, Serge; Camu, William

    2018-03-01

    Amyotrophic lateral sclerosis (ALS) is one of the most severe motor neuron (MN) disorders in adults. Phenotype of ALS patients is highly variable and may be influenced by modulators of energy metabolism. Recent works have implicated the liver X receptors α and β (LXRs), either in the propagation process of ALS or in the maintenance of MN survival. LXRs are nuclear receptors activated by oxysterols, modulating cholesterol levels, a suspected modulator of ALS severity. In a cohort of 438 ALS patients and 330 healthy controls, the influence of LXR genes on ALS risk and phenotype was studied using single nucleotide polymorphisms (SNPs). The two LXRα SNPs rs2279238 and rs7120118 were shown to be associated with age at onset in ALS patients. Consistently, homozygotes were twice more correlated than were heterozygotes to delayed onset. The onset was thus delayed by 3.9 years for rs2279238 C/T carriers and 7.8 years for T/T carriers. Similar results were obtained for rs7120118 (+2.1 years and +6.7 years for T/C and C/C genotypes, respectively). The LXRβ SNP rs2695121 was also shown to be associated with a 30% increase of ALS duration (p = 0.0055, FDR = 0.044). The tested genotypes were not associated with ALS risk. These findings add further evidence to the suspected implication of LXR genes in the disease process of ALS and might open new perspectives in ALS therapeutics.

  15. Context dependent regulatory patterns of the androgen receptor and androgen receptor target genes

    International Nuclear Information System (INIS)

    Olsen, Jan Roger; Azeem, Waqas; Hellem, Margrete Reime; Marvyin, Kristo; Hua, Yaping; Qu, Yi; Li, Lisha; Lin, Biaoyang; Ke, XI- Song; Øyan, Anne Margrete; Kalland, Karl- Henning

    2016-01-01

    Expression of the androgen receptor (AR) is associated with androgen-dependent proliferation arrest and terminal differentiation of normal prostate epithelial cells. Additionally, activation of the AR is required for survival of benign luminal epithelial cells and primary cancer cells, thus androgen deprivation therapy (ADT) leads to apoptosis in both benign and cancerous tissue. Escape from ADT is known as castration-resistant prostate cancer (CRPC). In the course of CRPC development the AR typically switches from being a cell-intrinsic inhibitor of normal prostate epithelial cell proliferation to becoming an oncogene that is critical for prostate cancer cell proliferation. A clearer understanding of the context dependent activation of the AR and its target genes is therefore desirable. Immortalized human prostate basal epithelial EP156T cells and progeny cells that underwent epithelial to mesenchymal transition (EMT), primary prostate epithelial cells (PrECs) and prostate cancer cell lines LNCaP, VCaP and 22Rv1 were used to examine context dependent restriction and activation of the AR and classical target genes, such as KLK3. Genome-wide gene expression analyses and single cell protein analyses were applied to study the effect of different contexts. A variety of growth conditions were tested and found unable to activate AR expression and transcription of classical androgen-dependent AR target genes, such as KLK3, in prostate epithelial cells with basal cell features or in mesenchymal type prostate cells. The restriction of androgen- and AR-dependent transcription of classical target genes in prostate basal epithelial cells was at the level of AR expression. Exogenous AR expression was sufficient for androgen-dependent transcription of AR target genes in prostate basal epithelial cells, but did not exert a positive feedback on endogenous AR expression. Treatment of basal prostate epithelial cells with inhibitors of epigenetic gene silencing was not efficient in

  16. Identifying polymorphisms in the Rattus norvegicus D3 dopamine receptor gene and regulatory region

    NARCIS (Netherlands)

    Smits, B.M.; D'Souza, U.M.; Berezikov, E.; Cuppen, E.; Sluyter, F.

    2004-01-01

    The D(3) dopamine receptor has been implicated in several neuropsychiatric disorders, including schizophrenia, Parkinson's disease and addiction. Sequence variation in the D(3) gene can lead to subtle alteration in receptor structure or gene expression and thus to a different phenotype. In this

  17. Ghrelin and food reward: the story of potential underlying substrates.

    Science.gov (United States)

    Skibicka, Karolina P; Dickson, Suzanne L

    2011-11-01

    The incidence of obesity is increasing at an alarming rate and this worldwide epidemic represents a significant decrease in life span and quality of life of a large part of the affected population. Therefore an understanding of mechanisms underlying food overconsumption and obesity development is urgent and essential to find potential treatments. Research investigating mechanisms underlying obesity and the control of food intake has recently experienced a major shift in focus, from the brain's hypothalamus to additional important neural circuits controlling emotion, cognition and motivated behavior. Among them, the mesolimbic system, and the changes in reward and motivated behavior for food, emerge as new promising treatment targets. Furthermore, there is also growing appreciation of the impact of peripheral hormones that signal nutrition status to the mesolimbic areas, and especially the only known circulating orexigenic hormone, ghrelin. This review article provides a synthesis of recent evidence concerning the impact of manipulation of ghrelin and its receptor on models of food reward/food motivation behavior and the mesolimbic circuitry. Particular attention is given to the potential neurocircuitry and neurotransmitter systems downstream of ghrelin's effects on food reward. Copyright © 2011. Published by Elsevier Inc.

  18. Effects of Ghrelin miRNA on Inflammation and Calcium Pathway in Pancreatic Acinar Cells of Acute Pancreatitis.

    Science.gov (United States)

    Tang, Xiping; Tang, Guodu; Liang, Zhihai; Qin, Mengbin; Fang, Chunyun; Zhang, Luyi

    The study investigated the effects of endogenous targeted inhibition of ghrelin gene on inflammation and calcium pathway in an in vitro pancreatic acinar cell model of acute pancreatitis. Lentiviral expression vector against ghrelin gene was constructed and transfected into AR42J cells. The mRNA and protein expression of each gene were detected by reverse transcription polymerase chain reaction, Western blotting, or enzyme-linked immunosorbent assay. The concentration of intracellular calcium ([Ca]i) was determined by calcium fluorescence mark probe combined with laser scanning confocal microscopy. Compared with the control group, cerulein could upregulate mRNA and protein expression of inflammatory factors, calcium pathway, ghrelin, and [Ca]i. mRNA and protein expression of inflammatory factors increased significantly in cells transfected with ghrelin miRNA compared with the other groups. Intracellular calcium and expression of some calcium pathway proteins decreased significantly in cells transfected with ghrelin miRNA compared with the other groups. Targeted inhibition of ghrelin gene in pancreatic acinar cells of acute pancreatitis can upregulate the expression of the intracellular inflammatory factors and alleviate the intracellular calcium overload.

  19. Anti-ghrelin immunoglobulins modulate ghrelin stability and its orexigenic effect in obese mice and humans

    Science.gov (United States)

    Takagi, Kuniko; Legrand, Romain; Asakawa, Akihiro; Amitani, Haruka; François, Marie; Tennoune, Naouel; Coëffier, Moïse; Claeyssens, Sophie; do Rego, Jean-Claude; Déchelotte, Pierre; Inui, Akio; Fetissov, Sergueï O.

    2013-01-01

    Obese individuals often have increased appetite despite normal plasma levels of the main orexigenic hormone ghrelin. Here we show that ghrelin degradation in the plasma is inhibited by ghrelin-reactive IgG immunoglobulins, which display increased binding affinity to ghrelin in obese patients and mice. Co-administration of ghrelin together with IgG from obese individuals, but not with IgG from anorectic or control patients, increases food intake in rats. Similarly, chronic injections of ghrelin together with IgG from ob/ob mice increase food intake, meal frequency and total lean body mass of mice. These data reveal that in both obese humans and mice, IgG with increased affinity for ghrelin enhances ghrelin’s orexigenic effect, which may contribute to increased appetite and overeating. PMID:24158035

  20. The altered promoter methylation of oxytocin receptor gene in autism.

    Science.gov (United States)

    Elagoz Yuksel, Mine; Yuceturk, Betul; Karatas, Omer Faruk; Ozen, Mustafa; Dogangun, Burak

    Autism spectrum disorder (ASD) is one of the lifelong existing disorders. Abnormal methylation status of gene promoters of oxytonergic system has been implicated as among the etiologic factors of ASDs. We, therefore, investigated the methylation frequency of oxytocin receptor gene (OXTR) promoter from peripheral blood samples of children with autistic features. Our sample includes 66 children in total (22-94 months); 27 children with ASDs according to the DSM-IV-TR and the Childhood Autism Rating Scale (CARS) and 39 children who do not have any autistic like symptoms as the healthy control group. We investigated the DNA methylation status of OXTR promoter by methylation specific enzymatic digestion of genomic DNA and polymerase chain reaction. A significant relationship has been found between ASDs and healthy controls for the reduction of methylation frequency of the regions MT1 and MT3 of OXTR. We could not find any association in the methylation frequency of MT2 and MT4 regions of OXTR. Although our findings indicate high frequency of OXTR promoter hypomethylation in ASDs, there is need for independent replication of the results for a bigger sample set. We expect that future studies with the inclusion of larger, more homogeneous samples will attempt to disentangle the causes of ASDs.

  1. Update of the androgen receptor gene mutations database.

    Science.gov (United States)

    Gottlieb, B; Beitel, L K; Lumbroso, R; Pinsky, L; Trifiro, M

    1999-01-01

    The current version of the androgen receptor (AR) gene mutations database is described. The total number of reported mutations has risen from 309 to 374 during the past year. We have expanded the database by adding information on AR-interacting proteins; and we have improved the database by identifying those mutation entries that have been updated. Mutations of unknown significance have now been reported in both the 5' and 3' untranslated regions of the AR gene, and in individuals who are somatic mosaics constitutionally. In addition, single nucleotide polymorphisms, including silent mutations, have been discovered in normal individuals and in individuals with male infertility. A mutation hotspot associated with prostatic cancer has been identified in exon 5. The database is available on the internet (http://www.mcgill.ca/androgendb/), from EMBL-European Bioinformatics Institute (ftp.ebi.ac.uk/pub/databases/androgen), or as a Macintosh FilemakerPro or Word file (MC33@musica.mcgill.ca). Copyright 1999 Wiley-Liss, Inc.

  2. Expression of androgen receptor target genes in skeletal muscle

    Directory of Open Access Journals (Sweden)

    Kesha Rana

    2014-10-01

    Full Text Available We aimed to determine the mechanisms of the anabolic actions of androgens in skeletal muscle by investigating potential androgen receptor (AR-regulated genes in in vitro and in vivo models. The expression of the myogenic regulatory factor myogenin was significantly decreased in skeletal muscle from testosterone-treated orchidectomized male mice compared to control orchidectomized males, and was increased in muscle from male AR knockout mice that lacked DNA binding activity (ARΔZF2 versus wildtype mice, demonstrating that myogenin is repressed by the androgen/AR pathway. The ubiquitin ligase Fbxo32 was repressed by 12 h dihydrotestosterone treatment in human skeletal muscle cell myoblasts, and c-Myc expression was decreased in testosterone-treated orchidectomized male muscle compared to control orchidectomized male muscle, and increased in AR∆ZF2 muscle. The expression of a group of genes that regulate the transition from myoblast proliferation to differentiation, Tceal7 , p57 Kip2, Igf2 and calcineurin Aa, was increased in AR∆ZF2 muscle, and the expression of all but p57 Kip2 was also decreased in testosterone-treated orchidectomized male muscle compared to control orchidectomized male muscle. We conclude that in males, androgens act via the AR in part to promote peak muscle mass by maintaining myoblasts in the proliferative state and delaying the transition to differentiation during muscle growth and development, and by suppressing ubiquitin ligase-mediated atrophy pathways to preserve muscle mass in adult muscle.

  3. Pharmacogenetics of the β2-Adrenergic Receptor Gene

    Science.gov (United States)

    Ortega, Victor E.; Hawkins, Gregory A.; Peters, Stephen P.; Bleecker, Eugene R.

    2009-01-01

    Asthma is a complex genetic disease with multiple genetic and environmental determinants contributing to the observed variability in response to common anti-asthma therapies. Asthma pharmacogenetic research has focused on multiple candidate genes including the β2-adrenergic receptor gene (ADRβ2) and its effect on individual responses to beta agonist therapy. At present, knowledge about the effects of ADRβ2 variation on therapeutic responses is evolving and should not alter current Asthma Guideline approaches consisting of the use of short acting beta agonists for as-needed symptom based therapy and the use of a regular long-acting beta agonist in combination with inhaled corticosteroid therapy for optimal control of asthma symptoms in those asthmatics who are not controlled on inhaled corticosteroid alone. This approach is based upon studies showing a consistent pharmacogenetic response to regular use of short acting beta agonists (SABA) and less consistent findings in studies evaluating long acting beta agonist (LABA). While emerging pharmacogenetic studies are provocative and should lead to functional approaches, conflicting data with responses to LABA therapy may be caused by factors that include small sample sizes of study populations and differences in experimental design that may limit the conclusions that may be drawn from these clinical trials at the present time. PMID:17996583

  4. Vitamin D Receptor Gene Polymorphisms Associated with Childhood Autism.

    Science.gov (United States)

    Cieślińska, Anna; Kostyra, Elżbieta; Chwała, Barbara; Moszyńska-Dumara, Małgorzata; Fiedorowicz, Ewa; Teodorowicz, Małgorzata; Savelkoul, Huub F J

    2017-09-09

    Autism spectrum disorder (ASD) is a group of heterogeneous, behaviorally defined disorders whereby currently no biological markers are common to all affected individuals. A deregulated immune response may be contributing to the etiology of ASD. The active metabolite of vitamin D₃ has an immunoregulatory role mediated by binding to the vitamin D receptor (VDR) in monocyte, macrophages, and lymphocytes. The effects of vitamin D and interaction with the VDR may be influenced by polymorphism in the VDR gene. Genetic association of four different VDR polymorphisms (Apa-I, Bsm-I, Taq-I, Fok-I) associated with susceptibility to the development of autism in children was investigated. We uniquely found an association between the presence of the T allele at position Taq-I and presence of the a allele at position Apa-I of the VDR gene with decreased ASD incidence. There was also an association between female gender and the presence of the T allele. We found no statistical significant correlation between VDR single nucleotide polymorphisms (SNPs) and vitamin D₃ concentration in serum of ASD children. Genetic polymorphism in two SNP in VDR may be correlated with development of ASD symptoms by influencing functionality of vitamin D₃ metabolism, while vitamin D₃ levels were not significantly different between ASD and non-ASD children.

  5. Ghrelin is involved in the paracrine communication between neurons and glial cells.

    Science.gov (United States)

    Avau, B; De Smet, B; Thijs, T; Geuzens, A; Tack, J; Vanden Berghe, P; Depoortere, I

    2013-09-01

    Ghrelin is the only known peripherally active orexigenic hormone produced by the stomach that activates vagal afferents to stimulate food intake and to accelerate gastric emptying. Vagal sensory neurons within the nodose ganglia are surrounded by glial cells, which are able to receive and transmit chemical signals. We aimed to investigate whether ghrelin activates or influences the interaction between both types of cells. The effect of ghrelin was compared with that of leptin and cholecystokinin (CCK). Cultures of rat nodose ganglia were characterized by immunohistochemistry and the functional effects of peptides, neurotransmitters, and pharmacological blockers were measured by Ca(2+) imaging using Fluo-4-AM as an indicator. Neurons responded to KCl and were immunoreactive for PGP-9.5 whereas glial cells responded to lysophosphatidic acid and had the typical SOX-10-positive nuclear staining. Neurons were only responsive to CCK (31 ± 5%) whereas glial cells responded equally to the applied stimuli: ghrelin (27 ± 2%), leptin (21 ± 2%), and CCK (30 ± 2%). In contrast, neurons stained more intensively for the ghrelin receptor than glial cells. ATP induced [Ca(2+) ]i rises in 90% of the neurons whereas ACh and the NO donor, SIN-1, mainly induced [Ca(2+) ]i changes in glial cells (41 and 51%, respectively). The percentage of ghrelin-responsive glial cells was not affected by pretreatment with suramin, atropine, hexamethonium or 1400 W, but was reduced by l-NAME and by tetrodotoxin. Neurons were shown to be immunoreactive for neuronal NO-synthase (nNOS). Our data show that ghrelin induces Ca(2+) signaling in glial cells of the nodose ganglion via the release of NO originating from the neurons. © 2013 John Wiley & Sons Ltd.

  6. Effects of ghrelin on the apoptosis of human neutrophils in vitro

    Science.gov (United States)

    Li, Bin; Zeng, Mian; Zheng, Haichong; Huang, Chunrong; He, Wanmei; Lu, Guifang; Li, Xia; Chen, Yanzhu; Xie, Ruijie

    2016-01-01

    Acute respiratory distress syndrome (ARDS) is characterized by lung inflammation and the diffuse infiltration of neutrophils into the alveolar space. Neutrophils are abundant, short-lived leukocytes that play a key role in immune defense against microbial infections. These cells die via apoptosis following the activation and uptake of microbes, and will also enter apoptosis spontaneously at the end of their lifespan if they do not encounter pathogens. Apoptosis is essential for the removal of neutrophils from inflamed tissues and for the timely resolution of neutrophilic inflammation. Ghrelin is an endogenous ligand for the growth hormone (GH) secretagogue receptor, produced and secreted mainly from the stomach. Previous studies have reported that ghrelin exerts anti-inflammatory effects in lung injury through the regulation of the apoptosis of different cell types; however, the ability of ghrelin to regulate alveolar neutrophil apoptosis remains largely undefined. We hypothesized that ghrelin may have the ability to modulate neutrophil apoptosis. In this study, to examine this hypothesis, we investigated the effects of ghrelin on freshly isolated neutrophils in vitro. Our findings demonstrated a decrease in the apoptotic ratio (as shown by flow cytometry), as well as in the percentage of cells with decreased mitochondrial membrane potential (ΔΨm) and in the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick-end labeling-positive rate, accompanied by an increased B-cell lymphoma 2/Bax ratio and the downregulation of cleaved caspase-3 in neutrophils following exposure to lipopolysaccharide (100 ng/ml). However, pre-treatment with ghrelin at a physiological level (100 nM) did not have a notable influence on the neutrophils in all the aforementioned tests. Our findings suggest that ghrelin may not possess the ability to modulate the neutrophil lifespan in vitro. PMID:27431014

  7. [Obesity studies in candidate genes].

    Science.gov (United States)

    Ochoa, María del Carmen; Martí, Amelia; Martínez, J Alfredo

    2004-04-17

    There are more than 430 chromosomic regions with gene variants involved in body weight regulation and obesity development. Polymorphisms in genes related to energy expenditure--uncoupling proteins (UCPs), related to adipogenesis and insulin resistance--hormone-sensitive lipase (HLS), peroxisome proliferator-activated receptor gamma (PPAR gamma), beta adrenergic receptors (ADRB2,3), and alfa tumor necrosis factor (TNF-alpha), and related to food intake--ghrelin (GHRL)--appear to be associated with obesity phenotypes. Obesity risk depends on two factors: a) genetic variants in candidate genes, and b) biographical exposure to environmental risk factors. It is necessary to perform new studies, with appropriate control groups and designs, in order to reach relevant conclusions with regard to gene/environmental (diet, lifestyle) interactions.

  8. Ghrelin increases intracellular Ca²⁺ concentration in the various hormone-producing cell types of the rat pituitary gland.

    Science.gov (United States)

    Yamazaki, Mami; Aizawa, Sayaka; Tanaka, Toru; Sakai, Takafumi; Sakata, Ichiro

    2012-09-20

    Ghrelin, isolated from the stomach as an endogenous ligand for the growth hormone secretagogue receptor (GHS-R), has potent growth hormone release ability in vivo and in vitro. Although GHS-R is abundantly expressed in the pituitary gland, there is no direct evidence of a relationship between hormone-producing cells and functional GHS-R in the pituitary gland. The aim of this study was to determine which anterior pituitary cells respond to ghrelin stimulation in male rats. We performed Fura-2 Ca(2+) imaging analysis using isolated pituitary cells, and performed immunocytochemistry to identify the type of pituitary hormone-producing cells. In Fura-2 Ca(2+) imaging analysis, ghrelin administration increased the intracellular Ca(2+) concentration in approximately 50% of total isolated anterior pituitary cells, and 20% of these cells strongly responded to ghrelin. Immunocytochemical analysis revealed that 82.9 ± 1.3% of cells that responded to ghrelin stimulation were GH-immunopositive. On the other hand, PRL-, LH-, and ACTH-immunopositive cells constituted 2.0 ± 0.3%, 12.6 ± 0.3%, and 2.5 ± 0.8% of ghrelin-responding pituitary cells, respectively. TSH-immunopositive cells did not respond to ghrelin treatment. These results suggest that ghrelin directly acts not only on somatotrophs, but also on mammotrophs, gonadotrophs, and corticotrophs in the rat pituitary gland. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  9. Polymorphisms of genes coding for ghrelin and its receptor in relation to colorectal cancer risk: a two-step gene-wide case-control study

    Czech Academy of Sciences Publication Activity Database

    Campa, D.; Pardini, Barbara; Naccarati, Alessio; Vodičková, Ludmila; Novotný, J.; Steinke, V.; Rahner, N.; Holinski-Feder, E.; Morak, M.; Schackert, H. K.; Görgens, H.; Kötting, J.; Betz, B.; Kloor, M.; Engel, C.; Büttner, R.; Propping, P.; Försti, A.; Hemminki, K.; Barale, R.; Vodička, Pavel; Canzian, F.

    2010-01-01

    Roč. 10, - (2010), s. 112-117 ISSN 1471-230X R&D Projects: GA ČR GA310/05/2626 Institutional research plan: CEZ:AV0Z50390512 Keywords : colorectal cancer * insulin * GHSR Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.468, year: 2010

  10. Developing a System for Directed Gene Introduction into Mammary Gland Via Targeted Infection of Retrovirus Receptor Transgenics

    National Research Council Canada - National Science Library

    Bates, Paul

    1998-01-01

    ... (the Rous sarcoma virus receptor). Directed infection, and thus directed gene expression of cells expressing the viral receptor should provide a rapid and efficient method to test the mammary tumorigenic potential of genes in an animal model...

  11. Modulation of neuronal network activity with ghrelin

    NARCIS (Netherlands)

    Stoyanova, Irina; Rutten, Wim; le Feber, Jakob

    2012-01-01

    Ghrelin is a neuropeptide regulating multiple physiological processes, including high brain functions such as learning and memory formation. However, the effect of ghrelin on network activity patterns and developments has not been studied yet. Therefore, we used dissociated cortical neurons plated

  12. Ghrelin signalling on food reward: a salient link between the gut and the mesolimbic system.

    Science.gov (United States)

    Perello, M; Dickson, S L

    2015-06-01

    'Hunger is the best spice' is an old and wise saying that acknowledges the fact that almost any food tastes better when we are hungry. The neurobiological underpinnings of this lore include activation of the brain's reward system and the stimulation of this system by the hunger-promoting hormone ghrelin. Ghrelin is produced largely from the stomach and levels are higher preprandially. The ghrelin receptor is expressed in many brain areas important for feeding control, including not only the hypothalamic nuclei involved in energy balance regulation, but also reward-linked areas such as the ventral tegmental area. By targeting the mesoaccumbal dopamine neurones of the ventral tegmental area, ghrelin recruits pathways important for food reward-related behaviours that show overlap with but are also distinct from those important for food intake. We review a variety of studies that support the notion that ghrelin signalling at the level of the mesolimbic system is one of the key molecular substrates that provides a physiological signal connecting gut and reward pathways. © 2014 The Authors. Journal of Neuroendocrinology published by John Wiley & Sons Ltd on behalf of British Society for Neuroendocrinology.

  13. Systematic study of association of four GABAergic genes: glutamic acid decarboxylase 1 gene, glutamic acid decarboxylase 2 gene, GABA(B) receptor 1 gene and GABA(A) receptor subunit beta2 gene, with schizophrenia using a universal DNA microarray.

    Science.gov (United States)

    Zhao, Xu; Qin, Shengying; Shi, Yongyong; Zhang, Aiping; Zhang, Jing; Bian, Li; Wan, Chunling; Feng, Guoyin; Gu, Niufan; Zhang, Guangqi; He, Guang; He, Lin

    2007-07-01

    Several studies have suggested the dysfunction of the GABAergic system as a risk factor in the pathogenesis of schizophrenia. In the present study, case-control association analysis was conducted in four GABAergic genes: two glutamic acid decarboxylase genes (GAD1 and GAD2), a GABA(A) receptor subunit beta2 gene (GABRB2) and a GABA(B) receptor 1 gene (GABBR1). Using a universal DNA microarray procedure we genotyped a total of 20 SNPs on the above four genes in a study involving 292 patients and 286 controls of Chinese descent. Statistically significant differences were observed in the allelic frequencies of the rs187269C/T polymorphism in the GABRB2 gene (P=0.0450, chi(2)=12.40, OR=1.65) and the -292A/C polymorphism in the GAD1 gene (P=0.0450, chi(2)=14.64 OR=1.77). In addition, using an electrophoretic mobility shift assay (EMSA), we discovered differences in the U251 nuclear protein binding to oligonucleotides representing the -292 SNP on the GAD1 gene, which suggests that the -292C allele has reduced transcription factor binding efficiency compared with the 292A allele. Using the multifactor-dimensionality reduction method (MDR), we found that the interactions among the rs187269C/T polymorphism in the GABRB2 gene, the -243A/G polymorphism in the GAD2 gene and the 27379C/T and 661C/T polymorphisms in the GAD1 gene revealed a significant association with schizophrenia (Pschizophrenia in the Chinese population.

  14. Expression of glucocorticoid and progesterone nuclear receptor genes in archival breast cancer tissue

    International Nuclear Information System (INIS)

    Smith, Robert A; Lea, Rod A; Curran, Joanne E; Weinstein, Stephen R; Griffiths, Lyn R

    2003-01-01

    Previous studies in our laboratory have shown associations of specific nuclear receptor gene variants with sporadic breast cancer. In order to investigate these findings further, we conducted the present study to determine whether expression levels of the progesterone and glucocorticoid nuclear receptor genes vary in different breast cancer grades. RNA was extracted from paraffin-embedded archival breast tumour tissue and converted into cDNA. Sample cDNA underwent PCR using labelled primers to enable quantitation of mRNA expression. Expression data were normalized against the 18S ribosomal gene multiplex and analyzed using analysis of variance. Analysis of variance indicated a variable level of expression of both genes with regard to breast cancer grade (P = 0.00033 for glucocorticoid receptor and P = 0.023 for progesterone receptor). Statistical analysis indicated that expression of the progesterone nuclear receptor is elevated in late grade breast cancer tissue

  15. Takotsubo syndrome and estrogen receptor genes: partners in crime?

    Science.gov (United States)

    Pizzino, Gabriele; Bitto, Alessandra; Crea, Pasquale; Khandheria, Bijoy; Vriz, Olga; Carerj, Scipione; Squadrito, Francesco; Minisini, Rosalba; Citro, Rodolfo; Cusmà-Piccione, Maurizio; Madaffari, Antonio; Andò, Giuseppe; Altavilla, Domenica; Zito, Concetta

    2017-04-01

    We aimed to analyze genetic polymorphism of estrogen receptor (ESR) 1 and ESR2 in a series of postmenopausal women with Takotsubo syndrome (TS). In total, 81 consecutive white women were prospectively enrolled: 22 with TS (TS group; mean age 71.2 ± 9.8 years), 22 with acute myocardial infarction (MI group; mean age 73.2 ± 8 years), and 37 asymptomatic healthy controls (CTRL group; mean age 69 ± 4.2 years). Genotyping of ESR1 -397C>T (rs2234693) and -351A>G (rs9340799) and ESR2 -1839G>T (rs 1271572) and 1082G>A (rs1256049) genetic variants was performed. We estimated the odds ratio (OR) between the genotype of each examined locus with the occurrence of TS or MI. The risk of experiencing TS was higher for those study participants carrying the T allele at the rs2234693 locus of the ESR1 gene [OR: 2.0, 95% confidence interval (CI): 0.973-4.11, P = 0.04, TS vs. MI + CTRL; OR: 2.79, 95% CI: 1.17-6.64, P = 0.016, TS vs. MI alone]. Women carrying a T allele at the rs1271572 locus of the ESR2 gene demonstrated an even higher risk (OR: 3.23, 95% CI: 1.55-6.73, P = 0.0019, TS vs. MI + CTRL; OR: 9.13, 95% CI: 2.78-29.9, P = 0.0001, TS vs. MI alone). The study reports preliminary findings suggesting a possible link between ESR polymorphisms and the occurrence of TS. Larger studies are needed to confirm our results.

  16. The effect of intravenous injection of Ghrelin on the mean plasma concentrations of insulin in immature camels fed different levels of their energy requirements

    Directory of Open Access Journals (Sweden)

    2009-11-01

    Ghrelin is a peptide hormone secreted into the circulation from the stomach, but this peptide is also synthetized in a number of different body tissues including the brain and pancreas, suggesting both endocrine and paracrine effects. These include: stimulation of GH and ACTH secretion, an increase in appetite and diabetogenic effect on carbohydrate metabolism. Furthermore, ghrelin is the natural ligand of the growth hormone secretagogue receptor (GHS-R. Ghrelin and its mRNAas well as GH secretagogue receptor mRNAs are expressed in the pancreas and islet cells and regulates insulin release and glucose metabolism, but because the effect of ghrelin on insulin secretion before puberty in semiruminant animals has never been examined,   therefore the purpose of the present research was to determine the effect of ghrelin on insulin secretion before puberty in camels. In this investigation 12 camels were randomly divided into two groups. Animals in each group were fed either 50% and 100% energy content in diet for 2 weeks. After 2 weeks camels received 8 μg ghrelin/kg body weight via their jugular vein for 4 days. Blood samples were collected from the jugular vein of all animals before, during (30 minutes after injection of ghrelin and after the intervention for 4 continuous days and plasma insulin concentrations determined by RIA. Data obtained were analyzed by repeated measures –ANOVA and paired t-Test. p

  17. The ghrelin signalling system is involved in the consumption of sweets.

    Directory of Open Access Journals (Sweden)

    Sara Landgren

    Full Text Available The gastric-derived orexigenic peptide ghrelin affects brain circuits involved in energy balance as well as in reward. Indeed, ghrelin activates an important reward circuit involved in natural- as well as drug-induced reward, the cholinergic-dopaminergic reward link. It has been hypothesized that there is a common reward mechanism for alcohol and sweet substances in both animals and humans. Alcohol dependent individuals have higher craving for sweets than do healthy controls and the hedonic response to sweet taste may, at least in part, depend on genetic factors. Rat selectively bred for high sucrose intake have higher alcohol consumption than non-sucrose preferring rats and vice versa. In the present study a group of alcohol-consuming individuals selected from a population cohort was investigated for genetic variants of the ghrelin signalling system in relation to both their alcohol and sucrose consumption. Moreover, the effects of GHS-R1A antagonism on voluntary sucrose-intake and operant self-administration, as well as saccharin intake were investigated in preclinical studies using rodents. The effects of peripheral grelin administration on sucrose intake were also examined. Here we found associations with the ghrelin gene haplotypes and increased sucrose consumption, and a trend for the same association was seen in the high alcohol consumers. The preclinical data show that a GHS-R1A antagonist reduces the intake and self-administration of sucrose in rats as well as saccharin intake in mice. Further, ghrelin increases the intake of sucrose in rats. Collectively, our data provide a clear indication that the GHS-R1A antagonists reduces and ghrelin increases the intake of rewarding substances and hence, the central ghrelin signalling system provides a novel target for the development of drug strategies to treat addictive behaviours.

  18. The Oxytocin Receptor Gene ( OXTR) and Face Recognition.

    Science.gov (United States)

    Verhallen, Roeland J; Bosten, Jenny M; Goodbourn, Patrick T; Lawrance-Owen, Adam J; Bargary, Gary; Mollon, J D

    2017-01-01

    A recent study has linked individual differences in face recognition to rs237887, a single-nucleotide polymorphism (SNP) of the oxytocin receptor gene ( OXTR; Skuse et al., 2014). In that study, participants were assessed using the Warrington Recognition Memory Test for Faces, but performance on Warrington's test has been shown not to rely purely on face recognition processes. We administered the widely used Cambridge Face Memory Test-a purer test of face recognition-to 370 participants. Performance was not significantly associated with rs237887, with 16 other SNPs of OXTR that we genotyped, or with a further 75 imputed SNPs. We also administered three other tests of face processing (the Mooney Face Test, the Glasgow Face Matching Test, and the Composite Face Test), but performance was never significantly associated with rs237887 or with any of the other genotyped or imputed SNPs, after corrections for multiple testing. In addition, we found no associations between OXTR and Autism-Spectrum Quotient scores.

  19. Glucocorticoid Receptor Related Genes: Genotype And Brain Gene Expression Relationships To Suicide And Major Depressive Disorder

    Science.gov (United States)

    Pantazatos, Spiro P.; Huang, Yung-yu; Rosoklija, Gorazd B.; Dwork, Andrew J.; Burke, Ainsley; Arango, Victoria; Oquendo, Maria A.; Mann, J. John

    2016-01-01

    Introduction We tested the relationship between genotype, gene expression and suicidal behavior and MDD in live subjects and postmortem samples for three genes, associated with the hypothalamic-pituitary-adrenal axis, suicidal behavior and major depressive disorder (MDD); FK506 binding protein 5 (FKBP5), Spindle and kinetochore-associated protein 2 (SKA2) and Glucocorticoid Receptor (NR3C1). Materials and Methods Single-nucleotide polymorphisms (SNPs) and haplotypes were tested for association with suicidal behavior and MDD in a live (N=277) and a postmortem sample (N=209). RNA-seq was used to examine gene and isoform-level brain expression postmortem (Brodmann Area 9) (N=59). Expression quantitative trait loci (eQTL) relationships were examined using a public database (UK Brain Expression Consortium). Results We identified a haplotype within the FKBP5 gene, present in 47% of the live subjects, that was associated with increased risk of suicide attempt (OR=1.58, t=6.03, p=0.014). Six SNPs on this gene, three SNPs on SKA2 and one near NR3C1 showed before-adjustment association with attempted suicide, and two SNPs of SKA2 with suicide death, but none stayed significant after adjustment for multiple testing. Only the SKA2 SNPs were related to expression in the prefrontal cortex. One NR3C1 transcript had lower expression in suicide relative to non-suicide sudden death cases (b=-0.48, SE=0.12, t=-4.02, adjusted p=0.004). Conclusion We have identified an association of FKBP5 haplotype with risk of suicide attempt and found an association between suicide and altered NR3C1 gene expression in the prefrontal cortex. Our findings further implicate hypothalamic pituitary axis dysfunction in suicidal behavior. PMID:27030168

  20. Functional characterization of bursicon receptor and genome-wide analysis for identification of genes affected by bursicon receptor RNAi

    Science.gov (United States)

    Bai, Hua; Palli, Subba R.

    2010-01-01

    Bursicon is an insect neuropeptide hormone that is secreted from the central nervous system into the hemolymph and initiates cuticle tanning. The receptor for bursicon is encoded by the rickets (rk) gene and belongs to the G protein-coupled receptor (GPCR) superfamily. The bursicon and its receptor regulate cuticle tanning as well as wing expansion after adult eclosion. However, the molecular action of bursicon signaling remains unclear. We utilized RNA interference (RNAi) and microarray to study the function of the bursicon receptor (Tcrk) in the model insect, Tribolium castaneum. The data included here showed that in addition to cuticle tanning and wing expansion reported previously, Tcrk is also required for development and expansion of integumentary structures and adult eclosion. Using custom microarrays, we identified 24 genes that are differentially expressed between Tcrk RNAi and control insects. Knockdown in the expression of one of these genes, TC004091, resulted in the arrest of adult eclosion. Identification of genes that are involved in bursicon receptor mediated biological processes will provide tools for future studies on mechanisms of bursicon action. PMID:20457145

  1. The Medicago truncatula lysine motif-receptor-like kinase gene family includes NFP and new nodule-expressed genes

    NARCIS (Netherlands)

    Arrighi, J.F.; Barre, A.; Amor, Ben B.; Bersoult, A.; Campos Soriano, L.; Mirabella, R.; Carvalho-Niebel, de F.; Journet, E.P.; Ghérardi, M.; Huguet, T.; Geurts, R.; Dénarié, J.; Rougé, P.; Gough, C.

    2006-01-01

    Rhizobial Nod factors are key symbiotic signals responsible for starting the nodulation process in host legume plants. Of the six Medicago truncatula genes controlling a Nod factor signaling pathway, Nod Factor Perception (NFP) was reported as a candidate Nod factor receptor gene. Here, we provide

  2. Nutritional State-Dependent Ghrelin Activation of Vasopressin Neurons via Retrograde Trans-Neuronal–Glial Stimulation of Excitatory GABA Circuits

    Science.gov (United States)

    Haam, Juhee; Halmos, Katalin C.; Di, Shi

    2014-01-01

    Behavioral and physiological coupling between energy balance and fluid homeostasis is critical for survival. The orexigenic hormone ghrelin has been shown to stimulate the secretion of the osmoregulatory hormone vasopressin (VP), linking nutritional status to the control of blood osmolality, although the mechanism of this systemic crosstalk is unknown. Here, we show using electrophysiological recordings and calcium imaging in rat brain slices that ghrelin stimulates VP neurons in the hypothalamic paraventricular nucleus (PVN) in a nutritional state-dependent manner by activating an excitatory GABAergic synaptic input via a retrograde neuronal–glial circuit. In slices from fasted rats, ghrelin activation of a postsynaptic ghrelin receptor, the growth hormone secretagogue receptor type 1a (GHS-R1a), in VP neurons caused the dendritic release of VP, which stimulated astrocytes to release the gliotransmitter adenosine triphosphate (ATP). ATP activation of P2X receptors excited presynaptic GABA neurons to increase GABA release, which was excitatory to the VP neurons. This trans-neuronal–glial retrograde circuit activated by ghrelin provides an alternative means of stimulation of VP release and represents a novel mechanism of neuronal control by local neuronal–glial circuits. It also provides a potential cellular mechanism for the physiological integration of energy and fluid homeostasis. PMID:24790191

  3. Oleocanthal Modulates Estradiol-Induced Gene Expression Involving Estrogen Receptor α.

    Science.gov (United States)

    Keiler, Annekathrin Martina; Djiogue, Sefirin; Ehrhardt, Tino; Zierau, Oliver; Skaltsounis, Leandros; Halabalaki, Maria; Vollmer, Günter

    2015-09-01

    Oleocanthal is a bioactive compound from olive oil. It has attracted considerable attention as it is anti-inflammatory, antiproliferative, and has been shown to possess neuroprotective properties in vitro and in vivo. Delineated from its polyphenolic structure, the aim of this study was to characterize oleocanthal towards estrogenic properties. This might contribute to partly explain the beneficial effects described for the Mediterranean diet. Estrogenic properties of oleocanthal were assessed by different methods: a) stimulation of reporter gene activity in MVLN or RNDA cells either expressing estrogen receptor α or β, b) stimulation of luciferase reporter gene activity in U2OS osteosarcoma cells expressing estrogen receptor α or β, and c) elucidation of the impact on estradiol-induced gene expression in U2OS cells transduced with both estrogen receptors. Depending on the cell line origin, oleocanthal inhibited luciferase activity (MVLN, U2OS-estrogen receptor β) or weakly induced reporter gene activity at 10 µM in U2OS-estrogen receptor α cells. However, oleocanthal inhibited stimulation of luciferase activity by estradiol from both estrogen receptors. Oleocanthal, if given alone, did not stimulate gene expression in U2OS cells, but it significantly modulated the response of estradiol. Oleocanthal enhanced the effect of estradiol on the regulation of those genes, which are believed to be regulated through heterodimeric estrogen receptors. As the estrogenic response pattern of oleocanthal is rather unique, we compared the results obtained with oleacein. Oleocanthal binds to both estrogen receptors inducing estradiol-agonistic or antiagonistic effects depending on the cell line. Regarding regulation of gene expression in U2OS-estrogen receptor α/β cells, oleocanthal and oleacein enhanced estradiol-mediated regulation of heterodimer-regulated genes. Georg Thieme Verlag KG Stuttgart · New York.

  4. Ghrelin and GHS-R1A signaling within the ventral and laterodorsal tegmental area regulate sexual behavior in sexually naïve male mice.

    Science.gov (United States)

    Prieto-Garcia, Luna; Egecioglu, Emil; Studer, Erik; Westberg, Lars; Jerlhag, Elisabet

    2015-12-01

    In addition to food intake and energy balance regulation, ghrelin mediate the rewarding and motivational properties of palatable food as well as addictive drugs. The ability of ghrelin to regulate reinforcement involves the cholinergic-dopaminergic reward link, which encompasses a cholinergic projection from the laterodorsal tegmental area (LDTg) to the ventral tegmental area (VTA) together with mesolimbic dopaminergic projections from the VTA to the nucleus accumbens (NAc). Recently, systemic ghrelin was shown to regulate sexual behavior and motivation in male mice via dopamine neurotransmission. The present study therefore elucidates the role of ghrelin and ghrelin receptor (GHS-R1A) antagonist treatment within NAc, VTA or LDTg for sexual behavior in sexually naïve male mice. Local administration of the GHSR-1A antagonist, JMV2959, into the VTA or LDTg was found to reduce the preference for female mice, the number of mounts and the duration of mounting as well as to prolong the latency to mount. This was further substantiated by the findings that ghrelin administration into the VTA or LDTg increased the number of mounts and the duration of mounting and decreased the latency to mount. Moreover, ghrelin administered into the LDTg increased the preference for female mice. Accumbal administration of ghrelin increased whereas GHS-R1A antagonist decreased the intake of palatable food, but did not alter sexual behavior. In males exposed to sexual interaction, systemic administration of ghrelin increases whereas JMV2959 decreases the turnover of dopamine in the VTA. These data suggest that ghrelin signaling within the tegmental areas is required for sexual behavior in sexually naïve male mice. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  5. Effects of peripherally and centrally applied ghrelin on the oxidative stress induced by renin angiotensin system in a rat model of renovascular hypertension.

    Science.gov (United States)

    Boshra, Vivian; Abbas, Amr M

    2017-07-26

    Renovascular hypertension (RVH) is a result of renal artery stenosis, which is commonly due to astherosclerosis. In this study, we aimed to clarify the central and peripheral effects of ghrelin on the renin-angiotensin system (RAS) in a rat model of RVH. RVH was induced in rats by partial subdiaphragmatic aortic constriction. Experiment A was designed to assess the central effect of ghrelin via the intracerebroventricular (ICV) injection of ghrelin (5 μg/kg) or losartan (0.01 mg/kg) in RVH rats. Experiment B was designed to assess the peripheral effect of ghrelin via the subcutaneous (SC) injection of ghrelin (150 μg/kg) or losartan (10 mg/kg) for 7 consecutive days. Mean arterial blood pressure (MAP), heart rate, plasma renin activity (PRA), and oxidative stress markers were measured in all rats. In addition, angiotensin II receptor type 1 (AT1R) concentration was measured in the hypothalamus of rats in Experiment B. RVH significantly increased brain AT1R, PRA, as well as the brain and plasma oxidative stress. Either SC or ICV ghrelin or losartan caused a significant decrease in MAP with no change in the heart rate. Central ghrelin or losartan caused a significant decrease in brain AT1R with significant alleviation of the brain oxidative stress. Central ghrelin caused a significant decrease in PRA, whereas central losartan caused a significant increase in PRA. SC ghrelin significantly decreased PRA and plasma oxidative stress, whereas SC losartan significantly increased PRA and decreased plasma oxidative stress. The hypotensive effect of ghrelin is mediated through the amelioration of oxidative stress, which is induced by RAS centrally and peripherally.

  6. Long-acting octreotide treatment causes a sustained decrease in ghrelin concentrations but does not affect weight, behaviour and appetite in subjects with Prader-Willi syndrome.

    Science.gov (United States)

    De Waele, Kathleen; Ishkanian, Stacey L; Bogarin, Roberto; Miranda, Charmaine A; Ghatei, Mohammad A; Bloom, Stephen R; Pacaud, Danièle; Chanoine, Jean-Pierre

    2008-10-01

    Ghrelin is secreted primarily by the stomach and circulates as both acylated and desacyl ghrelin. Acylated (but not desacyl) ghrelin stimulates appetite. Both concentrations are elevated in Prader-Willi syndrome (PWS), suggesting that ghrelin may contribute to hyperphagia and overweight in these subjects. We evaluated whether long-acting octreotide (Oct) decreases acylated and desacyl ghrelin concentrations, body mass, appetite and compulsive behaviour towards food in adolescents with PWS. A 56-week prospective, randomized, cross-over trial. Nine subjects with PWS (age 14.6 (10.8-18.9) years, body mass index (BMI) Z-score +1.9 (0.6-3.0)) received either Oct (30 mg) or saline i.m. every 4 weeks for 16 weeks and were switched over to the other treatment after a 24-week washout period. Eight subjects completed the study. Oct caused a decrease in both acylated (-53%) and desacyl (-54%) fasting ghrelin concentrations (P<0.05) but did not significantly affect BMI. Oct had no significant effect on peptide YY concentrations, appetite or compulsive behaviour towards food. Oct caused a decrease in insulin-like growth factor-I concentrations, an increase in HbA1c and transient elevation of blood glucose in two subjects. Three subjects developed gallstones. Oct treatment caused a prolonged decrease in ghrelin concentrations in adolescents with PWS but did not improve body mass or appetite. Future intervention studies aiming at clarifying the role of ghrelin in PWS should focus on the administration of specific inhibitors of ghrelin secretion or ghrelin receptor activity that do not interfere with other appetite-regulating peptides.

  7. A novel human gene encoding a G-protein-coupled receptor (GPR15) is located on chromosome 3

    Energy Technology Data Exchange (ETDEWEB)

    Heiber, M.; Marchese, A.; O`Dowd, B.F. [Univ. of Toronto, Ontario (Canada)] [and others

    1996-03-05

    We used sequence similarities among G-protein-coupled receptor genes to discover a novel receptor gene. Using primers based on conserved regions of the opioid-related receptors, we isolated a PCR product that was used to locate the full-length coding region of a novel human receptor gene, which we have named GPR15. A comparison of the amino acid sequence of the receptor gene, which we have named GPR15. A comparison of the amino acid sequence of the receptor encoded by GPR15 with other receptors revealed that it shared sequence identity with the angiotensin II AT1 and AT2 receptors, the interleukin 8b receptor, and the orphan receptors GPR1 and AGTL1. GPR15 was mapped to human chromosome 3q11.2-q13.1. 12 refs., 2 figs.

  8. Functional polymorphisms in the P2X7 receptor gene are associated with osteoporosis

    DEFF Research Database (Denmark)

    Husted, L B; Harsløf, T; Stenkjær, L

    2013-01-01

    variant allele, which has been associated with increased receptor function in monocytes, was associated with increased total hip BMD in women. With the exception of His155Tyr for which we found conflicting results in men and women, our results are consistent with the phenotype of the knockout mouse......UNLABELLED: The P2X(7) receptor is an ATP-gated cation channel. We investigated the effect of both loss-of-function and gain-of-function polymorphisms in the P2X(7) receptor gene on BMD and risk of vertebral fractures and found that five polymorphisms and haplotypes containing three...... of these polymorphisms were associated with BMD and fracture risk. INTRODUCTION: The P2X(7) receptor is an ATP-gated cation channel. P2X(7) receptor knockout mice have reduced total bone mineral content, and because several functional polymorphisms have been identified in the human P2X(7) receptor gene, we wanted...

  9. Ghrelin in the pilosebaceous unit: alteration of ghrelin in patients with acne vulgaris.

    Science.gov (United States)

    Cicek, Demet; Demir, Betul; Erder, Ilker; Kuloglu, Tuncay; Ucer, Ozlem; Aydin, Suleyman; Ucak, Haydar; Dertlioglu, Selma; Kalayci, Mehmet

    2015-01-01

    Ghrelin in the pilosebaceous tissues of human skin and ghrelin levels in patients with acne vulgaris have not yet been investigated. The purpose of this study was to screen ghrelin immunoreactivity by immunohistochemistry in human pilosebaceous tissues of human skin and also to determine the quantities of ghrelin in the serum of the patients with acne vulgaris. 30 patients presenting with acne vulgaris and 30 control subjects participated in this study. Ghrelin levels were determined by enzyme linked immunosorbent assay (ELISA). Human hair follicles and sebaceous glands were immunohistochemically examined. Immunohistochemistry results showed that there is a strong ghrelin immunoreactivity in the hair follicles and sebaceous glands in sections of human skin. The mean serum ghrelin levels (27.58 ・} 15.44 pg/mL) in patients with acne vulgaris was significantly lower than those of controls (35.62・}20.46 pg/mL). Ghrelin produced in hair follicles and sebaceous glands of the skin might participate in the pathogenesis of acne vulgaris and also acne vulgaris in humans might be associated with decreased serum ghrelin.

  10. Ghrelin plasma levels, gastric ghrelin cell density and bone mineral density in women with rheumatoid arthritis.

    Science.gov (United States)

    Maksud, F A N; Kakehasi, A M; Guimarães, M F B R; Machado, C J; Barbosa, A J A

    2017-05-18

    Generalized bone loss can be considered an extra-articular manifestation of rheumatoid arthritis (RA) that may lead to the occurrence of fractures, resulting in decreased quality of life and increased healthcare costs. The peptide ghrelin has demonstrated to positively affect osteoblasts in vitro and has anti-inflammatory actions, but the studies that correlate ghrelin plasma levels and RA have contradictory results. We aimed to evaluate the correlation between total ghrelin plasma levels, density of ghrelin-immunoreactive cells in the gastric mucosa, and bone mineral density (BMD) in twenty adult women with established RA with 6 months or more of symptoms (mean age of 52.70±11.40 years). Patients with RA presented higher ghrelin-immunoreactive cells density in gastric mucosa (P=0.008) compared with healthy females. There was a positive relationship between femoral neck BMD and gastric ghrelin cell density (P=0.007). However, these same patients presented a negative correlation between plasma ghrelin levels and total femoral BMD (P=0.03). The present results indicate that ghrelin may be involved in bone metabolism of patients with RA. However, the higher density of ghrelin-producing cells in the gastric mucosa of these patients does not seem to induce a corresponding elevation in the plasma levels of this peptide.

  11. Ghrelin plasma levels, gastric ghrelin cell density and bone mineral density in women with rheumatoid arthritis

    Directory of Open Access Journals (Sweden)

    F.A.N. Maksud

    Full Text Available Generalized bone loss can be considered an extra-articular manifestation of rheumatoid arthritis (RA that may lead to the occurrence of fractures, resulting in decreased quality of life and increased healthcare costs. The peptide ghrelin has demonstrated to positively affect osteoblasts in vitro and has anti-inflammatory actions, but the studies that correlate ghrelin plasma levels and RA have contradictory results. We aimed to evaluate the correlation between total ghrelin plasma levels, density of ghrelin-immunoreactive cells in the gastric mucosa, and bone mineral density (BMD in twenty adult women with established RA with 6 months or more of symptoms (mean age of 52.70±11.40 years. Patients with RA presented higher ghrelin-immunoreactive cells density in gastric mucosa (P=0.008 compared with healthy females. There was a positive relationship between femoral neck BMD and gastric ghrelin cell density (P=0.007. However, these same patients presented a negative correlation between plasma ghrelin levels and total femoral BMD (P=0.03. The present results indicate that ghrelin may be involved in bone metabolism of patients with RA. However, the higher density of ghrelin-producing cells in the gastric mucosa of these patients does not seem to induce a corresponding elevation in the plasma levels of this peptide.

  12. Reward-related genes and personality traits in alcohol-dependent individuals: a pilot case control study.

    Science.gov (United States)

    Landgren, Sara; Berglund, Kristina; Jerlhag, Elisabet; Fahlke, Claudia; Balldin, Jan; Berggren, Ulf; Zetterberg, Henrik; Blennow, Kaj; Engel, Jörgen A

    2011-01-01

    Components of the brain reward system, i.e. the mesolimbic dopamine, laterodorsal cholinergic and ghrelin signaling systems, have been implicated in alcohol reward in preclinical studies. Genetic variants of these systems have previously been linked to alcohol dependence. Here, we genotyped 31 single nucleotide polymorphisms (SNPs): 1 SNP in the dopamine D₂ receptor (DRD2) gene, 20 SNPs in 5 different nicotinic acetylcholine receptor subunit (CHRN*) genes, and 10 SNPs in the genes encoding pro-ghrelin (GHRL) and its receptor (GHSR), in a pilot study of type 1 alcoholics (n = 84) and healthy controls (n = 32). These individuals were characterized using the Temperament and Character Inventory. None of the SNPs were associated with risk of alcohol dependence in this population. The GG genotype of SNP rs13261190 in the CHRNB3 was associated with increased novelty seeking, while SNPs of the ghrelin signaling system were associated with decreased self-directedness (AA of rs495225, GHSR) and alterations in self-transcendence (AA of both rs42451 and rs35680, GHRL). In conclusion, this pilot study suggests that reward-related genes are associated with altered personality scores in type 1 alcohol dependence, which warrants future studies of these associations in larger study samples. Copyright © 2011 S. Karger AG, Basel.

  13. Test of Association Between 10 SNPs in the Oxytocin Receptor Gene and Conduct Disorder

    OpenAIRE

    Sakai, Joseph T.; Crowley, Thomas J.; Stallings, Michael C.; McQueen, Matthew; Hewitt, John K.; Hopfer, Christian; Hoft, Nicole R.; Ehringer, Marissa A.

    2012-01-01

    Animal and human studies have implicated oxytocin (OXT) in affiliative and prosocial behaviors. We tested whether genetic variation in the OXT receptor (OXTR) gene is associated with conduct disorder (CD).

  14. Ghrelin fibers from lateral hypothalamus project to nucleus tractus solitaries and are involved in gastric motility regulation in cisplatin-treated rats.

    Science.gov (United States)

    Gong, Yanling; Liu, Yang; Liu, Fei; Wang, Shasha; Jin, Hong; Guo, Feifei; Xu, Luo

    2017-03-15

    Ghrelin can alleviate cancer chemotherapy-induced dyspepsia in rodents, though the neural mechanisms involved are not known. Therefore, ghrelin projections from the lateral hypothalamus (LH) and its involvement in the regulation of gastric motility in cisplatin-treated rats were investigated with a multi-disciplined approach. Retrograde tracing combined with fluoro-immunohistochemical staining were used to investigate ghrelin fiber projections arising from LH and projecting to nucleus tractus solitaries (NTS). Results revealed that ghrelin fibers originating in LH project to NTS. Expression of ghrelin and its receptor growth hormone secretagogue receptor (GHS-R1a) in LH and NTS were detected by Western Blot. 2days after cisplatin dosing, expression of ghrelin in LH decreased while GHS-R1a in both LH and NTS increased. In electrophysiological experiments, the effects of N-methyl-d-aspartate (NMDA) microinjection in LH on neuronal discharge of gastric distension-responsive neurons in NTS and gastric motility were assessed. NMDA in LH excited most of ghrelin-responsive gastric distension (GD)-sensitive neurons in NTS and promoted gastric motility. This effect was partially blocked by ghrelin antibody in NTS. Furthermore, the excitatory effects of NMDA in cisplatin-treated rats were weaker than those in saline-treated rats. Behaviorally, cisplatin induced a significant increase of kaolin consumption and decrease of food intake. These studies reveal a decreased expression of ghrelin in LH and up-regulation of GHS-R1a in LH and NTS, which are involved in the regulation of GD neuronal discharge in NTS and gastric motility. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Quantitative RT-PCR analysis of estrogen receptor gene expression in laser microdissected prostate cancer tissue.

    Science.gov (United States)

    Walton, Thomas J; Li, Geng; McCulloch, Thomas A; Seth, Rashmi; Powe, Desmond G; Bishop, Michael C; Rees, Robert C

    2009-06-01

    Real-time quantitative RT-PCR analysis of laser microdissected tissue is considered the most accurate technique for determining tissue gene expression. The discovery of estrogen receptor beta (ERbeta) has focussed renewed interest on the role of estrogen receptors in prostate cancer, yet few studies have utilized the technique to analyze estrogen receptor gene expression in prostate cancer. Fresh tissue was obtained from 11 radical prostatectomy specimens and from 6 patients with benign prostate hyperplasia. Pure populations of benign and malignant prostate epithelium were laser microdissected, followed by RNA isolation and electrophoresis. Quantitative RT-PCR was performed using primers for androgen receptor (AR), estrogen receptor beta (ERbeta), estrogen receptor alpha (ERalpha), progesterone receptor (PGR) and prostate specific antigen (PSA), with normalization to two housekeeping genes. Differences in gene expression were analyzed using the Mann-Whitney U-test. Correlation coefficients were analyzed using Spearman's test. Significant positive correlations were seen when AR and AR-dependent PSA, and ERalpha and ERalpha-dependent PGR were compared, indicating a representative population of RNA transcripts. ERbeta gene expression was significantly over-expressed in the cancer group compared with benign controls (P cancer group (P prostate cancer specimens. In concert with recent studies the findings suggest differential production of ERbeta splice variants, which may play important roles in the genesis of prostate cancer. (c) 2009 Wiley-Liss, Inc.

  16. Ghrelin decreases firing activity of gonadotropin-releasing hormone (GnRH neurons in an estrous cycle and endocannabinoid signaling dependent manner.

    Directory of Open Access Journals (Sweden)

    Imre Farkas

    Full Text Available The orexigenic peptide, ghrelin is known to influence function of GnRH neurons, however, the direct effects of the hormone upon these neurons have not been explored, yet. The present study was undertaken to reveal expression of growth hormone secretagogue receptor (GHS-R in GnRH neurons and elucidate the mechanisms of ghrelin actions upon them. Ca(2+-imaging revealed a ghrelin-triggered increase of the Ca(2+-content in GT1-7 neurons kept in a steroid-free medium, which was abolished by GHS-R-antagonist JMV2959 (10 µM suggesting direct action of ghrelin. Estradiol (1nM eliminated the ghrelin-evoked rise of Ca(2+-content, indicating the estradiol dependency of the process. Expression of GHS-R mRNA was then confirmed in GnRH-GFP neurons of transgenic mice by single cell RT-PCR. Firing rate and burst frequency of GnRH-GFP neurons were lower in metestrous than proestrous mice. Ghrelin (40 nM-4 μM administration resulted in a decreased firing rate and burst frequency of GnRH neurons in metestrous, but not in proestrous mice. Ghrelin also decreased the firing rate of GnRH neurons in males. The ghrelin-evoked alterations of the firing parameters were prevented by JMV2959, supporting the receptor-specific actions of ghrelin on GnRH neurons. In metestrous mice, ghrelin decreased the frequency of GABAergic mPSCs in GnRH neurons. Effects of ghrelin were abolished by the cannabinoid receptor type-1 (CB1 antagonist AM251 (1µM and the intracellularly applied DAG-lipase inhibitor THL (10 µM, indicating the involvement of retrograde endocannabinoid signaling. These findings demonstrate that ghrelin exerts direct regulatory effects on GnRH neurons via GHS-R, and modulates the firing of GnRH neurons in an ovarian-cycle and endocannabinoid dependent manner.

  17. Proghrelin peptides: Desacyl ghrelin is a powerful inhibitor of acylated ghrelin, likely to impair physiological effects of acyl ghrelin but not of obestatin A study of pancreatic polypeptide secretion from mouse islets

    DEFF Research Database (Denmark)

    Kumar, Rajesh; Salehi, Albert; Rehfeld, Jens F

    2010-01-01

    Proghrelin, produced by the ghrelin (A-like) cells of the gastric mucosa, gives rise to cleavage products, including desacyl ghrelin, acyl ghrelin and obestatin. The products are thought to be secreted concomitantly. In an earlier study we found acyl ghrelin and obestatin, but not desacyl ghrelin......, to suppress the release of hormones from isolated islets of mouse and rat pancreas....

  18. Proghrelin peptides: Desacyl ghrelin is a powerful inhibitor of acylated ghrelin, likely to impair physiological effects of acyl ghrelin but not of obestatin A study of pancreatic polypeptide secretion from mouse islets

    DEFF Research Database (Denmark)

    Kumar, Rajesh; Salehi, Albert; Rehfeld, Jens F

    2010-01-01

    Proghrelin, produced by the ghrelin (A-like) cells of the gastric mucosa, gives rise to cleavage products, including desacyl ghrelin, acyl ghrelin and obestatin. The products are thought to be secreted concomitantly. In an earlier study we found acyl ghrelin and obestatin, but not desacyl ghrelin...

  19. Cloning of human genes encoding novel G protein-coupled receptors

    Energy Technology Data Exchange (ETDEWEB)

    Marchese, A.; Docherty, J.M.; Heiber, M. [Univ. of Toronto, (Canada)] [and others

    1994-10-01

    We report the isolation and characterization of several novel human genes encoding G protein-coupled receptors. Each of the receptors contained the familiar seven transmembrane topography and most closely resembled peptide binding receptors. Gene GPR1 encoded a receptor protein that is intronless in the coding region and that shared identity (43% in the transmembrane regions) with the opioid receptors. Northern blot analysis revealed that GPR1 transcripts were expressed in the human hippocampus, and the gene was localized to chromosome 15q21.6. Gene GPR2 encoded a protein that most closely resembled an interleukin-8 receptor (51% in the transmembrane regions), and this gene, not expressed in the six brain regions examined, was localized to chromosome 17q2.1-q21.3. A third gene, GPR3, showed identity (56% in the transmembrane regions) with a previously characterized cDNA clone from rat and was localized to chromosome 1p35-p36.1. 31 refs., 5 figs., 1 tab.

  20. Tissue distribution and effects of fasting and obesity on the ghrelin axis in mice.

    Science.gov (United States)

    Morash, Michael G; Gagnon, Jeffrey; Nelson, Stephanie; Anini, Younes

    2010-08-09

    Ghrelin is a 28 amino acid peptide hormone derived from the 117 amino acid proghrelin, following cleavage by proprotein convertase 1 (PC1). In this study, we comprehensively assessed the tissue distribution and the effect of fasting and obesity on preproghrelin, Exon-4D, PC1 and GOAT expression and proghrelin-derived peptide (PGDP) secretion. The stomach was the major source of preproghrelin expression and PDGPs, followed by the small intestine. The remaining peripheral tissues (including the brain and pancreas) contained negligible expression levels. We detected obestatin in all stomach proghrelin cells, however, 22% of proghrelin cells in the small intestine did not express obestatin. There were strain differences in ghrelin secretion in response to fasting between CD1 and C57BL/6 mice. After a 24 hour-fast, CD1 mice had increased plasma levels of total ghrelin and obestatin with no change in preproghrelin mRNA or PGDP tissues levels. C57BL/6 mice showed a different response to a 24 hour-fast having increased proghrelin mRNA expression, stomach acylated ghrelin peptide and no change in plasma obestatin in C57BL/6 mice. In obese mice (ob/ob and diet-induced obesity (DIO)) there was a significant increase in preproghrelin mRNA levels while tissue and plasma PGDP levels were significantly reduced. Fasting did not affect PGDP in obese mice. Obese models displayed differences in GOAT expression, which was elevated in DIO mice, but reduced in ob/ob mice. We did not find co-localization of the leptin receptor in ghrelin expressing stomach cells, ruling out a direct effect of leptin on stomach ghrelin synthesis and secretion. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  1. Ghrelin in the fetal pancreas - a digital quantitation study

    DEFF Research Database (Denmark)

    Hasselby, Jane Preuss; Maroun, Lisa Leth; Federspiel, Birgitte Hartnack

    2012-01-01

    Hasselby JP, Maroun LL, Federspiel BH, Vainer B. Ghrelin in the fetal pancreas - a digital quantitation study. APMIS 2011. Ghrelin is a hormone produced by specialized neuroendocrine cells located in the fetal pancreas. In the adult, ghrelin has multiple effects, but in the fetus the role...... of ghrelin and the distribution of ghrelin-producing cells is not well documented. The aim of this study was to describe and quantitate the number of ghrelin positive cells in the pancreas during gestation. The material consisted of pancreatic tissue from 19 fetuses at different gestational ages...

  2. The axon guidance receptor gene ROBO1 is a candidate gene for developmental dyslexia.

    Directory of Open Access Journals (Sweden)

    Katariina Hannula-Jouppi

    2005-10-01

    Full Text Available Dyslexia, or specific reading disability, is the most common learning disorder with a complex, partially genetic basis, but its biochemical mechanisms remain poorly understood. A locus on Chromosome 3, DYX5, has been linked to dyslexia in one large family and speech-sound disorder in a subset of small families. We found that the axon guidance receptor gene ROBO1, orthologous to the Drosophila roundabout gene, is disrupted by a chromosome translocation in a dyslexic individual. In a large pedigree with 21 dyslexic individuals genetically linked to a specific haplotype of ROBO1 (not found in any other chromosomes in our samples, the expression of ROBO1 from this haplotype was absent or attenuated in affected individuals. Sequencing of ROBO1 in apes revealed multiple coding differences, and the selection pressure was significantly different between the human, chimpanzee, and gorilla branch as compared to orangutan. We also identified novel exons and splice variants of ROBO1 that may explain the apparent phenotypic differences between human and mouse in heterozygous loss of ROBO1. We conclude that dyslexia may be caused by partial haplo-insufficiency for ROBO1 in rare families. Thus, our data suggest that a slight disturbance in neuronal axon crossing across the midline between brain hemispheres, dendrite guidance, or another function of ROBO1 may manifest as a specific reading disability in humans.

  3. The Axon Guidance Receptor Gene ROBO1 Is a Candidate Gene for Developmental Dyslexia.

    Directory of Open Access Journals (Sweden)

    2005-10-01

    Full Text Available Dyslexia, or specific reading disability, is the most common learning disorder with a complex, partially genetic basis, but its biochemical mechanisms remain poorly understood. A locus on Chromosome 3, DYX5, has been linked to dyslexia in one large family and speech-sound disorder in a subset of small families. We found that the axon guidance receptor gene ROBO1, orthologous to the Drosophila roundabout gene, is disrupted by a chromosome translocation in a dyslexic individual. In a large pedigree with 21 dyslexic individuals genetically linked to a specific haplotype of ROBO1 (not found in any other chromosomes in our samples, the expression of ROBO1 from this haplotype was absent or attenuated in affected individuals. Sequencing of ROBO1 in apes revealed multiple coding differences, and the selection pressure was significantly different between the human, chimpanzee, and gorilla branch as compared to orangutan. We also identified novel exons and splice variants of ROBO1 that may explain the apparent phenotypic differences between human and mouse in heterozygous loss of ROBO1. We conclude that dyslexia may be caused by partial haplo-insufficiency for ROBO1 in rare families. Thus, our data suggest that a slight disturbance in neuronal axon crossing across the midline between brain hemispheres, dendrite guidance, or another function of ROBO1 may manifest as a specific reading disability in humans.

  4. Co-regulation of a large and rapidly evolving repertoire of odorant receptor genes

    Directory of Open Access Journals (Sweden)

    Lane Robert P

    2007-09-01

    Full Text Available Abstract The olfactory system meets niche- and species-specific demands by an accelerated evolution of its odorant receptor repertoires. In this review, we describe evolutionary processes that have shaped olfactory and vomeronasal receptor gene families in vertebrate genomes. We emphasize three important periods in the evolution of the olfactory system evident by comparative genomics: the adaptation to land in amphibian ancestors, the decline of olfaction in primates, and the delineation of putative pheromone receptors concurrent with rodent speciation. The rapid evolution of odorant receptor genes, the sheer size of the repertoire, as well as their wide distribution in the genome, presents a developmental challenge: how are these ever-changing odorant receptor repertoires coordinated within the olfactory system? A central organizing principle in olfaction is the specialization of sensory neurons resulting from each sensory neuron expressing only ~one odorant receptor allele. In this review, we also discuss this mutually exclusive expression of odorant receptor genes. We have considered several models to account for co-regulation of odorant receptor repertoires, as well as discussed a new hypothesis that invokes important epigenetic properties of the system.

  5. Cloning of the cDNA and gene for a human D2 dopamine receptor

    International Nuclear Information System (INIS)

    Grady, D.K.; Makam, H.; Stofko, R.E.; Bunzow, J.R.; Civelli, O.; Marchionni, M.A.; Alfano, M.; Frothingham, L.; Fischer, J.B.; Burke-Howie, K.J.; Server, A.C.

    1989-01-01

    A clone encoding a human D 2 dopamine receptor was isolated from a pituitary cDNA library and sequenced. The deduced protein sequence is 96% identical with that of the cloned rat receptor with one major difference: the human receptor contains an additional 29 amino acids in its putative third cytoplasmic loop. Southern blotting demonstrated the presence of only one human D 2 receptor gene. Two overlapping phage containing the gene were isolated and characterized. DNA sequence analysis of these clones showed that the coding sequence is interrupted by six introns and that the additional amino acids present in the human pituitary receptor are encoded by a single exon of 87 base pairs. The involvement of this sequence in alternative splicing and its biological significance are discussed

  6. A natural variant of obestatin, Q90L, inhibits ghrelin's action on food intake and GH secretion and targets NPY and GHRH neurons in mice.

    Directory of Open Access Journals (Sweden)

    Rim Hassouna

    Full Text Available BACKGROUND: Ghrelin and obestatin are two gut-derived peptides originating from the same ghrelin/obestatin prepropeptide gene (GHRL. While ghrelin stimulates growth hormone (GH secretion and food intake and inhibits γ-aminobutyric-acid synaptic transmission onto GHRH (Growth Hormone Releasing Hormone neurons, obestatin blocks these effects. In Humans, GHRL gene polymorphisms have been associated with pathologies linked to an unbalanced energy homeostasis. We hypothesized that one polymorphism located in the obestatin sequence (Q to L substitution in position 90 of the ghrelin/obestatin prepropeptide, rs4684677 may impact on the function of obestatin. In the present study, we tested the activity of native and Q90L obestatin to modulate ghrelin-induced food intake, GH secretion, cFos activity in GHRH and Neuropeptide Y (NPY neurons and γ-aminobutyric-acid activity onto GHRH neurons. METHODOLOGY/PRINCIPAL FINDINGS: Food intake, GH secretion and electrophysiological recordings were assessed in C57BL/6 mice. cFos activity was measured in NPY-Renilla-GFP and GHRH-eGFP mice. Mice received saline, ghrelin or ghrelin combined to native or Q90L obestatin (30 nmol each in the early light phase. Ghrelin stimulation of food intake and GH secretion varied considerably among individual mice with 59-77% eliciting a robust response. In these high-responders, ghrelin-induced food intake and GH secretion were reduced equally by native and Q90L obestatin. In contrast to in vivo observations, Q90L was slightly more efficient than native obestatin in inhibiting ghrelin-induced cFos activation within the hypothalamic arcuate nucleus and the nucleus tractus solitarius of the brainstem. After ghrelin injection, 26% of NPY neurons in the arcuate nucleus expressed cFos protein and this number was significantly reduced by co-administration of Q90L obestatin. Q90L was also more potent that native obestatin in reducing ghrelin-induced inhibition of

  7. A natural variant of obestatin, Q90L, inhibits ghrelin's action on food intake and GH secretion and targets NPY and GHRH neurons in mice.

    Science.gov (United States)

    Hassouna, Rim; Zizzari, Philippe; Viltart, Odile; Yang, Seung-Kwon; Gardette, Robert; Videau, Catherine; Badoer, Emilio; Epelbaum, Jacques; Tolle, Virginie

    2012-01-01

    Ghrelin and obestatin are two gut-derived peptides originating from the same ghrelin/obestatin prepropeptide gene (GHRL). While ghrelin stimulates growth hormone (GH) secretion and food intake and inhibits γ-aminobutyric-acid synaptic transmission onto GHRH (Growth Hormone Releasing Hormone) neurons, obestatin blocks these effects. In Humans, GHRL gene polymorphisms have been associated with pathologies linked to an unbalanced energy homeostasis. We hypothesized that one polymorphism located in the obestatin sequence (Q to L substitution in position 90 of the ghrelin/obestatin prepropeptide, rs4684677) may impact on the function of obestatin. In the present study, we tested the activity of native and Q90L obestatin to modulate ghrelin-induced food intake, GH secretion, cFos activity in GHRH and Neuropeptide Y (NPY) neurons and γ-aminobutyric-acid activity onto GHRH neurons. Food intake, GH secretion and electrophysiological recordings were assessed in C57BL/6 mice. cFos activity was measured in NPY-Renilla-GFP and GHRH-eGFP mice. Mice received saline, ghrelin or ghrelin combined to native or Q90L obestatin (30 nmol each) in the early light phase. Ghrelin stimulation of food intake and GH secretion varied considerably among individual mice with 59-77% eliciting a robust response. In these high-responders, ghrelin-induced food intake and GH secretion were reduced equally by native and Q90L obestatin. In contrast to in vivo observations, Q90L was slightly more efficient than native obestatin in inhibiting ghrelin-induced cFos activation within the hypothalamic arcuate nucleus and the nucleus tractus solitarius of the brainstem. After ghrelin injection, 26% of NPY neurons in the arcuate nucleus expressed cFos protein and this number was significantly reduced by co-administration of Q90L obestatin. Q90L was also more potent that native obestatin in reducing ghrelin-induced inhibition of γ-aminobutyric-acid synaptic transmission onto GHRH neurons. These data support

  8. A Natural Variant of Obestatin, Q90L, Inhibits Ghrelin's Action on Food Intake and GH Secretion and Targets NPY and GHRH Neurons in Mice

    Science.gov (United States)

    Hassouna, Rim; Zizzari, Philippe; Viltart, Odile; Yang, Seung-Kwon; Gardette, Robert; Videau, Catherine; Badoer, Emilio; Epelbaum, Jacques; Tolle, Virginie

    2012-01-01

    Background Ghrelin and obestatin are two gut-derived peptides originating from the same ghrelin/obestatin prepropeptide gene (GHRL). While ghrelin stimulates growth hormone (GH) secretion and food intake and inhibits γ-aminobutyric-acid synaptic transmission onto GHRH (Growth Hormone Releasing Hormone) neurons, obestatin blocks these effects. In Humans, GHRL gene polymorphisms have been associated with pathologies linked to an unbalanced energy homeostasis. We hypothesized that one polymorphism located in the obestatin sequence (Q to L substitution in position 90 of the ghrelin/obestatin prepropeptide, rs4684677) may impact on the function of obestatin. In the present study, we tested the activity of native and Q90L obestatin to modulate ghrelin-induced food intake, GH secretion, cFos activity in GHRH and Neuropeptide Y (NPY) neurons and γ-aminobutyric-acid activity onto GHRH neurons. Methodology/Principal findings Food intake, GH secretion and electrophysiological recordings were assessed in C57BL/6 mice. cFos activity was measured in NPY-Renilla-GFP and GHRH-eGFP mice. Mice received saline, ghrelin or ghrelin combined to native or Q90L obestatin (30 nmol each) in the early light phase. Ghrelin stimulation of food intake and GH secretion varied considerably among individual mice with 59–77% eliciting a robust response. In these high-responders, ghrelin-induced food intake and GH secretion were reduced equally by native and Q90L obestatin. In contrast to in vivo observations, Q90L was slightly more efficient than native obestatin in inhibiting ghrelin-induced cFos activation within the hypothalamic arcuate nucleus and the nucleus tractus solitarius of the brainstem. After ghrelin injection, 26% of NPY neurons in the arcuate nucleus expressed cFos protein and this number was significantly reduced by co-administration of Q90L obestatin. Q90L was also more potent that native obestatin in reducing ghrelin-induced inhibition of γ-aminobutyric-acid synaptic

  9. Changes in gene expression following androgen receptor blockade ...

    Indian Academy of Sciences (India)

    Madhu urs

    of gene expression in the ventral prostate, it is not clear whether all the gene expression ... These include clusterin, methionine adenosyl transferase IIα, and prostate-specific ..... MAGEE1 melanoma antigen and no similarity was found with the ...

  10. Metabolic aspects of the ghrelin system: Role of acylated and unacylated ghrelin in glucose homeostasis

    NARCIS (Netherlands)

    C. Gauna (Carlotta)

    2007-01-01

    textabstractIn the last decade the discovery of ghrelin, a gut peptide discovered in 1999 by Kojima and colleagues (1), has led to the identification of a complex system that introduced new perspectives in neuroendocrine and metabolic research. Ghrelin is a peptide-hormone of 28 amino acids,

  11. No linkage and association of atopy to chromosome 16 including the interleukin-4 receptor gene

    DEFF Research Database (Denmark)

    Haagerup, A; Bjerke, T; Schiøtz, P O

    2001-01-01

    BACKGROUND: Several susceptibility genes for atopy have been suggested in recent years. Few have been investigated as intensively as the interleukin-4-receptor alpha (IL4Ralpha) gene on chromosome 16. The results remain in dispute. Therefore, in a robust design, we tested for association of type ...

  12. Mutation screening of the Ectodysplasin-A receptor gene EDAR in hypohidrotic ectodermal dysplasia

    NARCIS (Netherlands)

    van der Hout, Annemarie H.; Oudesluijs, Gretel G.; Venema, Andrea; Verheij, Joke B. G. M.; Mol, Bart G. J.; Rump, Patrick; Brunner, Han G.; Vos, Yvonne J.; van Essen, Anthonie J.

    Hypohidrotic ectodermal dysplasia (HED) can be caused by mutations in the X-linked ectodysplasin A (ED1) gene or the autosomal ectodysplasin A-receptor (EDAR) and EDAR-associated death domain (EDARADD) genes. X-linked and autosomal forms are sometimes clinically indistinguishable. For genetic

  13. Gene number determination and genetic polymorphism of the gamma delta T cell co-receptor WC1 genes

    Directory of Open Access Journals (Sweden)

    Chen Chuang

    2012-10-01

    Full Text Available Abstract Background WC1 co-receptors belong to the scavenger receptor cysteine-rich (SRCR superfamily and are encoded by a multi-gene family. Expression of particular WC1 genes defines functional subpopulations of WC1+ γδ T cells. We have previously identified partial or complete genomic sequences for thirteen different WC1 genes through annotation of the bovine genome Btau_3.1 build. We also identified two WC1 cDNA sequences from other cattle that did not correspond to sequences in the Btau_3.1 build. Their absence in the Btau_3.1 build may have reflected gaps in the genome assembly or polymorphisms among animals. Since the response of γδ T cells to bacterial challenge is determined by WC1 gene expression, it was critical to understand whether individual cattle or breeds differ in the number of WC1 genes or display polymorphisms. Results Real-time quantitative PCR using DNA from the animal whose genome was sequenced (“Dominette” and sixteen other animals representing ten breeds of cattle, showed that the number of genes coding for WC1 co-receptors is thirteen. The complete coding sequences of those thirteen WC1 genes is presented, including the correction of an error in the WC1-2 gene due to mis-assembly in the Btau_3.1 build. All other cDNA sequences were found to agree with the previous annotation of complete or partial WC1 genes. PCR amplification and sequencing of the most variable N-terminal SRCR domain (domain 1 which has the SRCR “a” pattern of each of the thirteen WC1 genes showed that the sequences are highly conserved among individuals and breeds. Of 160 sequences of domain 1 from three breeds of cattle, no additional sequences beyond the thirteen described WC1 genes were found. Analysis of the complete WC1 cDNA sequences indicated that the thirteen WC1 genes code for three distinct WC1 molecular forms. Conclusion The bovine WC1 multi-gene family is composed of thirteen genes coding for three structural forms whose

  14. PET/CT imaging of human somatostatin receptor 2 (hsstr2) as reporter gene for gene therapy

    International Nuclear Information System (INIS)

    Hofmann, M.; Gazdhar, A.; Weitzel, T.; Schmid, R.; Krause, T.

    2006-01-01

    Localized information on region-selective gene expression in small animals is widely obtained by use of reporter genes inducing light emission. Using these reporter genes for imaging deep inside the human body fluorescent probes are hindered by attenuation, scattering and possible fluorescence quenching. This can be overcome by use of radio-peptide receptors as reporter genes. Therefore, the feasibility of the somatostatin receptor 2 expression vector system for expression imaging was checked against a control vector containing luciferase gene. For in vivo transduction of vector DNA into the rat forelimb muscles the in vivo electroporation technique was chosen because of its high regio-selectivity. The gene expression was imaged by high-sensitive CCD camera (luciferase activity) and by PET/CT using a Ga-68-DOTATOC as radio peptide probe. The relative sstr2 expression was enhanced by gene transduction at maximum to a factor of 15. The PET/CT images could be fully quantified. The above demonstrated feasibility of radio-peptide PET/CT reporter gene imaging may serve in the future as a tool for full quantitative understanding of regional gene expression, especially in large animals and humans

  15. PET/CT imaging of human somatostatin receptor 2 (hsstr2) as reporter gene for gene therapy

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, M. [Molecular Imaging and Therapy Group (MIT-Bern), Clinic of Nuclear Medicine, Inselspital, Medical School Bern (Switzerland)]. E-mail: Michael.Hofmann@insel.ch; Gazdhar, A. [Division of Pulmonary Medicine, University Hospital Bern (Switzerland); Weitzel, T. [Molecular Imaging and Therapy Group (MIT-Bern), Clinic of Nuclear Medicine, Inselspital, Medical School Bern (Switzerland); Schmid, R. [Division of Thoracic Surgery, University Hospital Bern (Switzerland); Krause, T. [Molecular Imaging and Therapy Group (MIT-Bern), Clinic of Nuclear Medicine, Inselspital, Medical School Bern (Switzerland)

    2006-12-20

    Localized information on region-selective gene expression in small animals is widely obtained by use of reporter genes inducing light emission. Using these reporter genes for imaging deep inside the human body fluorescent probes are hindered by attenuation, scattering and possible fluorescence quenching. This can be overcome by use of radio-peptide receptors as reporter genes. Therefore, the feasibility of the somatostatin receptor 2 expression vector system for expression imaging was checked against a control vector containing luciferase gene. For in vivo transduction of vector DNA into the rat forelimb muscles the in vivo electroporation technique was chosen because of its high regio-selectivity. The gene expression was imaged by high-sensitive CCD camera (luciferase activity) and by PET/CT using a Ga-68-DOTATOC as radio peptide probe. The relative sstr2 expression was enhanced by gene transduction at maximum to a factor of 15. The PET/CT images could be fully quantified. The above demonstrated feasibility of radio-peptide PET/CT reporter gene imaging may serve in the future as a tool for full quantitative understanding of regional gene expression, especially in large animals and human000.

  16. Ghrelin protects against depleted uranium-induced apoptosis of MC3T3-E1 cells through oxidative stress-mediated p38-mitogen-activated protein kinase pathway

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Yuhui; Liu, Cong; Huang, Jiawei; Gu, Ying; Li, Hong; Yang, Zhangyou; Liu, Jing [State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Combined Injury, Chongqing Engineering Research Center for Nanomedicine, College of Preventive Medicine, Third Military Medical University, No. 30 Gaotanyan Street, Shapingba District, Chongqing 400038 (China); Wang, Weidong, E-mail: wwdwyl@sina.com [Department of Radiation Oncology, Shanghai Jiao Tong University Affiliated Sixth People Hospital, Shanghai 200233 (China); Li, Rong, E-mail: yuhui_hao@126.com [State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Combined Injury, Chongqing Engineering Research Center for Nanomedicine, College of Preventive Medicine, Third Military Medical University, No. 30 Gaotanyan Street, Shapingba District, Chongqing 400038 (China)

    2016-01-01

    Depleted uranium (DU) mainly accumulates in the bone over the long term. Osteoblast cells are responsible for the formation of bone, and they are sensitive to DU damage. However, studies investigating methods of reducing DU damage in osteoblasts are rarely reported. Ghrelin is a stomach hormone that stimulates growth hormones released from the hypothalamic–pituitary axis, and it is believed to play an important physiological role in bone metabolism. This study evaluates the impact of ghrelin on DU-induced apoptosis of the osteoblast MC3T3-E1 and investigates its underlying mechanisms. The results show that ghrelin relieved the intracellular oxidative stress induced by DU, eliminated reactive oxygen species (ROS) and reduced lipid peroxidation by increasing intracellular GSH levels; in addition, ghrelin effectively suppressed apoptosis, enhanced mitochondrial membrane potential, and inhibited cytochrome c release and caspase-3 activation after DU exposure. Moreover, ghrelin significantly reduced the expression of DU-induced phosphorylated p38-mitogen-activated protein kinase (MAPK). A specific inhibitor (SB203580) or specific siRNA of p38-MAPK could significantly suppress DU-induced apoptosis and related signals, whereas ROS production was not affected. In addition, ghrelin receptor inhibition could reduce the anti-apoptosis effect of ghrelin on DU and reverse the effect of ghrelin on intracellular ROS and p38-MAPK after DU exposure. These results suggest that ghrelin can suppress DU-induced apoptosis of MC3T3-E1 cells, reduce DU-induced oxidative stress by interacting with its receptor, and inhibit downstream p38-MAPK activation, thereby suppressing the mitochondrial-dependent apoptosis pathway. - Highlights: • Ghrelin suppressed DU-induced apoptosis of MC3T3-E1 cells. • Ghrelin inhibited DU-induced oxidative stress and further p38-MAPK activation. • Ghrelin further suppressed mitochondrial-dependent apoptosis pathway. • The anti-oxidation effect of

  17. Effects of gastric emptying on the postprandial ghrelin response

    NARCIS (Netherlands)

    Blom, W.A.M.; Lluch, A.; Vinoy, S.; Stafleu, A.; Berg, van den R.; Holst, J.J.; Kok, F.J.; Hendriks, H.F.J.

    2006-01-01

    Distension and chemosensitization of the stomach are insufficient to induce a ghrelin response, suggesting that postgastric feedback is required. This postgastric feedback may be regulated through insulin. We investigated the relation between gastric emptying rate and the postprandial ghrelin

  18. Investigation of Gamma-aminobutyric acid (GABA A receptors genes and migraine susceptibility

    Directory of Open Access Journals (Sweden)

    Ciccodicola Alfredo

    2008-12-01

    Full Text Available Abstract Background Migraine is a neurological disorder characterized by recurrent attacks of severe headache, affecting around 12% of Caucasian populations. It is well known that migraine has a strong genetic component, although the number and type of genes involved is still unclear. Prior linkage studies have reported mapping of a migraine gene to chromosome Xq 24–28, a region containing a cluster of genes for GABA A receptors (GABRE, GABRA3, GABRQ, which are potential candidate genes for migraine. The GABA neurotransmitter has been implicated in migraine pathophysiology previously; however its exact role has not yet been established, although GABA receptors agonists have been the target of therapeutic developments. The aim of the present research is to investigate the role of the potential candidate genes reported on chromosome Xq 24–28 region in migraine susceptibility. In this study, we have focused on the subunit GABA A receptors type ε (GABRE and type θ (GABRQ genes and their involvement in migraine. Methods We have performed an association analysis in a large population of case-controls (275 unrelated Caucasian migraineurs versus 275 controls examining a set of 3 single nucleotide polymorphisms (SNPs in the coding region (exons 3, 5 and 9 of the GABRE gene and also the I478F coding variant of the GABRQ gene. Results Our study did not show any association between the examined SNPs in our test population (P > 0.05. Conclusion Although these particular GABA receptor genes did not show positive association, further studies are necessary to consider the role of other GABA receptor genes in migraine susceptibility.

  19. High-throughput Microarray Detection of Vomeronasal Receptor Gene Expression in Rodents

    Directory of Open Access Journals (Sweden)

    Xiaohong Zhang

    2010-11-01

    Full Text Available We performed comprehensive data mining to explore the vomeronasal receptor (V1R & V2R repertoires in mouse and rat using the mm5 and rn3 genome, respectively. This bioinformatic analysis was followed by investigation of gene expression using a custom designed high-density oligonucleotide array containing all of these receptors and other selected genes of interest. This array enabled us to detect the specific expression of V1R and V2Rs which were previously identified solely based on computational prediction from gene sequence data, thereby establishing that these genes are indeed part of the vomeronasal system, especially the V2Rs. 168 V1Rs and 98 V2Rs were detected to be highly enriched in mouse vomeronasal organ (VNO, and 108 V1Rs and 87 V2Rs in rat VNO. We monitored the expression profile of mouse VR genes in other non-VNO tissues with the result that some VR genes were re-designated as VR-like genes based on their non-olfactory expression pattern. Temporal expression profiles for mouse VR genes were characterized and their patterns were classified, revealing the developmental dynamics of these so-called pheromone receptors. We found numerous patterns of temporal expression which indicate possible behavior-related functions. The uneven composition of VR genes in certain patterns suggests a functional differentiation between the two types of VR genes. We found the coherence between VR genes and transcription factors in terms of their temporal expression patterns. In situ hybridization experiments were performed to evaluate the cell number change over time for selected receptor genes.

  20. Development of gene diagnosis for diabetes and cholecystitis based on gene analysis of CCK-A receptor

    International Nuclear Information System (INIS)

    Kono, Akira

    1999-01-01

    Base sequence analysis of CCKAR gene (a gene of A-type receptor for cholecystokinin) from OLETF rat, a model rat for insulin-independent diabetes was made based on the base sequence of wild CCKAR gene, which had been clarified in the previous year. From the pancreas of OLETF rat, DNA was extracted and transduced into λphage after fragmentation to construct the gene library of OLETF. Then, λphage DNA clone bound with labelled cDNA of CCKAR gene was analyzed and the gene structure was compared with that of the wild gene. It was demonstrated that CCKAR gene of OLETF had a deletion (6800 b.p.) ranging from the promoter region to the Exon 2, suggesting that CCKAR gene is not functional in OLETF rat. The whole sequence of this mutant gene was registered into Japan DNA Bank (D 50610). Then, F 2 offspring rats were obtained through crossing OLETF (female) and F344 (male) and the time course-changes in the blood glucose level after glucose loading were compared among them. The blood glucose level after glucose loading was significantly higher in the homo-mutant F 2 (CCKAR,-/-) as well as the parent OLETF rat than hetero-mutant F 2 (CCKARm-/+) or the wild rat (CCKAR,+/+). This suggests that CCKAR gene might be involved in the control of blood glucose level and an alteration of the expression level or the functions of CCKAR gene might affect the blood glucose level. (M.N.)

  1. Sickness behaviour after lipopolysaccharide treatment in ghrelin deficient mice

    OpenAIRE

    Szentirmai, Éva; Krueger, James M.

    2013-01-01

    Ghrelin is an orexigenic hormone produced mainly by the gastrointestinal system and the brain. Much evidence also indicates a role for ghrelin in sleep and thermoregulation. Further, ghrelin was recently implicated in immune system modulation. Administration of bacterial lipopolysaccharide (LPS) induces fever, anorexia, and increased non-rapid-eye movement sleep (NREMS) and these actions are mediated primarily by proinflammatory cytokines. Ghrelin reduces LPS-induced fever, ...

  2. Changes in subcellular distribution of n-octanoyl or n-decanoyl ghrelin in ghrelin-producing cells

    Directory of Open Access Journals (Sweden)

    Yoshihiro eNishi

    2013-07-01

    Full Text Available Background: The enzyme ghrelin O-acyltransferase (GOAT catalyzes the acylation of ghrelin. The molecular form of GOAT, together with its reaction in vitro, has been reported previously. However, the sub-cellular processes governing the acylation of ghrelin remain to be elucidated.Methods: Double immunoelectron microscopy was used to examine changes in the relative proportions of secretory granules containing n-octanoyl ghrelin (C8-ghrelin or n-decanoyl ghrelin (C10-ghrelin in ghrelin-producing cells of mouse stomachs. The dynamics of C8-type (possessing C8-ghrelin exclusively, C10-type (possessing C10-ghrelin only and mixed-type secretory granules (possessing both C8- and C10-ghrelin were investigated after fasting for 48h or after two weeks’ feeding with chow containing glyceryl-tri-octanoate (C8-MCT or glyceryl-tri-decanoate (C10-MCT. The dynamics of C8- or C10-ghrelin immunoreactivity (ir-C8- or ir-C10-ghrelin within the mixed-type granules were also investigated.Results: Immunoelectron microscopic analysis revealed the co-existence of C8- and C10-ghrelin within the same secretory granules (mixed-type in ghrelin-producing cells. Compared to control mice fed standard chow, the ratio of C10-type secretory granules increased significantly after ingestion of C10-MCT, whereas that of C8-type granules declined significantly under the same treatment. After ingestion of C8-MCT, the proportion of C8-type secretory granules increased significantly. Within the mixed-type granules the ratio of ir-C10-ghrelin increased significantly and that of ir-C8-ghrelin decreased significantly upon fasting. Conclusions: These findings confirmed that C10-ghrelin, another acyl-form of active ghrelin, is stored within the same secretory granules as C8-ghrelin, and suggested that the types of medium-chain acyl-molecules surrounding and available to the ghrelin-GOAT system may affect the physiological processes of ghrelin acylation.

  3. Changes in Subcellular Distribution of n-Octanoyl or n-Decanoyl Ghrelin in Ghrelin-Producing Cells

    Science.gov (United States)

    Nishi, Yoshihiro; Mifune, Hiroharu; Yabuki, Akira; Tajiri, Yuji; Hirata, Rumiko; Tanaka, Eiichiro; Hosoda, Hiroshi; Kangawa, Kenji; Kojima, Masayasu

    2013-01-01

    Background: The enzyme ghrelin O-acyltransferase (GOAT) catalyzes the acylation of ghrelin. The molecular form of GOAT, together with its reaction in vitro, has been reported previously. However, the subcellular processes governing the acylation of ghrelin remain to be elucidated. Methods: Double immunoelectron microscopy was used to examine changes in the relative proportions of secretory granules containing n-octanoyl ghrelin (C8-ghrelin) or n-decanoyl ghrelin (C10-ghrelin) in ghrelin-producing cells of mouse stomachs. The dynamics of C8-type (possessing C8-ghrelin exclusively), C10-type (possessing C10-ghrelin only), and mixed-type secretory granules (possessing both C8- and C10-ghrelin) were investigated after fasting for 48 h or after 2 weeks feeding with chow containing glyceryl-tri-octanoate (C8-MCT) or glyceryl-tri-decanoate (C10-MCT). The dynamics of C8- or C10-ghrelin-immunoreactivity (ir-C8- or ir-C10-ghrelin) within the mixed-type granules were also investigated. Results: Immunoelectron microscopic analysis revealed the co-existence of C8- and C10-ghrelin within the same secretory granules (mixed-type) in ghrelin-producing cells. Compared to control mice fed standard chow, the ratio of C10-type secretory granules increased significantly after ingestion of C10-MCT, whereas that of C8-type granules declined significantly under the same treatment. After ingestion of C8-MCT, the proportion of C8-type secretory granules increased significantly. Within the mixed-type granules the ratio of ir-C10-ghrelin increased significantly and that of ir-C8-ghrelin decreased significantly upon fasting. Conclusion: These findings confirmed that C10-ghrelin, another acyl-form of active ghrelin, is stored within the same secretory granules as C8-ghrelin, and suggested that the types of medium-chain acyl-molecules surrounding and available to the ghrelin-GOAT system may affect the physiological processes of ghrelin acylation. PMID:23847595

  4. Natural killer cell receptor genes in the family Equidae: not only Ly49.

    Directory of Open Access Journals (Sweden)

    Jan Futas

    Full Text Available Natural killer (NK cells have important functions in immunity. NK recognition in mammals can be mediated through killer cell immunoglobulin-like receptors (KIR and/or killer cell lectin-like Ly49 receptors. Genes encoding highly variable NK cell receptors (NKR represent rapidly evolving genomic regions. No single conservative model of NKR genes was observed in mammals. Single-copy low polymorphic NKR genes present in one mammalian species may expand into highly polymorphic multigene families in other species. In contrast to other non-rodent mammals, multiple Ly49-like genes appear to exist in the horse, while no functional KIR genes were observed in this species. In this study, Ly49 and KIR were sought and their evolution was characterized in the entire family Equidae. Genomic sequences retrieved showed the presence of at least five highly conserved polymorphic Ly49 genes in horses, asses and zebras. These findings confirmed that the expansion of Ly49 occurred in the entire family. Several KIR-like sequences were also identified in the genome of Equids. Besides a previously identified non-functional KIR-Immunoglobulin-like transcript fusion gene (KIR-ILTA and two putative pseudogenes, a KIR3DL-like sequence was analyzed. In contrast to previous observations made in the horse, the KIR3DL sequence, genomic organization and mRNA expression suggest that all Equids might produce a functional KIR receptor protein molecule with a single non-mutated immune tyrosine-based inhibition motif (ITIM domain. No evidence for positive selection in the KIR3DL gene was found. Phylogenetic analysis including rhinoceros and tapir genomic DNA and deduced amino acid KIR-related sequences showed differences between families and even between species within the order Perissodactyla. The results suggest that the order Perissodactyla and its family Equidae with expanded Ly49 genes and with a potentially functional KIR gene may represent an interesting model for

  5. Natural Killer Cell Receptor Genes in the Family Equidae: Not only Ly49

    Science.gov (United States)

    Futas, Jan; Horin, Petr

    2013-01-01

    Natural killer (NK) cells have important functions in immunity. NK recognition in mammals can be mediated through killer cell immunoglobulin-like receptors (KIR) and/or killer cell lectin-like Ly49 receptors. Genes encoding highly variable NK cell receptors (NKR) represent rapidly evolving genomic regions. No single conservative model of NKR genes was observed in mammals. Single-copy low polymorphic NKR genes present in one mammalian species may expand into highly polymorphic multigene families in other species. In contrast to other non-rodent mammals, multiple Ly49-like genes appear to exist in the horse, while no functional KIR genes were observed in this species. In this study, Ly49 and KIR were sought and their evolution was characterized in the entire family Equidae. Genomic sequences retrieved showed the presence of at least five highly conserved polymorphic Ly49 genes in horses, asses and zebras. These findings confirmed that the expansion of Ly49 occurred in the entire family. Several KIR-like sequences were also identified in the genome of Equids. Besides a previously identified non-functional KIR-Immunoglobulin-like transcript fusion gene (KIR-ILTA) and two putative pseudogenes, a KIR3DL-like sequence was analyzed. In contrast to previous observations made in the horse, the KIR3DL sequence, genomic organization and mRNA expression suggest that all Equids might produce a functional KIR receptor protein molecule with a single non-mutated immune tyrosine-based inhibition motif (ITIM) domain. No evidence for positive selection in the KIR3DL gene was found. Phylogenetic analysis including rhinoceros and tapir genomic DNA and deduced amino acid KIR-related sequences showed differences between families and even between species within the order Perissodactyla. The results suggest that the order Perissodactyla and its family Equidae with expanded Ly49 genes and with a potentially functional KIR gene may represent an interesting model for evolutionary biology of

  6. Ghrelin gene polymorphism in dairy cattle

    OpenAIRE

    KOWALEWSKA-ŁUCZAK, Inga; SZEMBEK, Maria; KULIG, Hanna

    2012-01-01

    The aim of this experiment was to estimate possible associations between GHRL G375A genotypes and some milk performance traits (yields of milk, protein and fat, and protein and fat content). The study included Polish Holstein–Friesian strain Red-and-White cows. The ACRS and PCR-RFLP method was used to identification genotypes. GHRL G375A frequencies were as follow: AA – 0.86, AG- 0.14, and GG – was not found, while allele frequencies were: A – 0.93 and G – 0.07. In this study, no statisticall...

  7. Ghrelin gene polymorphism in dairy cattle

    Directory of Open Access Journals (Sweden)

    Inga KOWALEWSKA-ŁUCZAK

    2012-01-01

    Full Text Available The aim of this experiment was to estimate possible associations between GHRL G375A genotypes and some milk performance traits (yields of milk, protein and fat, and protein and fat content. The study included Polish Holstein–Friesian strain Red-and-White cows. The ACRS and PCR-RFLP method was used to identification genotypes. GHRL G375A frequencies were as follow: AA – 0.86, AG- 0.14, and GG – was not found, while allele frequencies were: A – 0.93 and G – 0.07. In this study, no statistically significant correlation between GHRL genotypes and analyzed traits was found, however, a tendency to maintain a relationship of genotypes with milk production traits is shown.

  8. Nicotine enhances modulation of food-cue reactivity by leptin and ghrelin in the ventromedial prefrontal cortex.

    Science.gov (United States)

    Kroemer, Nils B; Wuttig, Franziska; Bidlingmaier, Martin; Zimmermann, Ulrich S; Smolka, Michael N

    2015-07-01

    Endocrine signals such as ghrelin and leptin are known to modulate the mesocorticolimbic dopaminergic system and, consequently, show associations with food and drug reward. In animal models, nicotine was demonstrated to reduce bod