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Sample records for resistance insulin secretion

  1. Studies on insulin secretion and insulin resistance in non-insulin-dependent diabetes in young Indians

    International Nuclear Information System (INIS)

    Naidoo, C.

    1986-01-01

    Patients with Non-insulin-dependent diabetes mellitus (NIDDM) have defects in insulin secretion and insulin action. In the discrete genetic syndrome of NIDDY (non-insulin-dependent diabetes in the young), the situation is less clear and these aspects is the subject of this thesis. This study included Indian pasients with three generation transmission of NIDDM via one parent. The insulin and C-peptide responses to oral and intravenous glucose in patients with NIDDY were studied. The insulin and glucose responses to non-glucose secretogogues glucagon, tolbutamide and arginine, in NIDDY were also investigated. The following aspects with regard to insulin resistance in NIDDY were examined: glucose and free fatty acid response to intravenous insulin administration, insulin binding to circulating erythrocytes and monocytes, 125 I-insulin binding to the solubilized erythrocyte membrane receptor and 125 I-insulin binding to fibroblasts in culture

  2. Studies on insulin secretion and insulin resistance in non-insulin-dependent diabetes in young Indians

    Energy Technology Data Exchange (ETDEWEB)

    Naidoo, C

    1986-01-01

    Patients with Non-insulin-dependent diabetes mellitus (NIDDM) have defects in insulin secretion and insulin action. In the discrete genetic syndrome of NIDDY (non-insulin-dependent diabetes in the young), the situation is less clear and these aspects is the subject of this thesis. This study included Indian pasients with three generation transmission of NIDDM via one parent. The insulin and C-peptide responses to oral and intravenous glucose in patients with NIDDY were studied. The insulin and glucose responses to non-glucose secretogogues glucagon, tolbutamide and arginine, in NIDDY were also investigated. The following aspects with regard to insulin resistance in NIDDY were examined: glucose and free fatty acid response to intravenous insulin administration, insulin binding to circulating erythrocytes and monocytes, /sup 125/I-insulin binding to the solubilized erythrocyte membrane receptor and /sup 125/I-insulin binding to fibroblasts in culture.

  3. Macrophage-secreted factors induce adipocyte inflammation and insulin resistance

    International Nuclear Information System (INIS)

    Permana, Paska A.; Menge, Christopher; Reaven, Peter D.

    2006-01-01

    Macrophage infiltration into adipose tissue increases with obesity, a condition associated with low-grade inflammation and insulin resistance. We investigated the direct effects of macrophage-secreted factors on adipocyte inflammation and insulin resistance. 3T3-L1 adipocytes incubated with media conditioned by RAW264.7 macrophages (RAW-CM) showed dramatically increased transcription of several inflammation-related genes, greater nuclear factor kappa B (NF-κB) activity, and enhanced binding of U937 monocytes. All of these effects were prevented by co-incubation with pyrrolidinedithiocarbamate, an NF-κB inhibitor. Adipocytes incubated with RAW-CM also released more non-esterified fatty acids and this increased lipolysis was not suppressed by insulin. In addition, RAW-CM treatment decreased insulin-stimulated glucose uptake in adipocytes. Taken together, these results indicate that macrophage-secreted factors induce inflammatory responses and reduce insulin responsiveness in adipocytes. These effects of macrophage-secreted factors on adipocytes may contribute significantly to the systemic inflammation and insulin resistance associated with obesity

  4. Insulin secretion and insulin resistance in Korean women with gestational diabetes mellitus and impaired glucose tolerance.

    Science.gov (United States)

    Yang, Sae Jeong; Kim, Tae Nyun; Baik, Sei Hyun; Kim, Tae Sun; Lee, Kwan Woo; Nam, Moonsuk; Park, Yong Soo; Woo, Jeong-Teak; Kim, Young Seol; Kim, Sung-Hoon

    2013-05-01

    The aim was to compare the insulin sensitivity and secretion index of pregnant Korean women with normal glucose tolerance (NGT), gestational impaired glucose tolerance (GIGT; only one abnormal value according to the Carpenter and Coustan criteria), and gestational diabetes mellitus (GDM). A cross-sectional study was performed with 1,163 pregnant women with positive (1-hour plasma glucose ≥ 7.2 mmol/L) in a 50-g oral glucose challenge test (OGCT). The 100-g oral glucose tolerance test (OGTT) was used to stratify the participants into three groups: NGT (n = 588), GIGT (n = 294), and GDM (n = 281). The GDM group had higher homeostasis model assessment of insulin resistance and lower insulin sensitivity index (ISOGTT), quantitative insulin sensitivity check index, homeostasis model assessment for estimation of index β-cell secretion (HOMA-B), first and second phase insulin secretion, and insulin secretion-sensitivity index (ISSI) than the NGT group (p ≤ 0.001 for all). Moreover, the GIGT group had lower ISOGTT, HOMA-B, first and second phase insulin secretion, and ISSI than the NGT group (p insulin secretion status than the 3-hour abnormal levels group. Korean women with GDM show impairments of both insulin secretion and insulin sensitivity. In addition, GIGT is associated with both β-cell dysfunction and insulin resistance.

  5. Persistence of insulin resistance in polycystic ovarian disease after inhibition of ovarian steroid secretion.

    Science.gov (United States)

    Geffner, M E; Kaplan, S A; Bersch, N; Golde, D W; Landaw, E M; Chang, R J

    1986-03-01

    Six nonobese women with polycystic ovarian disease (PCOD) showed significant hyperinsulinemia, compared with controls after oral glucose (P less than 0.05). As an indicator of insulin sensitivity, in vitro proliferation of erythrocyte progenitor cells of PCOD subjects exposed to physiologic concentrations of insulin was significantly blunted (P less than 0.001). Monocyte insulin receptor binding was not impaired in the PCOD subjects. Three of the PCOD patients were treated with a long-acting gonadotropin-releasing hormone agonist for 6 months, which resulted in marked suppression of ovarian androgen secretion but no demonstrable changes in in vivo or in vitro indicators of insulin resistance. Thus insulin resistance in PCOD subjects appears to be unrelated to ovarian hyperandrogenism (or acanthosis or obesity). Although certain tissues are insulin-resistant in PCOD patients, the ovary may remain sensitive and overproduce androgens in response to high circulating insulin levels.

  6. Roles of circulating WNT-signaling proteins and WNT-inhibitors in human adiposity, insulin resistance, insulin secretion, and inflammation.

    Science.gov (United States)

    Almario, R U; Karakas, S E

    2015-02-01

    Wingless-type MMTV integration site family member (WNT) signaling and WNT-inhibitors have been implicated in regulation of adipogenesis, insulin resistance, pancreatic function, and inflammation. Our goal was to determine serum proteins involved in WNT signaling (WNT5 and WISP2) and WNT inhibition (SFRP4 and SFRP5) as they relate to obesity, serum adipokines, insulin resistance, insulin secretion, and inflammation in humans. Study population comprised 57 insulin resistant women with polycystic ovary syndrome (PCOS) and 27 reference women. In a cross-sectional study, blood samples were obtained at fasting, during oral, and frequently sampled intravenous glucose tolerance tests. Serum WNT5, WISP2, and SFRP4 concentrations did not differ between PCOS vs. reference women. Serum WNT5 correlated inversely with weight both in PCOS and reference women, and correlated directly with insulin response during oral glucose tolerance test in PCOS women. Serum WISP2 correlated directly with fatty acid binding protein 4. Serum SFRP5 did not differ between obese (n=32) vs. nonobese (n=25) PCOS women, but reference women had lower SFRP5 (pPCOS groups). Serum SFRP5 correlated inversely with IL-1β, TNF-α, cholesterol, and apoprotein B. These findings demonstrated that WNT5 correlated inversely with adiposity and directly with insulin response, and the WNT-inhibitor SFRP5 may be anti-inflammatory. Better understanding of the role of WNT signaling in obesity, insulin resistance, insulin secretion, lipoprotein metabolism, and inflammation is important for prevention and treatment of metabolic syndrome, diabetes and cardiovascular disease. © Georg Thieme Verlag KG Stuttgart · New York.

  7. OPA1 deficiency promotes secretion of FGF21 from muscle that prevents obesity and insulin resistance.

    Science.gov (United States)

    Pereira, Renata Oliveira; Tadinada, Satya M; Zasadny, Frederick M; Oliveira, Karen Jesus; Pires, Karla Maria Pereira; Olvera, Angela; Jeffers, Jennifer; Souvenir, Rhonda; Mcglauflin, Rose; Seei, Alec; Funari, Trevor; Sesaki, Hiromi; Potthoff, Matthew J; Adams, Christopher M; Anderson, Ethan J; Abel, E Dale

    2017-07-14

    Mitochondrial dynamics is a conserved process by which mitochondria undergo repeated cycles of fusion and fission, leading to exchange of mitochondrial genetic content, ions, metabolites, and proteins. Here, we examine the role of the mitochondrial fusion protein optic atrophy 1 (OPA1) in differentiated skeletal muscle by reducing OPA1 gene expression in an inducible manner. OPA1 deficiency in young mice results in non-lethal progressive mitochondrial dysfunction and loss of muscle mass. Mutant mice are resistant to age- and diet-induced weight gain and insulin resistance, by mechanisms that involve activation of ER stress and secretion of fibroblast growth factor 21 (FGF21) from skeletal muscle, resulting in increased metabolic rates and improved whole-body insulin sensitivity. OPA1-elicited mitochondrial dysfunction activates an integrated stress response that locally induces muscle atrophy, but via secretion of FGF21 acts distally to modulate whole-body metabolism. © 2017 The Authors.

  8. Familial hyperinsulinemia associated with secretion of an abnormal insulin, and coexistence of insulin resistance in the propositus.

    Science.gov (United States)

    Vinik, A I; Seino, S; Funakoshi, A; Schwartz, J; Matsumoto, M; Schteingart, D E; Fu, Z Z; Tsai, S T

    1986-04-01

    A 45-yr-old muscular nonobese white man who had a 9-yr history of syncopal episodes was studied on several occasions between April 1979 and August 1984. Fasting glucose concentrations ranged between 74-115 mg/dl, and those of insulin ranged between 14-64 microU/ml. Reactive hypoglycemia 3-4 h after ingestion of glucose occurred in the first 2 yr. Glucose tolerance was impaired in 1979, from February 1982 through September 1983, and again in August 1984. The maximum plasma insulin response to glucose ranged between 475-1630 microU/ml. When studied in November 1982, insulin (0.1 U/kg) caused a fall in blood glucose concentration of only 25% (normal, greater than 50%), and maximal glucose utilization during the euglycemic hyperinsulinemic clamp was 7.5 mg/kg . min (normal, greater than 12 mg/kg . min). Plasma counterregulatory hormone concentrations were normal, and antibodies to insulin and the insulin receptor were absent. Binding of exogenous insulin to the patient's cellular receptors (monocytes, red blood cells, and skin fibroblasts) was normal. Insulin was purified from plasma by immunoaffinity and molecular sieve chromatography and was found to elute later than human insulin on reversed phase high performance liquid chromatography. It was more hydrophobic than normal human insulin and had only 10% of the activity of normal insulin in terms of ability to bind to and stimulate glucose metabolism in isolated rat adipocytes. The abnormal insulin was identified in two of three sons and a sister, but not in the mother, brother, or niece. Sensitivity to insulin was normal in the two sons who had abnormal insulin. These results suggest that in this family the abnormal insulin was due to a biosynthetic defect, inherited as an autosomal dominant trait. The hyperinsulinemia was not associated with diabetes in family members who had no insulin resistance.

  9. Insulin resistance in dairy cows.

    Science.gov (United States)

    De Koster, Jenne D; Opsomer, Geert

    2013-07-01

    Glucose is the molecule that drives milk production, and insulin plays a pivotal role in the glucose metabolism of dairy cows. The effect of insulin on the glucose metabolism is regulated by the secretion of insulin by the pancreas and the insulin sensitivity of the skeletal muscles, the adipose tissue, and the liver. Insulin resistance may develop as part of physiologic (pregnancy and lactation) and pathologic processes, which may manifest as decreased insulin sensitivity or decreased insulin responsiveness. A good knowledge of the normal physiology of insulin is needed to measure the in vivo insulin resistance of dairy cows. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Effects of acute and chronic attenuation of postprandial hyperglycemia on postglucose-load endothelial function in insulin resistant individuals: is stimulation of first phase insulin secretion beneficial for the endothelial function?

    DEFF Research Database (Denmark)

    Major-Pedersen, A; Ihlemann, N; Hermann, T S

    2008-01-01

    The aim of the study is to determine if attenuation of postprandial hyperglycemia, by acutely and chronically enhancing postprandial insulin secretion in insulin-resistant individuals, improves the endothelial dysfunction. We assessed postoral glucose-load endothelial function in 56 insulin....... We found no relationship between postprandial hyperglycemia and post-OGL FMD....

  11. Insulin Resistance

    DEFF Research Database (Denmark)

    Jensen, Benjamin Anderschou Holbech

    Insulin resistance (IR) is escalating with alarming pace and is no longer restricted to westernized countries. As a forerunner for some of the most serious threats to human health including metabolic syndrome, cardiovascular diseases, and type 2-diabetes, the need for new treatment modalities...... interventions. We further show that improving the inflammatory toning, using fish oil as fat source, protects mice against diet induced obesity and -inflammation while preserving insulin sensitivity, even in the absence of free fatty acid receptor 4. Conversely, HFD-induced intestinal dysbiosis is associated...

  12. Adipokines and Hepatic Insulin Resistance

    Science.gov (United States)

    Hassan, Waseem

    2013-01-01

    Obesity is a major risk factor for insulin resistance and type 2 diabetes. Adipose tissue is now considered to be an active endocrine organ that secretes various adipokines such as adiponectin, leptin, resistin, tumour necrosis factor-α, and interleukin-6. Recent studies have shown that these factors might provide a molecular link between increased adiposity and impaired insulin sensitivity. Since hepatic insulin resistance plays the key role in the whole body insulin resistance, clarification of the regulatory processes about hepatic insulin resistance by adipokines in rodents and human would seem essential in order to understand the mechanism of type 2 diabetes and for developing novel therapeutic strategies to treat it. PMID:23762871

  13. Insulin secretion and insulin action in non-insulin-dependent diabetes mellitus: which defect is primary?

    Science.gov (United States)

    Reaven, G M

    1984-01-01

    Defects in both insulin secretion and insulin action exist in patients with non-insulin-dependent diabetes mellitus (NIDDM). The loss of the acute plasma insulin response to intravenous glucose is seen in patients with relatively mild degrees of fasting hyperglycemia, but patients with severe fasting hyperglycemia also demonstrate absolute hypoinsulinemia in response to an oral glucose challenge. In contrast, day-long circulating insulin levels are within normal limits even in severely hyperglycemic patients with NIDDM. The relationship between NIDDM and insulin action in NIDDM is less complex, and is a characteristic feature of the syndrome. This metabolic defect is independent of obesity, and the severity of the resistance to insulin-stimulated glucose uptake increases with magnitude of hyperglycemia. Control of hyperglycemia with exogenous insulin ameliorates the degree of insulin resistance, and reduction of insulin resistance with weight loss in obese patients with NIDDM leads to an enhanced insulin response. Since neither therapeutic intervention is capable of restoring all metabolic abnormalities to normal, these observations do not tell us which of these two defects is primarily responsible for the development of NIDDM. Similarly, the observation that most patients with impaired glucose tolerance are hyperinsulinemic and insulin resistant does not prove that insulin resistance is the primary defect in NIDDM. In conclusion, reduction in both insulin secretion and action is seen in patients with NIDDM, and the relationship between these two metabolic abnormalities is very complex.(ABSTRACT TRUNCATED AT 250 WORDS)

  14. The T-allele of TCF7L2 rs7903146 associates with a reduced compensation of insulin secretion for insulin resistance induced by 9 days of bed rest

    DEFF Research Database (Denmark)

    Alibegovic, Amra C; Sonne, Mette P; Højbjerre, Lise

    2010-01-01

    of FPIR in response to insulin resistance induced by bed rest was lower in carriers of the T-allele (P hepatic insulin resistance......OBJECTIVE: The aim of this study was to determine whether the type 2 diabetes-associated T-allele of transcription factor 7-like 2 (TCF7L2) rs7903146 associates with impaired insulin secretion to compensate for insulin resistance induced by bed rest. RESEARCH DESIGN AND METHODS: A total of 38....... The genetic analyses were done assuming a dominant model of inheritance. RESULTS: The first-phase insulin response (FPIR) was significantly lower in carriers of the T-allele compared with carriers of the CC genotype before bed rest, with and without correction for insulin resistance. The incremental rise...

  15. Vitamin D deficiency impairs glucose-stimulated insulin secretion and increases insulin resistance by reducing PPAR-γ expression in nonobese Type 2 diabetic rats.

    Science.gov (United States)

    Park, Sunmin; Kim, Da Sol; Kang, Suna

    2016-01-01

    Human studies have provided relatively strong associations of poor vitamin D status with Type 2 diabetes but do not explain the nature of the association. Here, we explored the physiological pathways that may explain how vitamin D status modulates energy, lipid and glucose metabolisms in nonobese Type 2 diabetic rats. Goto-Kakizaki (GK) rats were fed high-fat diets containing 25 (VD-low), 1000 (VD-normal) or 10,000 (VD-high) cholecalciferol-IU/kg diet for 8 weeks. Energy expenditure, insulin resistance, insulin secretory capacity and lipid metabolism were measured. Serum 25-OH-D levels, an index of vitamin D status, increased dose dependently with dietary vitamin D. VD-low resulted in less fat oxidation without a significant difference in energy expenditure and less lean body mass in the abdomen and legs comparison to the VD-normal group. In comparison to VD-low, VD-normal had lower serum triglycerides and intracellular fat accumulation in the liver and skeletal muscles which was associated with down-regulation of the mRNA expressions of sterol regulatory element binding protein-1c and fatty acid synthase and up-regulation of gene expressions of peroxisome proliferator-activated receptors (PPAR)-α and carnitine palmitoyltransferase-1. In euglycemic hyperinsulinemic clamp, whole-body and hepatic insulin resistance was exacerbated in the VD-low group but not in the VD-normal group, possibly through decreasing hepatic insulin signaling and PPAR-γ expression in the adipocytes. In 3T3-L1 adipocytes 1,25-(OH)2-D (10 nM) increased triglyceride accumulation by elevating PPAR-γ expression and treatment with a PPAR-γ antagonist blocked the triglyceride deposition induced by 1,25-(OH)2-D treatment. VD-low impaired glucose-stimulated insulin secretion in hyperglycemic clamp and decreased β-cell mass by decreasing β-cell proliferation. In conclusion, vitamin D deficiency resulted in the dysregulation of glucose metabolism in GK rats by simultaneously increasing insulin

  16. Insulin secretion and action in North Indian women during pregnancy.

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    Arora, G P; Almgren, P; Thaman, R G; Pal, A; Groop, L; Vaag, A; Prasad, R B; Brøns, C

    2017-10-01

    The relative roles(s) of impaired insulin secretion vs. insulin resistance in the development of gestational diabetes mellitus depend upon multiple risk factors and diagnostic criteria. Here, we explored their relative contribution to gestational diabetes as defined by the WHO 1999 (GDM1999) and adapted WHO 2013 (GDM2013) criteria, excluding the 1-h glucose value, in a high-risk Indian population from Punjab. Insulin secretion (HOMA2-B) and insulin action (HOMA2-IR) were assessed in 4665 Indian women with or without gestational diabetes defined by the GDM1999 or adapted GDM2013 criteria. Gestational diabetes defined using both criteria was associated with decreased insulin secretion compared with pregnant women with normal glucose tolerance. Women with gestational diabetes defined by the adapted GDM2013, but not GDM1999 criteria, were more insulin resistant than pregnant women with normal glucose tolerance, and furthermore displayed lower insulin secretion than GDM1999 women. Urban habitat, illiteracy, high age and low BMI were independently associated with reduced insulin secretion, whereas Sikh religion, increasing age and BMI, as well as a family history of diabetes were independently associated with increased insulin resistance. Gestational diabetes risk factors influence insulin secretion and action in North Indian women in a differential manner. Gestational diabetes classified using the adapted GDM2013 compared with GDM1999 criteria is associated with more severe impairments of insulin secretion and action. © 2017 Diabetes UK.

  17. Insulin secretion in lipodystrophic HIV-infected patients is associated with high levels of nonglucose secretagogues and insulin resistance of beta-cells

    DEFF Research Database (Denmark)

    Haugaard, Steen B; Andersen, Ove; Storgaard, Heidi

    2004-01-01

    lipodystrophy (controls). Thirty minutes before start of the clamp, a bolus of glucose was injected intravenously to stimulate endogenous insulin secretion. Insulin sensitivity index (SiRd) was estimated from glucose tracer analysis. LIPO displayed increased basal ISR (69%), clamp ISR (114%), basal insulin (130......, and glucose (all r > 0.41, P triglyceride, and glucagon (all r > 0.51, P triglyceride (r = 0.45, P ...%), and clamp insulin (32%), all P 0.65, P glucose. In control subjects, ISR(basal) correlated significantly with insulin, glucagon...

  18. Plasma Asprosin Concentrations Are Increased in Individuals with Glucose Dysregulation and Correlated with Insulin Resistance and First-Phase Insulin Secretion

    Directory of Open Access Journals (Sweden)

    Yuren Wang

    2018-01-01

    Full Text Available Background. Adipokines are reported to participate in many common pathologic processes of glucose dysregulation, such as insulin resistance, β-cell dysfunction, and chronic inflammation. Objective. To detect the concentrations of plasma asprosin in subjects with impaired glucose regulation (IGR and newly diagnosed type 2 diabetes (nT2DM and its relationship to parameters of glucose and lipid metabolism, insulin resistance, and pancreatic β-cell function. Methods. 143 eligible participants were included and were divided into three groups including normal glucose regulation (NGR, n=52, IGR (n=40, and nT2DM group (n=51. The intravenous glucose tolerance test (IVGTT and clinical and biochemical parameters were measured in all participants. Results. Plasma asprosin levels were higher in IGR (82.40 ± 91.06 ng/mL, P<0.001 and nT2DM (73.25 ± 91.69 ng/mL, P<0.001 groups compared with those in the NGR (16.22 ± 9.27 ng/mL group, especially in IGR subjects. Correlation analysis showed that plasma asprosin levels were positively correlated with waist circumference (Wc, fasting plasma glucose (FPG, postchallenge plasma glucose (2hPG, HbA1c, triglyceride (TG, and homeostasis model assessment for insulin resistance (HOMA-IR and negatively correlated with homeostasis model assessment for β-cell function (HOMA-β, area under the curve of the first-phase (0–10 min insulin secretion (AUC, acute insulin response (AIR, and glucose disposition index (GDI (all P<0.05. Multiple logistical regression analyses revealed that plasma asprosin concentrations were significantly correlated with IGR and nT2DM after controlling for age, sex, BMI, and WHR. Conclusions. Circulating asprosin might be a predictor of early diagnosis in DM and might be a potential therapeutic target for prediabetes and T2DM.

  19. Molecular Mechanisms of Insulin Secretion and Insulin Action.

    Science.gov (United States)

    Flatt, Peter R.; Bailey, Clifford J.

    1991-01-01

    Information and current ideas on the factors regulating insulin secretion, the mechanisms underlying the secretion and biological actions of insulin, and the main characteristics of diabetes mellitus are presented. (Author)

  20. Insulin Resistance and Mitochondrial Dysfunction.

    Science.gov (United States)

    Gonzalez-Franquesa, Alba; Patti, Mary-Elizabeth

    2017-01-01

    Insulin resistance precedes and predicts the onset of type 2 diabetes (T2D) in susceptible humans, underscoring its important role in the complex pathogenesis of this disease. Insulin resistance contributes to multiple tissue defects characteristic of T2D, including reduced insulin-stimulated glucose uptake in insulin-sensitive tissues, increased hepatic glucose production, increased lipolysis in adipose tissue, and altered insulin secretion. Studies of individuals with insulin resistance, both with established T2D and high-risk individuals, have consistently demonstrated a diverse array of defects in mitochondrial function (i.e., bioenergetics, biogenesis and dynamics). However, it remains uncertain whether mitochondrial dysfunction is primary (critical initiating defect) or secondary to the subtle derangements in glucose metabolism, insulin resistance, and defective insulin secretion present early in the course of disease development. In this chapter, we will present the evidence linking mitochondrial dysfunction and insulin resistance, and review the potential for mitochondrial targets as a therapeutic approach for T2D.

  1. Insulin secretion and action in North Indian women during pregnancy

    DEFF Research Database (Denmark)

    Arora, G P; Almgren, P; Thaman, R G

    2017-01-01

    . RESULTS: Gestational diabetes defined using both criteria was associated with decreased insulin secretion compared with pregnant women with normal glucose tolerance. Women with gestational diabetes defined by the adapted GDM2013, but not GDM1999 criteria, were more insulin resistant than pregnant women......AIM: The relative roles(s) of impaired insulin secretion vs. insulin resistance in the development of gestational diabetes mellitus depend upon multiple risk factors and diagnostic criteria. Here, we explored their relative contribution to gestational diabetes as defined by the WHO 1999 (GDM1999...... independently associated with increased insulin resistance. CONCLUSIONS: Gestational diabetes risk factors influence insulin secretion and action in North Indian women in a differential manner. Gestational diabetes classified using the adapted GDM2013 compared with GDM1999 criteria is associated with more...

  2. Insulin Resistance and Prediabetes

    Science.gov (United States)

    ... Your Baby is Born Monogenic Diabetes Insulin Resistance & Prediabetes Insulin resistance and prediabetes occur when your body ... will stay in the healthy range. What is prediabetes? Prediabetes means your blood glucose levels are higher ...

  3. Aβ-Induced Insulin Resistance and the Effects of Insulin on the Cholesterol Synthesis Pathway and Aβ Secretion in Neural Cells.

    Science.gov (United States)

    Najem, Dema; Bamji-Mirza, Michelle; Yang, Ze; Zhang, Wandong

    2016-06-01

    Alzheimer's disease (AD) is characterized by amyloid-β (Aβ) toxicity, tau pathology, insulin resistance, neuroinflammation, and dysregulation of cholesterol homeostasis, all of which play roles in neurodegeneration. Insulin has polytrophic effects on neurons and may be at the center of these pathophysiological changes. In this study, we investigated possible relationships among insulin signaling and cholesterol biosynthesis, along with the effects of Aβ42 on these pathways in vitro. We found that neuroblastoma 2a (N2a) cells transfected with the human gene encoding amyloid-β protein precursor (AβPP) (N2a-AβPP) produced Aβ and exhibited insulin resistance by reduced p-Akt and a suppressed cholesterol-synthesis pathway following insulin treatment, and by increased phosphorylation of insulin receptor subunit-1 at serine 612 (p-IRS-S612) as compared to parental N2a cells. Treatment of human neuroblastoma SH-SY5Y cells with Aβ42 also increased p-IRS-S612, suggesting that Aβ42 is responsible for insulin resistance. The insulin resistance was alleviated when N2a-AβPP cells were treated with higher insulin concentrations. Insulin increased Aβ release from N2a-AβPP cells, by which it may promote Aβ clearance. Insulin increased cholesterol-synthesis gene expression in SH-SY5Y and N2a cells, including 24-dehydrocholesterol reductase (DHCR24) and 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGCR) through sterol-regulatory element-binding protein-2 (SREBP2). While Aβ42-treated SH-SY5Y cells exhibited increased HMGCR expression and c-Jun phosphorylation as pro-inflammatory responses, they also showed down-regulation of neuro-protective/anti-inflammatory DHCR24. These results suggest that Aβ42 may cause insulin resistance, activate JNK for c-Jun phosphorylation, and lead to dysregulation of cholesterol homeostasis, and that enhancing insulin signaling may relieve the insulin-resistant phenotype and the dysregulated cholesterol-synthesis pathway to promote A

  4. Maternal Moderate Physical Training during Pregnancy Attenuates the Effects of a Low-Protein Diet on the Impaired Secretion of Insulin in Rats: Potential Role for Compensation of Insulin Resistance and Preventing Gestational Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Carol Góis Leandro

    2012-01-01

    Full Text Available The effects of pregestational and gestational low-to-moderate physical training on insulin secretion in undernourished mothers were evaluated. Virgin female Wistar rats were divided into four groups as follows: control (C, n=5; trained (T, n=5; low-protein diet (LP, n=5; trained with a low-protein diet (T + LP, n=5. Trained rats ran on a treadmill over a period of 4 weeks before mate (5 days week−1 and 60 min day−1, at 65% of VO2max. At pregnancy, the intensity and duration of the exercise were reduced. Low-protein groups were provided with an 8% casein diet, and controls were provided with a 17% casein diet. At third day after delivery, mothers and pups were killed and islets were isolated by collagenase digestion of pancreas and incubated for a further 1 h with medium containing 5.6 or 16.7 mM glucose. T mothers showed increased insulin secretion by isolated islets incubated with 16.7 mM glucose, whereas LP group showed reduced secretion of insulin by isolated islets when compared with both C and LP + T groups. Physical training before and during pregnancy attenuated the effects of a low-protein diet on the secretion of insulin, suggesting a potential role for compensation of insulin resistance and preventing gestational diabetes mellitus.

  5. Sensitive and specific markers for insulin resistance, hyperandrogenemia, and inappropriate gonadotrophin secretion in women with polycystic ovary syndrome: a case-control study from Bahrain

    Directory of Open Access Journals (Sweden)

    Al-Ayadhi MA

    2012-05-01

    Full Text Available Jamal Golbahar,1,2,* Maha Al-Ayadhi,2,* Negalla Mohan Das,2 Khalid Gumaa,2 1Department of Molecular Medicine, Al-Jawhara Centre for Genetic Diagnosis and Research, 2Department of Medical Biochemistry, College of Medicine and Medical Sciences, AGU, Manama, Bahrain *These authors contributed equally to this articleBackground: In women with polycystic ovary syndrome (PCOS, despite a high prevalence of insulin resistance, hyperandrogenemia, and disturbances in the secretion of gonadotrophin, the principal causes of biochemical abnormalities and the best endocrine markers for PCOS have not been fully identified.Subjects and methods: Serum levels of insulin, glucose, follicle-stimulating hormone (FSH, luteinizing hormone (LH, total testosterone, estrogen, sex hormone-binding capacity (SHBG, and other related indices such as homeostasis model assessment, insulin glucose ratios, LH/FSH ratios, and the free androgen index (FAI were determined and compared in women with PCOS (n = 50 and women without PCOS (n = 50.Results: In multivariate logistic regression analyses, among all insulin resistance indices, only hyperinsulinemia (odds ratio [OR] = 2.6; confidence interval [CI]: 1.3–5.2; P = 0.008 was significantly and independently associated with PCOS when adjusted for body mass index (BMI, hyperandrogenemia, and LH/FSH ratios. The LH/FSH ratio (OR = 5.4; CI: 1.2–23.0, P = 0.03 was the only marker among those indices for inappropriate gonadotrophin secretion that significantly and independently associated with PCOS when adjusted for BMI and hyperinsulinemia. Among those indices for hyperandrogenemia, FAI (OR = 1.1; CI: 1.0–2.7; P = 0.02 and SHBG (OR = 1.2; CI: 1.2–3.4; P = 0.03 were significantly and independently associated with PCOS when adjusted for BMI and hyperinsulinemia. In addition, receiver operating characteristic analysis showed that the best predictive markers for PCOS were insulin (area under the curve [AUC] = 0.944; CI: 0.887–0

  6. Glycosphingolipids and insulin resistance

    NARCIS (Netherlands)

    Langeveld, Mirjam; Aerts, Johannes M. F. G.

    2009-01-01

    Obesity is associated with an increased risk for insulin resistance, a state characterized by impaired responsiveness of liver, muscle and adipose tissue to insulin. One class of lipids involved in the development of insulin resistance are the (glyco)sphingolipids. Ceramide, the most simple

  7. Evaluation of insulin secretion and action in New World camelids.

    Science.gov (United States)

    Firshman, Anna M; Cebra, Christopher K; Schanbacher, Barbara J; Seaquist, Elizabeth R

    2013-01-01

    To measure and compare insulin secretion and sensitivity in healthy alpacas and llamas via glucose clamping techniques. 8 llamas and 8 alpacas. Hyperinsulinemic euglycemic clamping (HEC) and hyperglycemic clamping (HGC) were performed on each camelid in a crossover design with a minimum 48-hour washout period between clamping procedures. The HEC technique was performed to measure insulin sensitivity. Insulin was infused IV at 6 mU/min/kg for 4 hours, and an IV infusion of glucose was adjusted to maintain blood glucose concentration at 150 mg/dL. Concentrations of blood glucose and plasma insulin were determined throughout. The HGC technique was performed to assess insulin secretion in response to exogenous glucose infusion. An IV infusion of glucose was administered to maintain blood glucose concentration at 320 mg/dL for 3 hours, and concentrations of blood glucose and plasma insulin were determined throughout. Alpacas and llamas were not significantly different with respect to whole-body insulin sensitivity during HEC or in pancreatic β-cell response during HGC. Alpacas and llamas had markedly lower insulin sensitivity during HEC and markedly lower pancreatic β-cell response during HGC, in comparison with many other species. New World camelids had lower glucose-induced insulin secretion and marked insulin resistance in comparison with other species. This likely contributes to the disorders of fat and glucose metabolism that are common to camelids.

  8. Insulin Resistance of Puberty.

    Science.gov (United States)

    Kelsey, Megan M; Zeitler, Philip S

    2016-07-01

    Puberty is a time of considerable metabolic and hormonal change. Notably, puberty is associated with a marked decrease in insulin sensitivity, on par with that seen during pregnancy. In otherwise healthy youth, there is a nadir in insulin sensitivity in mid-puberty, and then it recovers at puberty completion. However, there is evidence that insulin resistance (IR) does not resolve in youth who are obese going into puberty and may result in increased cardiometabolic risk. Little is known about the underlying pathophysiology of IR in puberty, and how it might contribute to increased disease risk (e.g., type 2 diabetes). In this review, we have outlined what is known about the IR in puberty in terms of pattern, potential underlying mechanisms and other mediating factors. We also outline other potentially related metabolic changes that occur during puberty, and effects of underlying insulin resistant states (e.g., obesity) on pubertal changes in insulin sensitivity.

  9. Insulin resistance alters islet morphology in nondiabetic humans

    DEFF Research Database (Denmark)

    Mezza, Teresa; Muscogiuri, Giovanna; Sorice, Gian Pio

    2014-01-01

    Type 2 diabetes is characterized by poor glucose uptake in metabolic tissues and manifests when insulin secretion fails to cope with worsening insulin resistance. In addition to its effects on skeletal muscle, liver, and adipose tissue metabolism, it is evident that insulin resistance also affects...... pancreatic β-cells. To directly examine the alterations that occur in islet morphology as part of an adaptive mechanism to insulin resistance, we evaluated pancreas samples obtained during pancreatoduodenectomy from nondiabetic subjects who were insulin-resistant or insulin-sensitive. We also compared...... insulin sensitivity, insulin secretion, and incretin levels between the two groups. We report an increased islet size and an elevated number of β- and α-cells that resulted in an altered β-cell-to-α-cell area in the insulin- resistant group. Our data in this series of studies suggest that neogenesis from...

  10. Factors influencing insulin secretion from encapsulated islets

    NARCIS (Netherlands)

    de Haan, BJ; Faas, MM; de Vos, P

    2003-01-01

    Adequate regulation of glucose levels by a microencapsulated pancreatic islet graft requires a minute-to-minute regulation of blood glucose. To design such a transplant, it is mandatory to have sufficient insight in factors influencing the kinetics of insulin secretion by encapsulated islets. The

  11. Impact of objectively measured sedentary behaviour on changes in insulin resistance and secretion over 3 years in the RISC study

    DEFF Research Database (Denmark)

    Lahjibi, E; Heude, B; Dekker, J M

    2013-01-01

    The importance of reducing sedentary time is increasingly being recognized in the prevention of diabetes and cardiovascular disease. Despite this, the prospective association between sedentary time and physical activity with insulin sensitivity and cardiometabolic risk factors has been little stu...

  12. In nondiabetic, human immunodeficiency virus-infected patients with lipodystrophy, hepatic insulin extraction and posthepatic insulin clearance rate are decreased in proportion to insulin resistance

    DEFF Research Database (Denmark)

    Haugaard, Steen B; Andersen, Ove; Hansen, Birgitte R

    2005-01-01

    In healthy, nondiabetic individuals with insulin resistance, fasting insulin is inversely correlated to the posthepatic insulin clearance rate (MCRi) and the hepatic insulin extraction (HEXi). We investigated whether similar early mechanisms to facilitate glucose homeostasis exist in nondiabetic...... endogenous insulin secretion, which was estimated by deconvolution of C-peptide concentrations. Hepatic extraction of insulin was calculated as 1 minus the ratio of fasting posthepatic insulin delivery rate to fasting endogenous insulin secretion rate. Compared with controls, LIPO displayed increased fasting...... insulin (130%, P Hepatic extraction of insulin was similar between groups (LIPO, 55%; controls, 57%; P > .8). In LIPO, HEXi and MCRi correlated inversely with fasting insulin (r = -0.56, P

  13. Insulin secretion and sensitivity in space flight: diabetogenic effects

    Science.gov (United States)

    Tobin, Brian W.; Uchakin, Peter N.; Leeper-Woodford, Sandra K.

    2002-01-01

    Nearly three decades of space flight research have suggested that there are subclinical diabetogenic changes that occur in microgravity. Alterations in insulin secretion, insulin sensitivity, glucose tolerance, and metabolism of protein and amino acids support the hypothesis that insulin plays an essential role in the maintenance of muscle mass in extended-duration space flight. Experiments in flight and after flight and ground-based bedrest studies have associated microgravity and its experimental paradigms with manifestations similar to those of diabetes, physical inactivity, and aging. We propose that these manifestations are characterized best by an etiology that falls into the clinical category of "other" causes of diabetes, including, but not restricted to, genetic beta-cell defects, insulin action defects, diseases of the endocrine pancreas, endocrinopathies, drug or chemically induced diabetes, infections, immune-mediated metabolic alteration, and a host of genetic related diseases. We present data showing alterations in tumor necrosis factor-alpha production, insulin secretion, and amino acid metabolism in pancreatic islets of Langerhans cultured in a ground-based cell culture bioreactor that mimics some of the effects of microgravity. Taken together, space flight research, ground-based studies, and bioreactor studies of pancreatic islets of Langerhans support the hypothesis that the pancreas is unable to overcome peripheral insulin resistance and amino acid dysregulation during space flight. We propose that measures of insulin secretion and insulin action will be necessary to design effective countermeasures against muscle loss, and we advance the "disposition index" as an essential model to be used in the clinical management of space flight-induced muscle loss.

  14. SIRT4 Is a Lysine Deacylase that Controls Leucine Metabolism and Insulin Secretion

    DEFF Research Database (Denmark)

    Anderson, Kristin A; Huynh, Frank K; Fisher-Wellman, Kelsey

    2017-01-01

    in leucine oxidation, and we show a primary role for SIRT4 in controlling this pathway in mice. Furthermore, we find that dysregulated leucine metabolism in SIRT4KO mice leads to elevated basal and stimulated insulin secretion, which progressively develops into glucose intolerance and insulin resistance....... These findings identify a robust enzymatic activity for SIRT4, uncover a mechanism controlling branched-chain amino acid flux, and position SIRT4 as a crucial player maintaining insulin secretion and glucose homeostasis during aging....

  15. Hormone-sensitive lipase null mice exhibit signs of impaired insulin sensitivity whereas insulin secretion is intact

    DEFF Research Database (Denmark)

    Mulder, Hindrik; Sörhede-Winzell, Maria; Contreras, Juan Antonio

    2003-01-01

    of increased amounts of insulin. Impaired insulin sensitivity was further indicated by retarded glucose disposal during an insulin tolerance test. A euglycemic hyperinsulinemic clamp revealed that hepatic glucose production was insufficiently blocked by insulin in HSL null mice. In vitro, insulin......-stimulated glucose uptake into soleus muscle, and lipogenesis in adipocytes were moderately reduced, suggesting additional sites of insulin resistance. Morphometric analysis of pancreatic islets revealed a doubling of beta-cell mass in HSL null mice, which is consistent with an adaptation to insulin resistance....... Insulin secretion in vitro, examined by perifusion of isolated islets, was not impacted by HSL deficiency. Thus, HSL deficiency results in a moderate impairment of insulin sensitivity in multiple target tissues of the hormone but is compensated by hyperinsulinemia....

  16. The relationship between bone turnover and insulin sensitivity and secretion

    DEFF Research Database (Denmark)

    Frost, Morten; Balkau, Beverley; Hatunic, Mensud

    2018-01-01

    Bone metabolism appears to influence insulin secretion and sensitivity, and insulin promotes bone formation in animals, but similar evidence in humans is limited. The objectives of this study are to explore if bone turnover markers were associated with insulin secretion and sensitivity and to det...

  17. Insulin Resistance in Alzheimer's Disease

    Science.gov (United States)

    Dineley, Kelly T; Jahrling, Jordan B; Denner, Larry

    2014-01-01

    Insulin is a key hormone regulating metabolism. Insulin binding to cell surface insulin receptors engages many signaling intermediates operating in parallel and in series to control glucose, energy, and lipids while also regulating mitogenesis and development. Perturbations in the function of any of these intermediates, which occur in a variety of diseases, cause reduced sensitivity to insulin and insulin resistance with consequent metabolic dysfunction. Chronic inflammation ensues which exacerbates compromised metabolic homeostasis. Since insulin has a key role in learning and memory as well as directly regulating ERK, a kinase required for the type of learning and memory compromised in early Alzheimer's disease (AD), insulin resistance has been identified as a major risk factor for the onset of AD. Animal models of AD or insulin resistance or both demonstrate that AD pathology and impaired insulin signaling form a reciprocal relationship. Of note are human and animal model studies geared toward improving insulin resistance that have led to the identification of the nuclear receptor and transcription factor, peroxisome proliferator-activated receptor gamma (PPARγ) as an intervention tool for early AD. Strategic targeting of alternate nodes within the insulin signaling network has revealed disease-stage therapeutic windows in animal models that coalesce with previous and ongoing clinical trial approaches. Thus, exploiting the connection between insulin resistance and AD provides powerful opportunities to delineate therapeutic interventions that slow or block the pathogenesis of AD. PMID:25237037

  18. Insulin secretion and cellular glucose metabolism after prolonged low-grade intralipid infusion in young men

    DEFF Research Database (Denmark)

    Jensen, Christine B; Storgaard, Heidi; Holst, Jens J

    2003-01-01

    We examined the simultaneous effects of a 24-h low-grade Intralipid infusion on peripheral glucose disposal, intracellular glucose partitioning and insulin secretion rates in twenty young men, by 2-step hyperinsulinemic euglycemic clamp [low insulin clamp (LI), 10 mU/m(2) x min; high insulin clamp...... Intralipid infusion. At LI, glucose oxidation decreased by 10%, whereas glucose disposal, glycolytic flux, glucose storage, and glucose production were not significantly altered. At HI, glucose disposal, and glucose oxidation decreased by 12% and 24%, respectively, during Intralipid infusion. Glycolytic flux......, glucose storage, and glucose production were unchanged. Insulin secretion rates increased in response to Intralipid infusion, but disposition indices (DI = insulin action.insulin secretion) were unchanged. In conclusion, a 24-h low-grade Intralipid infusion caused insulin resistance in the oxidative (but...

  19. Insulin resistance and chronic inflammation

    Directory of Open Access Journals (Sweden)

    Natalia Matulewicz

    2016-12-01

    Full Text Available Insulin resistance is a condition of reduced biological response to insulin. Growing evidence indicates the role of the chronic low-grade inflammatory response in the pathogenesis of insulin resistance. Adipose tissue in obesity is characterized by increased lipolysis with the excessive release of free fatty acids, and is also a source of proinflammatory cytokines. Both these factors may inhibit insulin action. Proinflammatory cytokines exert their effect by stimulating major inflammatory NFκB and JNK pathways within the cells. Inflammatory processes in other insulin responsive tissues may also play a role in inducing insulin resistance. This paper is an overview of the chronic low-grade inflammation in adipose tissue, skeletal muscle, liver and endothelial cells during the development of insulin resistance.

  20. Molecular mechanism of insulin resistance

    Indian Academy of Sciences (India)

    Free fatty acids are known to play a key role in promoting loss of insulin sensitivity, thereby causing insulin resistance and type 2 diabetes. However, the underlying mechanism involved is still unclear. In searching for the cause of the mechanism, it has been found that palmitate inhibits insulin receptor (IR) gene expression, ...

  1. Bimodal effect on pancreatic β-cells of secretory products from normal or insulin-resistant human skeletal muscle

    DEFF Research Database (Denmark)

    Bouzakri, Karim; Plomgaard, Peter; Berney, Thierry

    2011-01-01

    Type 2 diabetes is characterized by insulin resistance with a relative deficiency in insulin secretion. This study explored the potential communication between insulin-resistant human skeletal muscle and primary (human and rat) β-cells.......Type 2 diabetes is characterized by insulin resistance with a relative deficiency in insulin secretion. This study explored the potential communication between insulin-resistant human skeletal muscle and primary (human and rat) β-cells....

  2. Selective Insulin Resistance in Adipocytes*

    Science.gov (United States)

    Tan, Shi-Xiong; Fisher-Wellman, Kelsey H.; Fazakerley, Daniel J.; Ng, Yvonne; Pant, Himani; Li, Jia; Meoli, Christopher C.; Coster, Adelle C. F.; Stöckli, Jacqueline; James, David E.

    2015-01-01

    Aside from glucose metabolism, insulin regulates a variety of pathways in peripheral tissues. Under insulin-resistant conditions, it is well known that insulin-stimulated glucose uptake is impaired, and many studies attribute this to a defect in Akt signaling. Here we make use of several insulin resistance models, including insulin-resistant 3T3-L1 adipocytes and fat explants prepared from high fat-fed C57BL/6J and ob/ob mice, to comprehensively distinguish defective from unaffected aspects of insulin signaling and its downstream consequences in adipocytes. Defective regulation of glucose uptake was observed in all models of insulin resistance, whereas other major actions of insulin such as protein synthesis and anti-lipolysis were normal. This defect corresponded to a reduction in the maximum response to insulin. The pattern of change observed for phosphorylation in the Akt pathway was inconsistent with a simple defect at the level of Akt. The only Akt substrate that showed consistently reduced phosphorylation was the RabGAP AS160 that regulates GLUT4 translocation. We conclude that insulin resistance in adipose tissue is highly selective for glucose metabolism and likely involves a defect in one of the components regulating GLUT4 translocation to the cell surface in response to insulin. PMID:25720492

  3. Immunohistochemical expression of insulin, glucagon, and somatostatin in pancreatic islets of horses with and without insulin resistance.

    Science.gov (United States)

    Newkirk, Kim M; Ehrensing, Gordon; Odoi, Agricola; Boston, Raymond C; Frank, Nicholas

    2018-02-01

    OBJECTIVE To assess insulin, glucagon, and somatostatin expression within pancreatic islets of horses with and without insulin resistance. ANIMALS 10 insulin-resistant horses and 13 insulin-sensitive horses. PROCEDURES For each horse, food was withheld for at least 10 hours before a blood sample was collected for determination of serum insulin concentration. Horses with a serum insulin concentration horses with a serum insulin concentration > 20 μU/mL underwent a frequently sampled IV glucose tolerance test to determine sensitivity to insulin by minimal model analysis. Horses with a sensitivity to insulin horses were euthanized with a barbiturate overdose, and pancreatic specimens were harvested and immunohistochemically stained for determination of insulin, glucagon, and somatostatin expression in pancreatic islets. Islet hormone expression was compared between insulin-resistant and insulin-sensitive horses. RESULTS Cells expressing insulin, glucagon, and somatostatin made up approximately 62%, 12%, and 7%, respectively, of pancreatic islet cells in insulin-resistant horses and 64%, 18%, and 9%, respectively, of pancreatic islet cells in insulin-sensitive horses. Expression of insulin and somatostatin did not differ between insulin-resistant and insulin-sensitive horses, but the median percentage of glucagon-expressing cells in the islets of insulin-resistant horses was significantly less than that in insulin-sensitive horses. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that, in insulin-resistant horses, insulin secretion was not increased but glucagon production might be downregulated as a compensatory response to hyperinsulinemia.

  4. Insulin resistance: definition and consequences.

    Science.gov (United States)

    Lebovitz, H E

    2001-01-01

    Insulin resistance is defined clinically as the inability of a known quantity of exogenous or endogenous insulin to increase glucose uptake and utilization in an individual as much as it does in a normal population. Insulin action is the consequence of insulin binding to its plasma membrane receptor and is transmitted through the cell by a series of protein-protein interactions. Two major cascades of protein-protein interactions mediate intracellular insulin action: one pathway is involved in regulating intermediary metabolism and the other plays a role in controlling growth processes and mitoses. The regulation of these two distinct pathways can be dissociated. Indeed, some data suggest that the pathway regulating intermediary metabolism is diminished in type 2 diabetes while that regulating growth processes and mitoses is normal.--Several mechanisms have been proposed as possible causes underlying the development of insulin resistance and the insulin resistance syndrome. These include: (1) genetic abnormalities of one or more proteins of the insulin action cascade (2) fetal malnutrition (3) increases in visceral adiposity. Insulin resistance occurs as part of a cluster of cardiovascular-metabolic abnormalities commonly referred to as "The Insulin Resistance Syndrome" or "The Metabolic Syndrome". This cluster of abnormalities may lead to the development of type 2 diabetes, accelerated atherosclerosis, hypertension or polycystic ovarian syndrome depending on the genetic background of the individual developing the insulin resistance.--In this context, we need to consider whether insulin resistance should be defined as a disease entity which needs to be diagnosed and treated with specific drugs to improve insulin action.

  5. Decreased hepatic RBP4 secretion is correlated with reduced hepatic glucose production but is not associated with insulin resistance in patients with liver cirrhosis

    NARCIS (Netherlands)

    Bahr, Matthias J.; Boeker, Klaus H. W.; Manns, Michael P.; Tietge, Uwe J. F.

    Patients with liver cirrhosis have a high incidence of insulin resistance and diabetes. This study was designed to determine circulating levels and hepatic production of retinol-binding protein 4 (RBP4) in relation to parameters of hepatic and systemic metabolism in patients with liver cirrhosis.

  6. The evolutionary benefit of insulin resistance

    NARCIS (Netherlands)

    Soeters, Maarten R.; Soeters, Peter B.

    2012-01-01

    Insulin resistance is perceived as deleterious, associated with conditions as the metabolic syndrome, type 2 diabetes mellitus and critical illness. However, insulin resistance is evolutionarily well preserved and its persistence suggests that it benefits survival. Insulin resistance is important in

  7. Radioimmunologic study of insulin secretion during acute radiation sickness

    International Nuclear Information System (INIS)

    Barkalaya, A.I.

    1977-01-01

    Insulin secretion in irradiated (750 R) albino rats has been studied radioimmunologically. The data obtained were correlated with the corticosterone and glucose contents of blood. It has been shown that there is a risk of relative incompetence of insulin secretion during the hypercorticoidism and hyperglycemia

  8. Radioimmunologic study of insulin secretion during acute radiation sickness

    Energy Technology Data Exchange (ETDEWEB)

    Barkalaya, A I

    1977-01-01

    Insulin secretion in irradiated (750 R) albino rats has been studied radioimmunologically. The data obtained were correlated with the corticosterone and glucose contents of blood. It has been shown that there is a risk of relative incompetence of insulin secretion during the hypercorticoidism and hyperglycemia.

  9. Insulin secretion and incretin hormones after oral glucose in non-obese subjects with impaired glucose tolerance

    DEFF Research Database (Denmark)

    Rask, E; Olsson, T; Söderberg, S

    2004-01-01

    of glucose, insulin, C-peptide, GLP-1, and GIP. Insulin secretion (TIS) and insulin sensitivity (OGIS) were assessed using models describing the relationship between glucose, insulin and C-peptide data. These models allowed estimation also of the hepatic extraction of insulin. The age (54.2 +/- 9.7 [mean......Subjects with impaired glucose tolerance (IGT) are usually overweight and exhibit insulin resistance with a defective compensation of insulin secretion. In this study, we sought to establish the interrelation between insulin secretion and insulin sensitivity after oral glucose in non-obese subjects...... over the whole 180-minute period was higher in IGT (26.2 +/- 2.4 v 20.0 +/- 2.0 nmol/L; P =.035). Hepatic insulin extraction correlated linearly with OGIS (r = 0.71; P

  10. Paediatrics, insulin resistance and the kidney.

    Science.gov (United States)

    Marlais, Matko; Coward, Richard J

    2015-08-01

    Systemic insulin resistance is becoming more prevalent in the young due to modern lifestyles predisposing to the metabolic syndrome and obesity. There is also evidence that there are critical insulin-resistant phases for the developing child, including puberty, and that renal disease per se causes systemic insulin resistance. This review considers the factors that render children insulin resistant, as well as the accumulating evidence that the kidney is an insulin-responsive organ and could be affected by insulin resistance.

  11. Moderate alcohol consumption is associated with improved insulin sensitivity, reduced basal insulin secretion rate and lower fasting glucagon concentration in healthy women

    DEFF Research Database (Denmark)

    Bonnet, F; Disse, E; Laville, M

    2012-01-01

    Moderate alcohol consumption is associated with a reduced risk of type 2 diabetes with a stronger effect in women. As the underlying mechanisms remain poorly characterised, we investigated its relationship with insulin resistance, insulin secretion, clearance of insulin and glucagon concentration....

  12. Insulin secretion and cellular glucose metabolism after prolonged low-grade intralipid infusion in young men

    DEFF Research Database (Denmark)

    Jensen, Christine B; Storgaard, Heidi; Holst, Jens Juul

    2003-01-01

    not in the nonoxidative) glucose metabolism in young healthy men. Moreover, insulin hypersecretion perfectly countered the free-fatty acid-induced insulin resistance. Future studies are needed to determine the role of a prolonged moderate lipid load in subjects at increased risk of developing diabetes.......We examined the simultaneous effects of a 24-h low-grade Intralipid infusion on peripheral glucose disposal, intracellular glucose partitioning and insulin secretion rates in twenty young men, by 2-step hyperinsulinemic euglycemic clamp [low insulin clamp (LI), 10 mU/m(2) x min; high insulin clamp...

  13. TLR4 and Insulin Resistance

    Directory of Open Access Journals (Sweden)

    Jane J. Kim

    2010-01-01

    Full Text Available Chronic inflammation is a key feature of insulin resistance and obesity. Toll-Like Receptor 4 (TLR4, involved in modulating innate immunity, is an important mediator of insulin resistance and its comorbidities. TLR4 contributes to the development of insulin resistance and inflammation through its activation by elevated exogenous ligands (e.g., dietary fatty acids and enteric lipopolysaccharide and endogenous ligands (e.g., free fatty acids which are elevated in obese states. TLR4, expressed in insulin target tissues, activates proinflammatory kinases JNK, IKK, and p38 that impair insulin signal transduction directly through inhibitory phosphorylation of insulin receptor substrate (IRS on serine residues. TLR4 activation also leads to increased transcription of pro-inflammatory genes, resulting in elevation of cytokine, chemokine, reactive oxygen species, and eicosanoid levels that promote further insulin-desensitization within the target cell itself and in other cells via paracrine and systemic effects. Increased understanding of cell type-specific TLR4-mediated effects on insulin action present the opportunity and challenge of developing related therapeutic approaches for improving insulin sensitivity while preserving innate immunity.

  14. Adipokines mediate inflammation and insulin resistance

    Directory of Open Access Journals (Sweden)

    Jeffrey E. Pessin

    2013-06-01

    Full Text Available For many years, adipose tissue was considered as an inert energy storage organ that accumulates and stores triacylglycerols during energy excess and releases fatty acids in times of systemic energy need. However, over the last two decades adipose tissue depots have been established as highly active endocrine and metabolically important organs that modulate energy expenditure and glucose homeostasis. In rodents, brown adipose tissue plays an essential role in non-shivering thermogenesis and in energy dissipation that can serve to protect against diet-induced obesity. White adipose tissue collectively referred too as either subcutaneous or visceral adipose tissue is responsible for the secretion of an array of signaling molecules, termed adipokines. These adipokines function as classic circulating hormones to communicate with other organs including brain, liver, muscle, the immune system and adipose tissue itself. The dysregulation of adipokines has been implicated in obesity, type 2 diabetes and cardiovascular disease. Recently, inflammatory responses in adipose tissue have been shown as a major mechanism to induce peripheral tissue insulin resistance. Although leptin and adiponectin regulate feeding behavior and energy expenditure, these adipokines are also involved in the regulation of inflammatory responses. Adipose tissue secrete various pro- and anti-inflammatory adipokines to modulate inflammation and insulin resistance. In obese humans and rodent models, the expression of pro-inflammatory adipokines is enhanced to induce insulin resistance. Collectively, these findings have suggested that obesity-induced insulin resistance may result, at least in part, from an imbalance in the expression of pro- and anti-inflammatory adipokines. Thus we will review the recent progress regarding the physiological and molecular functions of adipokines in the obesity-induced inflammation and insulin resistance with perspectives on future directions.

  15. Insulin Regulates Hepatic Triglyceride Secretion and Lipid Content via Signaling in the Brain.

    Science.gov (United States)

    Scherer, Thomas; Lindtner, Claudia; O'Hare, James; Hackl, Martina; Zielinski, Elizabeth; Freudenthaler, Angelika; Baumgartner-Parzer, Sabina; Tödter, Klaus; Heeren, Joerg; Krššák, Martin; Scheja, Ludger; Fürnsinn, Clemens; Buettner, Christoph

    2016-06-01

    Hepatic steatosis is common in obesity and insulin resistance and results from a net retention of lipids in the liver. A key mechanism to prevent steatosis is to increase secretion of triglycerides (TG) packaged as VLDLs. Insulin controls nutrient partitioning via signaling through its cognate receptor in peripheral target organs such as liver, muscle, and adipose tissue and via signaling in the central nervous system (CNS) to orchestrate organ cross talk. While hepatic insulin signaling is known to suppress VLDL production from the liver, it is unknown whether brain insulin signaling independently regulates hepatic VLDL secretion. Here, we show that in conscious, unrestrained male Sprague Dawley rats the infusion of insulin into the third ventricle acutely increased hepatic TG secretion. Chronic infusion of insulin into the CNS via osmotic minipumps reduced the hepatic lipid content as assessed by noninvasive (1)H-MRS and lipid profiling independent of changes in hepatic de novo lipogenesis and food intake. In mice that lack the insulin receptor in the brain, hepatic TG secretion was reduced compared with wild-type littermate controls. These studies identify brain insulin as an important permissive factor in hepatic VLDL secretion that protects against hepatic steatosis. © 2016 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  16. Increase in homeostasis model assessment of insulin resistance (HOMA-IR) had a strong impact on the development of type 2 diabetes in Japanese individuals with impaired insulin secretion: the Saku study.

    Science.gov (United States)

    Morimoto, Akiko; Tatsumi, Yukako; Soyano, Fumie; Miyamatsu, Naomi; Sonoda, Nao; Godai, Kayo; Ohno, Yuko; Noda, Mitsuhiko; Deura, Kijyo

    2014-01-01

    Our aim was to assess the impact of increase in homeostasis model assessment of insulin resistance (HOMA-IR) on the development of type 2 diabetes in Japanese individuals with impaired insulin secretion (IIS). This study included 2,209 participants aged 30-69 without diabetes at baseline who underwent comprehensive medical check-ups between April 2006 and March 2007 at Saku Central Hospital. Participants were classified into eight groups according to the combination of baseline IIS status (non-IIS and IIS) and category of HOMA-IR change between the baseline and follow-up examinations (decrease, no change/small increase, moderate increase, and large increase). Type 2 diabetes was determined from fasting and 2 h post-load plasma glucose concentrations at the follow-up examination between April 2009 and March 2011. At baseline, 669 individuals (30.3%) were classified as having IIS. At follow-up, 74 individuals developed type 2 diabetes. After adjusting for confounding factors including baseline HOMA-IR values, the multivariable-adjusted odds ratios (95% confidence intervals) for type 2 diabetes in the non-IIS with a decrease (mean change in HOMA-IR: -0.47), non-IIS with a moderate increase (mean change in HOMA-IR: 0.28), non-IIS with a large increase (mean change in HOMA-IR: 0.83), IIS with a decrease (mean change in HOMA-IR: -0.36), IIS with no change/small increase (mean change in HOMA-IR: 0.08), IIS with a moderate increase (mean change in HOMA-IR: 0.27), and IIS with a large increase (mean change in HOMA-IR: 0.73) groups, relative to the non-IIS with no change/small increase (mean change in HOMA-IR: 0.08) group were 0.23 (0.04, 1.11), 1.22 (0.26, 5.72), 2.01 (0.70, 6.46), 1.37 (0.32, 4.28), 3.60 (0.83, 15.57), 5.24 (1.34, 20.52), and 7.01 (1.75, 24.18), respectively. Moderate and large increases in HOMA-IR had a strong impact on the development of type 2 diabetes among individuals with IIS in this Japanese population.

  17. Retinol binding protein 4, obesity, and insulin resistance in adolescents

    Directory of Open Access Journals (Sweden)

    Ronaldi Noor

    2017-02-01

    Full Text Available Background Obesity is a global problem. Even in poor and developing countries, obesity has reached alarming levels. In childhood, obesity may lead to insulin resistance. Retinol binding protein (RBP4, secreted primarily by liver and adipose tissues, was recently proposed as a link between obesity and insulin resistance. The role of RBP4 in pediatric obesity and its relationship with insulin resistance have not been well elucidated. Objective To compare RBP4 levels in obese and lean adolescents and to assess for a relationship between RBP4 levels and insulin resistance. Method This cross-sectional study was conducted in three senior high schools in Padang, West Sumatera, Indonesia. Subjects were adolescents aged 14-18 years, who were obese or normal weight (n=56. We measured subjects’ body mass index (BMI and serum RBP4 concentrations. Insulin resistance was assessed using the homeostasis model assessment of insulin resistance (HOMA-IR index. Results Similar RBP4 levels were found in the obese and normoweight groups (P>0.05. Higher RBP4 levels were found in the insulin resistant compared to the non-insulin resistant group, but the difference was not significant (P > 0.05. Conclusion There is no significant difference in mean RBP4 levels in obese adolescents compared to normoweight adolescents. Nor are mean RBP4 levels significantly different between obese adolescents with and without insulin resistance.

  18. Endocrine determinants of changes in insulin sensitivity and insulin secretion during a weight cycle in healthy men.

    Directory of Open Access Journals (Sweden)

    Judith Karschin

    Full Text Available Changes in insulin sensitivity (IS and insulin secretion occur with perturbations in energy balance and glycemic load (GL of the diet that may precede the development of insulin resistance and hyperinsulinemia. Determinants of changes in IS and insulin secretion with weight cycling in non-obese healthy subjects remain unclear.In a 6wk controlled 2-stage randomized dietary intervention 32 healthy men (26±4y, BMI: 24±2kg/m2 followed 1wk of overfeeding (OF, 3wks of caloric restriction (CR containing either 50% or 65% carbohydrate (CHO and 2wks of refeeding (RF with the same amount of CHO but either low or high glycaemic index at ±50% energy requirement. Measures of IS (basal: HOMA-index, postprandial: Matsuda-ISI, insulin secretion (early: Stumvoll-index, total: tAUC-insulin/tAUC-glucose and potential endocrine determinants (ghrelin, leptin, adiponectin, thyroid hormone levels, 24h-urinary catecholamine excretion were assessed.IS improved and insulin secretion decreased due to CR and normalized upon RF. Weight loss-induced improvements in basal and postprandial IS were associated with decreases in leptin and increases in ghrelin levels, respectively (r = 0.36 and r = 0.62, p<0.05. Weight regain-induced decrease in postprandial IS correlated with increases in adiponectin, fT3, TSH, GL of the diet and a decrease in ghrelin levels (r-values between -0.40 and 0.83, p<0.05 whereas increases in early and total insulin secretion were associated with a decrease in leptin/adiponectin-ratio (r = -0.52 and r = -0.46, p<0.05 and a decrease in fT4 (r = -0.38, p<0.05 for total insulin secretion only. After controlling for GL associations between RF-induced decrease in postprandial IS and increases in fT3 and TSH levels were no longer significant.Weight cycling induced changes in IS and insulin secretion were associated with changes in all measured hormones, except for catecholamine excretion. While leptin, adiponectin and ghrelin seem to be the major

  19. Insulin sensitivity and secretion in Arab Americans with glucose intolerance.

    Science.gov (United States)

    Salinitri, Francine D; Pinelli, Nicole R; Martin, Emily T; Jaber, Linda A

    2013-12-01

    This study examined the pathophysiological abnormalities in Arab Americans with impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT). Homeostasis model assessment of insulin resistance (HOMA-IR), homeostasis model assessment of insulin secretion (HOMA-%β), and the Matsuda Insulin Sensitivity Index composite (ISIcomposite) were calculated from the fasting and stimulated glucose and insulin concentrations measured during the oral glucose tolerance test in a population-based, representative, cross-sectional sample of randomly selected Arab Americans. In total, 497 individuals (42±14 years old; 40% males; body mass index [BMI], 29±6 kg/m(2)) were studied. Multivariate linear regression models were performed to compare HOMA-IR, HOMA-%β, and ISIcomposite among individuals with normal glucose tolerance (NGT) (n=191) versus isolated IFG (n=136), isolated IGT (n=22), combined IFG/IGT (n=43), and diabetes (n=105). Compared with individuals with NGT (2.9±1.6), HOMA-IR progressively increased in individuals with isolated IFG (4.8±2.7, Psex and BMI, these associations remained unchanged. Whole-body insulin sensitivity as measured by ISIcomposite was significantly lower in individuals with isolated IFG (3.9±2.3, Psex, and BMI, isolated IFG (146.6±80.2) was also significantly associated with a decline in HOMA-%β relative to NGT (P=0.005). This study suggests that differences in the underlying metabolic defects leading to diabetes in Arab Americans with IFG and/or IGT exist and may require different strategies for the prevention of diabetes.

  20. Insulin resistance in therapeutic clinic

    Directory of Open Access Journals (Sweden)

    Anna V. Pashentseva

    2017-09-01

    Full Text Available Today an obesity became the global epidemic striking both children, and adults and represents one of the most important problems of health care worldwide. Excess accumulation of fatty tissue is resulted by insulin resistance and a compensatory hyperinsulinaemia which are the main predictors of development of a diabetes mellitus type 2. Insulin resistance is also one of key links of a pathogenesis of such diseases as cardiovascular pathology, not-alcoholic fatty liver disease, a polycystic ovary syndrome, gestational diabetes and many others. Depression of sensitivity of tissues to insulin can be physiological reaction of an organism to stress factors and pathological process. The endogenic reasons also take part in development of insulin resistance besides factors of the external environment. The role of genetic predisposition, a subclinical inflammation of fatty tissue, thyroid hormones, adipokines and vitamin D in formation of this pathological process is studied. As insulin resistance takes part in a pathogenesis of various diseases, methods of its diagnostics and correction are of great importance in therapeutic practice. At purpose of treatment it is worth giving preference to the drugs which are positively influencing sensitivity of tissues to insulin.

  1. effect of low glycaemic index meals on insulin secretion

    African Journals Online (AJOL)

    DR. AMINU

    2012-12-02

    Dec 2, 2012 ... Chicago, IL, USA). Data was presented as mean plus .... carbohydrate along a longer portion of the small intestine ... insulin secretion despite producing relatively small .... Laaksonen, D E, Lindström, J, Lakka, T.A, Eriksson,.

  2. Possible modulatory effect of endogenous islet catecholamines on insulin secretion

    Directory of Open Access Journals (Sweden)

    Gagliardino Juan J

    2001-10-01

    Full Text Available Abstract Background The possible participation of endogenous islet catecholamines (CAs in the control of insulin secretion was tested. Methods Glucose-induced insulin secretion was measured in the presence of 3-Iodo-L-Tyrosine (MIT, a specific inhibitor of tyrosine-hydroxylase activity, in fresh and precultured islets isolated from normal rats. Incubated islets were also used to measure CAs release in the presence of low and high glucose, and the effect of α2-(yohimbine [Y] and idazoxan [I] and α1-adrenergic antagonists (prazosin [P] and terazosin [T] upon insulin secretion elicited by high glucose. Results Fresh islets incubated with 16.7 mM glucose released significantly more insulin in the presence of 1 μM MIT (6.66 ± 0.39 vs 5.01 ± 0.43 ng/islet/h, p Conclusion Our results suggest that islet-originated CAs directly modulate insulin release in a paracrine manner.

  3. Impaired insulin secretion in the spontaneous diabetes rats.

    Science.gov (United States)

    Kimura, K; Toyota, T; Kakizaki, M; Kudo, M; Takebe, K; Goto, Y

    1982-08-01

    Dynamics of insulin and glucagon secretion were investigated by using a new model of spontaneous diabetes rats produced by the repetition of selective breeding in our laboratories. The perfusion experiments of the pancreas showed that the early phase of insulin secretion to continuous stimulation with glucose was specifically impaired, although the response of the early phase to arginine was preserved. The glucose-induced insulin secretion in the nineth generation (F8) which had a more remarkably impaired glucose tolerance was more reduced than in the sixth generation (F5). No significant difference of glucagon secretion in response to arginine or norepinephrine was noted between the diabetes rats and control ones. The present data indicate that the defective insulin secretion is a primary derangement in a diabetic state of the spontaneous diabetes rat. This defect in the early phase of glucose-induced insulin secretion suggests the specific impairment of the recognition of glucose by the pancreatic beta-cells. The spontaneous diabetes rats are very useful as a model of disease for investigating pathophysiology of non-insulin dependent diabetes mellitus.

  4. Neurotrophin Signaling Is Required for Glucose-Induced Insulin Secretion.

    Science.gov (United States)

    Houtz, Jessica; Borden, Philip; Ceasrine, Alexis; Minichiello, Liliana; Kuruvilla, Rejji

    2016-11-07

    Insulin secretion by pancreatic islet β cells is critical for glucose homeostasis, and a blunted β cell secretory response is an early deficit in type 2 diabetes. Here, we uncover a regulatory mechanism by which glucose recruits vascular-derived neurotrophins to control insulin secretion. Nerve growth factor (NGF), a classical trophic factor for nerve cells, is expressed in pancreatic vasculature while its TrkA receptor is localized to islet β cells. High glucose rapidly enhances NGF secretion and increases TrkA phosphorylation in mouse and human islets. Tissue-specific deletion of NGF or TrkA, or acute disruption of TrkA signaling, impairs glucose tolerance and insulin secretion in mice. We show that internalized TrkA receptors promote insulin granule exocytosis via F-actin reorganization. Furthermore, NGF treatment augments glucose-induced insulin secretion in human islets. These findings reveal a non-neuronal role for neurotrophins and identify a new regulatory pathway in insulin secretion that can be targeted to ameliorate β cell dysfunction. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Influence of Flavonoids on Mechanism of Modulation of Insulin Secretion.

    Science.gov (United States)

    Soares, Juliana Mikaelly Dias; Pereira Leal, Ana Ediléia Barbosa; Silva, Juliane Cabral; Almeida, Jackson R G S; de Oliveira, Helinando Pequeno

    2017-01-01

    The development of alternatives for insulin secretion control in vivo or in vitro represents an important aspect to be investigated. In this direction, natural products have been progressively explored with this aim. In particular, flavonoids are potential candidates to act as insulin secretagogue. To study the influence of flavonoid on overall modulation mechanisms of insulin secretion. The research was conducted in the following databases and platforms: PubMed, Scopus, ISI Web of Knowledge, SciELO, LILACS, and ScienceDirect, and the MeSH terms used for the search were flavonoids, flavones, islets of Langerhans, and insulin-secreting cells. Twelve articles were included and represent the basis of discussion on mechanisms of insulin secretion of flavonoids. Papers in ISI Web of Knowledge were in number of 1, Scopus 44, PubMed 264, ScienceDirect 511, and no papers from LILACS and SciELO databases. According to the literature, the majority of flavonoid subclasses can modulate insulin secretion through several pathways, in an indication that corresponding molecule is a potential candidate for active materials to be applied in the treatment of diabetes. The action of natural products on insulin secretion represents an important investigation topic due to their importance in the diabetes controlIn addition to their typical antioxidant properties, flavonoids contribute to the insulin secretionThe modulation of insulin secretion is induced by flavonoids according to different mechanisms. Abbreviations used: K ATP channels: ATP-sensitive K + channels, GLUT4: Glucose transporter 4, ERK1/2: Extracellular signal-regulated protein kinases 1 and 2, L-VDCCs: L-type voltage-dependent Ca +2 channels, GLUT1: Glucose transporter 1, AMPK: Adenosine monophosphate-activated protein kinase, PTP1B: Protein tyrosine phosphatase 1B, GLUT2: Glucose transporter 2, cAMP: Cyclic adenosine monophosphate, PKA: Protein kinase A, PTK: Protein tyrosine kinase, CaMK II: Ca 2+ /calmodulin

  6. Depressive symptoms, insulin sensitivity and insulin secretion in the RISC cohort study

    NARCIS (Netherlands)

    Bot, M.; Pouwer, F.; de Jonge, P.; Nolan, J.J.; Mari, A.; Højlund, K.; Golay, A.; Balkau, B.; Dekker, J.M.

    2013-01-01

    Aim This study explored the association of depressive symptoms with indices of insulin sensitivity and insulin secretion in a cohort of non-diabetic men and women aged 30 to 64 years. Methods The study population was derived from the 3-year follow-up of the Relationship between Insulin Sensitivity

  7. Depressive symptoms, insulin sensitivity and insulin secretion in the RISC cohort study

    NARCIS (Netherlands)

    Bot, M.; Pouwer, F.; De Jonge, P.; Nolan, J. J.; Mari, A.; Hojlund, K.; Golay, A.; Balkau, B.; Dekker, J. M.

    Aim. This study explored the association of depressive symptoms with indices of insulin sensitivity and insulin secretion in a cohort of non-diabetic men and women aged 30 to 64 years. Methods. The study population was derived from the 3-year follow-up of the Relationship between Insulin Sensitivity

  8. Depressive symptoms, insulin sensitivity and insulin secretion in the RISC cohort study

    DEFF Research Database (Denmark)

    Bot, M; Pouwer, F; De Jonge, P

    2013-01-01

    Sensitivity and Cardiovascular Disease Risk (RISC) study. Presence of significant depressive symptoms was defined as a Center for Epidemiologic Studies Depression Scale (CES-D) score ≥ 16. Standard oral glucose tolerance tests were performed. Insulin sensitivity was assessed with the oral glucose insulin......AIM: This study explored the association of depressive symptoms with indices of insulin sensitivity and insulin secretion in a cohort of non-diabetic men and women aged 30 to 64 years. METHODS: The study population was derived from the 3-year follow-up of the Relationship between Insulin...... sensitivity (OGIS) index. Insulin secretion was estimated using three model-based parameters of insulin secretion (beta-cell glucose sensitivity, the potentiation factor ratio, and beta-cell rate sensitivity). RESULTS: A total of 162 out of 1027 participants (16%) had significant depressive symptoms. Having...

  9. Molecular Mechanisms of Insulin Resistance Development

    Directory of Open Access Journals (Sweden)

    Vsevolod Arsen'evich Tkachuk

    2014-05-01

    Full Text Available Insulin resistance (IR is a phenomenon associated with an impaired ability of insulin to stimulate glucose uptake by target cells and to reduce the blood glucose level. A response increase in insulin secretion by the pancreas and hyperinsulinemia are compensatory reactions of the body. The development of IR leads to the inability of target cells to respond to insulin that results in developing type 2 diabetes mellitus (T2DM and metabolic syndrome. For this reason, the metabolic syndrome is defined in practice as a combination of IR with one or more pathologies such as T2DM, arterial hypertension, dyslipidemia, abdominal obesity, non-alcoholic fatty liver disease, and some others. However, a combination of high blood glucose and insulin levels always serves as its physiological criterion.IR should be considered as a systemic failure of the endocrine regulation in the body. Physiological causes of IR are diverse. The main ones are nutritional overload and accumulation of certain lipids and their metabolites in cells, low physical activity, chronic inflammation and stress of various nature, including oxidative and endoplasmic reticulum stress (impairment of damaged protein degradation in the cell. Recent studies have demonstrated that these physiological mechanisms likely act through a single intracellular scenario. This is the impairment of signal transduction from the insulin receptor to its targets via the negative feedback mechanism in intracellular insulin-dependent signaling cascades.This review describes the physiological and intracellular mechanisms of insulin action and focuses on their abnormalities upon IR development. Finally, feasible trends in early molecular diagnosis and therapy of IR are discussed.

  10. Nutritional Modulation of Insulin Resistance

    Directory of Open Access Journals (Sweden)

    Martin O. Weickert

    2012-01-01

    Full Text Available Insulin resistance has been proposed as the strongest single predictor for the development of Type 2 Diabetes (T2DM. Chronic oversupply of energy from food, together with inadequate physical activity, have been recognized as the most relevant factors leading to overweight, abdominal adiposity, insulin resistance, and finally T2DM. Conversely, energy reduced diets almost invariably to facilitate weight loss and reduce abdominal fat mass and insulin resistance. However, sustained weight loss is generally difficult to achieve, and distinct metabolic characteristics in patients with T2DM further compromise success. Therefore, investigating the effects of modulating the macronutrient composition of isoenergetic diets is an interesting concept that may lead to additional important insights. Metabolic effects of various different dietary concepts and strategies have been claimed, but results from randomized controlled studies and particularly from longer-term-controlled interventions in humans are often lacking. However, some of these concepts are supported by recent research, at least in animal models and short-term studies in humans. This paper provides an update of the current literature regarding the role of nutrition in the modulation of insulin resistance, which includes the discussion of weight-loss-independent metabolic effects of commonly used dietary concepts.

  11. Pathophysiological mechanisms of insulin resistance

    NARCIS (Netherlands)

    Brands, M.

    2013-01-01

    In this thesis we studied pathophysiological mechanisms of insulin resistance in different conditions in humans, i.e. in obesity, during lipid infusions, after hypercaloric feeding, and glucocorticoid treatment. We focused on 3 important hypotheses that are suggested to be implicated in the

  12. Obesity genes and insulin resistance.

    Science.gov (United States)

    Belkina, Anna C; Denis, Gerald V

    2010-10-01

    The exploding prevalence of insulin resistance and Type 2 diabetes (T2D) linked to obesity has become an alarming public health concern. Worldwide, approximately 171 million people suffer from obesity-induced diabetes and public health authorities expect this situation to deteriorate rapidly. An interesting clinical population of 'metabolically healthy but obese' (MHO) cases is relatively protected from T2D and its associated cardiovascular risk. The molecular basis for this protection is not well understood but is likely to involve reduced inflammatory responses. The inflammatory cells and pathways that respond to overnutrition are the primary subject matter for this review. The chance discovery of a genetic mutation in the Brd2 gene, which is located in the class II major histocompatibility complex and makes mice enormously fat but protects them from diabetes, offers revolutionary new insights into the cellular mechanisms that link obesity to insulin resistance and T2D. These Brd2-hypomorphic mice have reduced inflammation in fat that is normally associated with insulin resistance, and resemble MHO patients, suggesting novel therapeutic pathways for obese patients at risk for T2D. Deeper understanding of the functional links between genes that control inflammatory responses to diet-induced obesity is crucial to the development of therapies for obese, insulin-resistant patients.

  13. Molecular mechanism of insulin resistance

    Indian Academy of Sciences (India)

    PRAKASH

    incidence of insulin resistance and type 2 diabetes is ..... 10% SDS-PAGE and then subjected to Western blot analysis with anti-pPDK1, pAkt/Akt or anti-pPKCε antibodies (1:1000). ... in humans, where qualitative and quantitative abnormalities.

  14. Skeletal muscle inflammation and insulin resistance in obesity

    Science.gov (United States)

    Wu, Huaizhu; Ballantyne, Christie M.

    2017-01-01

    Obesity is associated with chronic inflammation, which contributes to insulin resistance and type 2 diabetes mellitus. Under normal conditions, skeletal muscle is responsible for the majority of insulin-stimulated whole-body glucose disposal; thus, dysregulation of skeletal muscle metabolism can strongly influence whole-body glucose homeostasis and insulin sensitivity. Increasing evidence suggests that inflammation occurs in skeletal muscle in obesity and is mainly manifested by increased immune cell infiltration and proinflammatory activation in intermyocellular and perimuscular adipose tissue. By secreting proinflammatory molecules, immune cells may induce myocyte inflammation, adversely regulate myocyte metabolism, and contribute to insulin resistance via paracrine effects. Increased influx of fatty acids and inflammatory molecules from other tissues, particularly visceral adipose tissue, can also induce muscle inflammation and negatively regulate myocyte metabolism, leading to insulin resistance. PMID:28045398

  15. Insulin resistance in obesity can be reliably identified from fasting plasma insulin

    NARCIS (Netherlands)

    ter Horst, K. W.; Gilijamse, P. W.; Koopman, K. E.; de Weijer, B. A.; Brands, M.; Kootte, R. S.; Romijn, J. A.; Ackermans, M. T.; Nieuwdorp, M.; Soeters, M. R.; Serlie, M. J.

    2015-01-01

    Insulin resistance is the major contributor to cardiometabolic complications of obesity. We aimed to (1) establish cutoff points for insulin resistance from euglycemic hyperinsulinemic clamps (EHCs), (2) identify insulin-resistant obese subjects and (3) predict insulin resistance from routinely

  16. A role for SPARC in the moderation of human insulin secretion.

    Directory of Open Access Journals (Sweden)

    Lorna W Harries

    Full Text Available AIMS/HYPOTHESIS: We have previously shown the implication of the multifunctional protein SPARC (Secreted protein acidic and rich in cysteine/osteonectin in insulin resistance but potential effects on beta-cell function have not been assessed. We therefore aimed to characterise the effect of SPARC on beta-cell function and features of diabetes. METHODS: We measured SPARC expression by qRT-PCR in human primary pancreatic islets, adipose tissue, liver and muscle. We then examined the relation of SPARC with glucose stimulated insulin secretion (GSIS in primary human islets and the effect of SPARC overexpression on GSIS in beta cell lines. RESULTS: SPARC was expressed at measurable levels in human islets, adipose tissue, liver and skeletal muscle, and demonstrated reduced expression in primary islets from subjects with diabetes compared with controls (p< = 0.05. SPARC levels were positively correlated with GSIS in islets from control donors (p< = 0.01. Overexpression of SPARC in cultured beta-cells resulted in a 2.4-fold increase in insulin secretion in high glucose conditions (p< = 0.01. CONCLUSIONS: Our data suggest that levels of SPARC are reduced in islets from donors with diabetes and that it has a role in insulin secretion, an effect which appears independent of SPARC's modulation of obesity-induced insulin resistance in adipose tissue.

  17. Impact of 9 days of bed rest on hepatic and peripheral insulin action, insulin secretion, and whole-body lipolysis in healthy young male offspring of patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Alibegovic, Amra C; Højbjerre, Lise; Sonne, Mette P

    2009-01-01

    decrease in whole-body insulin sensitivity in both groups. Hepatic insulin resistance was elevated in FDR subjects prior to bed rest and was significantly augmented by bed rest in FDR (P ... deteriorates with 9 days of bed rest, converging toward similar degrees of whole-body insulin resistance. FDR subjects exhibit hepatic insulin resistance (HIR), which, in contrast to CON subjects, deteriorates in response to physical inactivity. FDR subjects exhibit reduced insulin secretion when seen...... subjects, with no significant differences between the groups. Insulin resistance induced by bed rest was fully accounted for by the impairment of nonoxidative glucose metabolism in both groups (overall P resistant FDR and healthy CON subjects...

  18. Microvascular Recruitment in Insulin Resistance

    DEFF Research Database (Denmark)

    Sjøberg, Kim Anker

    the resonating sound from the microbubbles in the systemic circulation were recorded for determination of microvascular recruitment in designated muscle segments. Results showed that microvascular recruitment increased with insulin stimulation by ~30% in rats and ~40% in humans (study I). Furthermore......, it was observed that muscle contractions increased muscle perfusion rapidly by 3-4 fold and by 1-2 fold compared to basal and insulin, respectively, in both rat and human skeletal muscle (study I). The real-time contrast-enhanced ultrasound method was applied to investigate the vaso-active effect of the incretin...... hormone glucagon-like-peptide-1 (GLP-1) in the microcirculation. Glucagon-like-peptide-1 analogs are drugs used for treatments of insulin resistance and type 2 diabetes but the vascular effects of GLP-1 in vivo are elusive. Here it was shown that GLP-1 rapidly increased the microvascular recruitment...

  19. Effect of Avocado Soybean Unsaponifiables on Insulin Secretion and Insulin Sensitivity in Patients with Obesity

    Directory of Open Access Journals (Sweden)

    Esperanza Martínez-Abundis

    2013-10-01

    Full Text Available Aim: To evaluate the effect of avocado soybean unsaponifiables (ASU on insulin secretion and insulin sensitivity in patients with obesity. Methods: A randomized, double-blind, placebo-controlled, clinical trial was carried out in 14 obese adult volunteers. After random allocation of the intervention, 7 patients received 300 mg of ASU or placebo during a fasting state for 3 months. A metabolic profile including IL-6 and high-sensitivity C-reactive protein (hs-CRP levels was carried out prior to the intervention. A hyperglycemic-hyperinsulinemic clamp technique was used to assess insulin secretion and insulin sensitivity phases. Mann-Whitney U test and Wilcoxon test were performed for statistical analyses. The study was approved by the local ethics committee of our institution. Results: At baseline, both groups were similar according to clinical and laboratory characteristics. There was no significant difference in insulin secretion and insulin sensitivity with ASU. Conclusions: ASU administration for 3 months did not modify insulin secretion and insulin sensitivity in patients with obesity.

  20. Using Glucose Tolerance Tests to Model Insulin Secretion and Clearance

    Directory of Open Access Journals (Sweden)

    Anthony Shannon

    2005-04-01

    Full Text Available The purpose of the studies described in this paper is to develop theoretically and to validate experimentally mathematical compartment models which can be used to predict plasma insulin levels in patients with diabetes mellitus (DM. In the case of Type 2 Diabetes Mellitus (T2DM, the C-peptide levels in the plasma were measured as part of routine glucose tolerance tests in order to estimate the prehepatic insulin secretion rates. In the case of Type 1 Diabetes Mellitus (T1DM, a radioactive labelled insulin was used to measure the absorption rate of insulin after a subcutaneous injection of insulin. Both models gave close fits between theoretical estimates and experimental data, and, unlike other models, it is not necessary to seed these models with initial estimates.

  1. Insulin resistance and bone: a biological partnership.

    Science.gov (United States)

    Conte, Caterina; Epstein, Solomon; Napoli, Nicola

    2018-04-01

    Despite a clear association between type 2 diabetes (T2D) and fracture risk, the pathogenesis of bone fragility in T2D has not been clearly elucidated. Insulin resistance is the primary defect in T2D. Insulin signalling regulates both bone formation and bone resorption, but whether insulin resistance can affect bone has not been established. On the other hand, evidence exists that bone might play a role in the regulation of glucose metabolism. This article reviews the available experimental and clinical evidence on the interplay between bone and insulin resistance. Interestingly, a bilateral relationship between bone and insulin resistance seems to exist that unites them in a biological partnership.

  2. Mechanisms of insulin resistance in obesity

    Science.gov (United States)

    Ye, Jianping

    2014-01-01

    Obesity increases the risk for type 2 diabetes through induction of insulin resistance. Treatment of type 2 diabetes has been limited by little translational knowledge of insulin resistance although there have been several well-documented hypotheses for insulin resistance. In those hypotheses, inflammation, mitochondrial dysfunction, hyperinsulinemia and lipotoxicity have been the major concepts and have received a lot of attention. Oxidative stress, endoplasmic reticulum (ER) stress, genetic background, aging, fatty liver, hypoxia and lipodystrophy are active subjects in the study of these concepts. However, none of those concepts or views has led to an effective therapy for type 2 diabetes. The reason is that there has been no consensus for a unifying mechanism of insulin resistance. In this review article, literature is critically analyzed and reinterpreted for a new energy-based concept of insulin resistance, in which insulin resistance is a result of energy surplus in cells. The energy surplus signal is mediated by ATP and sensed by adenosine monophosphate-activated protein kinase (AMPK) signaling pathway. Decreasing ATP level by suppression of production or stimulation of utilization is a promising approach in the treatment of insulin resistance. In support, many of existing insulin sensitizing medicines inhibit ATP production in mitochondria. The effective therapies such as weight loss, exercise, and caloric restriction all reduce ATP in insulin sensitive cells. This new concept provides a unifying cellular and molecular mechanism of insulin resistance in obesity, which may apply to insulin resistance in aging and lipodystrophy. PMID:23471659

  3. Effect of alcohol on insulin secretion and viability of human pancreatic islets

    Directory of Open Access Journals (Sweden)

    Nikolić Dragan

    2017-01-01

    Full Text Available Introduction/Objective. There are controversial data in the literature on the topic of effects of alcohol on insulin secretion, apoptosis, and necrosis of the endocrine and exocrine pancreas. The goal of this research was to determine how alcohol affects the insulin secretion and viability of human adult pancreatic islets in vitro during a seven-day incubation. Methods. Human pancreatic tissue was digested with Collagenase XI, using a non-automated method. Cultures were incubated in Roswell Park Memorial Institute (RPMI medium containing alcohol (10 μl of alcohol in 100 ml of medium. Insulin stimulation index (SI and viability of the islets were determined on the first, third, and seventh day of cultivation. Results. Analysis of the viability of the islets showed that there wasn’t significant difference between the control and the test group. In the test group, viability of the cultures declined with the time of incubation. SI of the test group was higher compared to the control group, by 50% and 25% on the first and third day of cultivation, respectively. On the seventh day, insulin secretion was reduced by 25%. The difference was not statistically significant (p > 0.05. In the test group, significant decline in insulin secretion was found on the third and seventh day of incubation (p ≤ 0.05. Conclusion. Alcohol can increase or decrease insulin secretion of islets cultures, which may result in an inadequate response of pancreatic β-cells to blood glucose, leading to insulin resistance, and increased risk of developing type 2 diabetes. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 41002

  4. Metabolic surgery for non-obese type 2 diabetes: incretins, adipocytokines, and insulin secretion/resistance changes in a 1-year interventional clinical controlled study.

    Science.gov (United States)

    Geloneze, Bruno; Geloneze, Sylka Rodovalho; Chaim, Elinton; Hirsch, Fernanda Filgueira; Felici, Ana Claudia; Lambert, Giselle; Tambascia, Marcos Antonio; Pareja, José Carlos

    2012-07-01

    To compare duodenal-jejunal bypass (DJB) with standard medical care in nonobese patients with type 2 diabetes and evaluate surgically induced endocrine and metabolic changes. Eighteen patients submitted to a DJB procedure met the following criteria: overweight, diabetes diagnosis less than 15 years, current insulin treatment, residual β-cell function, and absence of autoimmunity. Patients who refused surgical treatment received standard medical care (control group). At baseline, 3, 6, and 12 months after surgery, insulin sensitivity and production of glucagon-like peptide-1 and glucose-insulinotropic polypeptide were assessed during a meal tolerance test. Fasting adipocytokines and dipeptidyl-peptidase-4 concentrations were measured. The mean age of the patients was 50 (5) years, time of diagnosis: 9 (2) years, time of insulin usage: 6 (5) months, fasting glucose: 9.9 (2.5) mmol/dL, and HbA1c (glycosylated hemoglobin) level: 8.9% (1.2%). Duodenal-jejunal bypass group showed greater reductions in fasting glucose (22% vs 6% in control group, P < 0.05) and daily insulin requirement (93% vs 15%, P < 0.01). Twelve patients from DJB group stopped using insulin and showed improvements in insulin sensitivity and β-cell function (P < 0.01), and reductions in glucose-insulinotropic polypeptide levels (P < 0.001), glucagon during the first 30 minutes after meal (P < 0.05), and leptin levels (P < 0.05). Dipeptidyl-peptidase-4 levels increased after surgery (P < 0.01), but glucagon-like peptide-1 levels did not change. Duodenal-jejunal bypass improved insulin sensitivity and β-cell function and reduced glucose-insulinotropic polypeptide, leptin, and glucagon production. Hence, DJB resulted in better glycemic control and reduction in insulin requirement but DJB did not result in remission of diabetes.

  5. Streptozotocin diabetes and insulin resistance impairment of ...

    African Journals Online (AJOL)

    ... insulin resistance impairment of spermatogenesis in adult rat testis: Central Vs local ... Summary: Mammalian reproduction is dynamically regulated by the pituitary ... Group 3 > Streptozotocin-insulin treated group; received a single dose IP ...

  6. Methylated trivalent arsenicals are potent inhibitors of glucose stimulated insulin secretion by murine pancreatic islets

    Energy Technology Data Exchange (ETDEWEB)

    Douillet, Christelle [Department of Nutrition, Gillings School of Global Public Health, 2302 MHRC, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7461 (United States); Currier, Jenna [Curriculum in Toxicology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7461 (United States); Saunders, Jesse [Department of Nutrition, Gillings School of Global Public Health, 2302 MHRC, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7461 (United States); Bodnar, Wanda M. [Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7431 (United States); Matoušek, Tomáš [Institute of Analytical Chemistry of the ASCR, v.v.i., Veveří 97, 602 00 Brno (Czech Republic); Stýblo, Miroslav, E-mail: styblo@med.unc.edu [Department of Nutrition, Gillings School of Global Public Health, 2302 MHRC, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7461 (United States)

    2013-02-15

    Epidemiologic evidence has linked chronic exposure to inorganic arsenic (iAs) with an increased prevalence of diabetes mellitus. Laboratory studies have identified several mechanisms by which iAs can impair glucose homeostasis. We have previously shown that micromolar concentrations of arsenite (iAs{sup III}) or its methylated trivalent metabolites, methylarsonite (MAs{sup III}) and dimethylarsinite (DMAs{sup III}), inhibit the insulin-activated signal transduction pathway, resulting in insulin resistance in adipocytes. Our present study examined effects of the trivalent arsenicals on insulin secretion by intact pancreatic islets isolated from C57BL/6 mice. We found that 48-hour exposures to low subtoxic concentrations of iAs{sup III}, MAs{sup III} or DMAs{sup III} inhibited glucose-stimulated insulin secretion (GSIS), but not basal insulin secretion. MAs{sup III} and DMAs{sup III} were more potent than iAs{sup III} as GSIS inhibitors with estimated IC{sub 50} ≤ 0.1 μM. The exposures had little or no effects on insulin content of the islets or on insulin expression, suggesting that trivalent arsenicals interfere with mechanisms regulating packaging of the insulin transport vesicles or with translocation of these vesicles to the plasma membrane. Notably, the inhibition of GSIS by iAs{sup III}, MAs{sup III} or DMAs{sup III} could be reversed by a 24-hour incubation of the islets in arsenic-free medium. These results suggest that the insulin producing pancreatic β-cells are among the targets for iAs exposure and that the inhibition of GSIS by low concentrations of the methylated metabolites of iAs may be the key mechanism of iAs-induced diabetes. - Highlights: ► Trivalent arsenicals inhibit glucose stimulated insulin secretion by pancreatic islets. ► MAs{sup III} and DMAs{sup III} are more potent inhibitors than arsenite with IC{sub 50} ∼ 0.1 μM. ► The arsenicals have little or no effects on insulin expression in pancreatic islets. ► The inhibition of

  7. Methylated trivalent arsenicals are potent inhibitors of glucose stimulated insulin secretion by murine pancreatic islets

    International Nuclear Information System (INIS)

    Douillet, Christelle; Currier, Jenna; Saunders, Jesse; Bodnar, Wanda M.; Matoušek, Tomáš; Stýblo, Miroslav

    2013-01-01

    Epidemiologic evidence has linked chronic exposure to inorganic arsenic (iAs) with an increased prevalence of diabetes mellitus. Laboratory studies have identified several mechanisms by which iAs can impair glucose homeostasis. We have previously shown that micromolar concentrations of arsenite (iAs III ) or its methylated trivalent metabolites, methylarsonite (MAs III ) and dimethylarsinite (DMAs III ), inhibit the insulin-activated signal transduction pathway, resulting in insulin resistance in adipocytes. Our present study examined effects of the trivalent arsenicals on insulin secretion by intact pancreatic islets isolated from C57BL/6 mice. We found that 48-hour exposures to low subtoxic concentrations of iAs III , MAs III or DMAs III inhibited glucose-stimulated insulin secretion (GSIS), but not basal insulin secretion. MAs III and DMAs III were more potent than iAs III as GSIS inhibitors with estimated IC 50 ≤ 0.1 μM. The exposures had little or no effects on insulin content of the islets or on insulin expression, suggesting that trivalent arsenicals interfere with mechanisms regulating packaging of the insulin transport vesicles or with translocation of these vesicles to the plasma membrane. Notably, the inhibition of GSIS by iAs III , MAs III or DMAs III could be reversed by a 24-hour incubation of the islets in arsenic-free medium. These results suggest that the insulin producing pancreatic β-cells are among the targets for iAs exposure and that the inhibition of GSIS by low concentrations of the methylated metabolites of iAs may be the key mechanism of iAs-induced diabetes. - Highlights: ► Trivalent arsenicals inhibit glucose stimulated insulin secretion by pancreatic islets. ► MAs III and DMAs III are more potent inhibitors than arsenite with IC 50 ∼ 0.1 μM. ► The arsenicals have little or no effects on insulin expression in pancreatic islets. ► The inhibition of insulin secretion by arsenite, MAs III or DMAs III is reversible. ► Thus

  8. Pathogenesis of Insulin Resistance in Skeletal Muscle

    Directory of Open Access Journals (Sweden)

    Muhammad A. Abdul-Ghani

    2010-01-01

    Full Text Available Insulin resistance in skeletal muscle is manifested by decreased insulin-stimulated glucose uptake and results from impaired insulin signaling and multiple post-receptor intracellular defects including impaired glucose transport, glucose phosphorylation, and reduced glucose oxidation and glycogen synthesis. Insulin resistance is a core defect in type 2 diabetes, it is also associated with obesity and the metabolic syndrome. Dysregulation of fatty acid metabolism plays a pivotal role in the pathogenesis of insulin resistance in skeletal muscle. Recent studies have reported a mitochondrial defect in oxidative phosphorylation in skeletal muscle in variety of insulin resistant states. In this review, we summarize the cellular and molecular defects that contribute to the development of insulin resistance in skeletal muscle.

  9. Decreased insulin secretion in pregnant rats fed a low protein diet.

    Science.gov (United States)

    Gao, Haijun; Ho, Eric; Balakrishnan, Meena; Yechoor, Vijay; Yallampalli, Chandra

    2017-10-01

    Low protein (LP) diet during pregnancy leads to reduced plasma insulin levels in rodents, but the underlying mechanisms remain unclear. Glucose is the primary insulin secretagogue, and enhanced glucose-stimulated insulin secretion (GSIS) in beta cells contributes to compensation for insulin resistance and maintenance of glucose homeostasis during pregnancy. In this study, we hypothesized that plasma insulin levels in pregnant rats fed LP diet are reduced due to disrupted GSIS of pancreatic islets. We first confirmed reduced plasma insulin levels, then investigated in vivo insulin secretion by glucose tolerance test and ex vivo GSIS of pancreatic islets in the presence of glucose at different doses, and KCl, glibenclamide, and L-arginine. Main findings include (1) plasma insulin levels were unaltered on day 10, but significantly reduced on days 14-22 of pregnancy in rats fed LP diet compared to those of control (CT) rats; (2) insulin sensitivity was unchanged, but glucose intolerance was more severe in pregnant rats fed LP diet; (3) GSIS in pancreatic islets was lower in LP rats compared to CT rats in the presence of glucose, KCl, and glibenclamide, and the response to L-arginine was abolished in LP rats; and (4) the total insulin content in pancreatic islets and expression of Ins2 were reduced in LP rats, but expression of Gcg was unaltered. These studies demonstrate that decreased GSIS in beta cells of LP rats contributes to reduced plasma insulin levels, which may lead to placental and fetal growth restriction and programs hypertension and other metabolic diseases in offspring. © The Authors 2017. Published by Oxford University Press on behalf of Society for the Study of Reproduction. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Altered pancreatic growth and insulin secretion in WSB/EiJ mice.

    Directory of Open Access Journals (Sweden)

    Maggie M Ho

    Full Text Available These data suggest that insulin secretion in WSB mice is blunted specifically in vivo, either due to a reduced insulin requirement and/or due to factors that are absent or destroyed in vitro. These studies also highlight the role of post-natal growth in determining adult β-cell mass. Mice are important animal models for the study of metabolic physiology and the genetics of complex traits. Wild-derived inbred mouse strains, such as WSB/EiJ (WSB, are unrelated to the commonly studied mouse strains and are valuable tools to identify novel genes that modify disease risk. We have previously shown that in contrast to C57BL/6J (B6 mice, WSB mice fed a high fat diet do not develop hyperinsulinemia or insulin resistance, and had nearly undetectable insulin secretion in response to an intraperitoneal glucose challenge. As hyperinsulinemia may drive obesity and insulin resistance, we examined whether defects in β-cell mass or function could contribute to the low insulin levels in WSB mice. In young WSB mice, β-cell mass was similar to B6 mice. However, we found that adult WSB mice had reduced β-cell mass due to reduced pancreatic weights. Pancreatic sizes were similar between the strains when normalized to body weight, suggesting their pancreatic size is appropriate to their body size in adults, but overall post-natal pancreatic growth was reduced in WSB mice compared to B6 mice. Islet architecture was normal in WSB mice. WSB mice had markedly increased insulin secretion from isolated islets in vitro. These data suggest that insulin secretion in WSB mice is blunted specifically in vivo, either due to a reduced insulin requirement and/or due to factors that are absent or destroyed in vitro. These studies suggest that WSB mice may provide novel insight into mechanisms regulating insulin secretion and also highlight the role of post-natal growth in determining adult β-cell mass.

  11. Insulin-like growth factor-1 is a negative modulator of glucagon secretion

    OpenAIRE

    Mancuso, Elettra; Mannino, Gaia C.; Fatta, Concetta Di; Fuoco, Anastasia; Spiga, Rosangela; Andreozzi, Francesco; Sesti, Giorgio

    2017-01-01

    Glucagon secretion involves a combination of paracrine, autocrine, hormonal, and autonomic neural mechanisms. Type 2 diabetes often presents impaired glucagon suppression by insulin and glucose. Insulin-like growth factor-I (IGF-1) has elevated homology with insulin, and regulates pancreatic ?-cells insulin secretion. Insulin and IGF-1 receptors share considerable structure homology and function. We hypothesized the existence of a mechanism linking the inhibition of ?-cells glucagon secretion...

  12. Insulin and insulin signaling play a critical role in fat induction of insulin resistance in mouse

    Science.gov (United States)

    Ning, Jie; Hong, Tao; Yang, Xuefeng; Mei, Shuang; Liu, Zhenqi; Liu, Hui-Yu

    2011-01-01

    The primary player that induces insulin resistance has not been established. Here, we studied whether or not fat can cause insulin resistance in the presence of insulin deficiency. Our results showed that high-fat diet (HFD) induced insulin resistance in C57BL/6 (B6) mice. The HFD-induced insulin resistance was prevented largely by the streptozotocin (STZ)-induced moderate insulin deficiency. The STZ-induced insulin deficiency prevented the HFD-induced ectopic fat accumulation and oxidative stress in liver and gastrocnemius. The STZ-induced insulin deficiency prevented the HFD- or insulin-induced increase in hepatic expression of long-chain acyl-CoA synthetases (ACSL), which are necessary for fatty acid activation. HFD increased mitochondrial contents of long-chain acyl-CoAs, whereas it decreased mitochondrial ADP/ATP ratio, and these HFD-induced changes were prevented by the STZ-induced insulin deficiency. In cultured hepatocytes, we observed that expressions of ACSL1 and -5 were stimulated by insulin signaling. Results in cultured cells also showed that blunting insulin signaling by the PI3K inhibitor LY-294002 prevented fat accumulation, oxidative stress, and insulin resistance induced by the prolonged exposure to either insulin or oleate plus sera that normally contain insulin. Finally, knockdown of the insulin receptor prevented the oxidative stress and insulin resistance induced by the prolonged exposure to insulin or oleate plus sera. Together, our results show that insulin and insulin signaling are required for fat induction of insulin resistance in mice and cultured mouse hepatocytes. PMID:21586696

  13. Trehalose prevents adipocyte hypertrophy and mitigates insulin resistance.

    Science.gov (United States)

    Arai, Chikako; Arai, Norie; Mizote, Akiko; Kohno, Keizo; Iwaki, Kanso; Hanaya, Toshiharu; Arai, Shigeyuki; Ushio, Simpei; Fukuda, Shigeharu

    2010-12-01

    Trehalose has been shown to evoke lower insulin secretion than glucose in oral saccharide tolerance tests in humans. Given this hypoinsulinemic effect of trehalose, we hypothesized that trehalose suppresses adipocyte hypertrophy by reducing storage of triglyceride and mitigates insulin resistance in mice fed a high-fat diet (HFD). Mice were fed an HFD and given drinking water containing 2.5% saccharide (glucose [Glc], trehalose [Tre], maltose [Mal], high-fructose corn syrup, or fructose [Fru]) ad libitum. After 7 weeks of HFD and saccharide intake, fasting serum insulin levels in the Tre/HFD group were significantly lower than in the Mal/HFD and Glc/HFD groups (P fructose corn syrup/HFD, or Fru/HFD group. Analysis of gene expression in mesenteric adipocytes showed that no statistically significant difference in the expression of monocyte chemoattractant protein-1 (MCP-1) messenger RNA (mRNA) was observed between the Tre/HFD group and the distilled water/standard diet group, whereas a significant increase in the MCP-1 mRNA expression was observed in the Glc/HFD, Mal/HFD, Fru/HFD, and distilled water/HFD groups. Thus, our data indicate that trehalose prevents adipocyte hypertrophy and mitigates insulin resistance in HFD-fed mice by reducing insulin secretion and down-regulating mRNA expression of MCP-1. These findings further suggest that trehalose is a functional saccharide that mitigates insulin resistance. Copyright © 2010 Elsevier Inc. All rights reserved.

  14. Associations between depressive symptoms and insulin resistance

    DEFF Research Database (Denmark)

    Adriaanse, M C; Dekker, J M; Nijpels, G

    2006-01-01

    AIMS/HYPOTHESIS: The association between depression and insulin resistance has been investigated in only a few studies, with contradictory results reported. The aim of this study was to determine whether the association between symptoms of depression and insulin resistance varies across glucose...... established type 2 diabetes mellitus. Main outcome measures were insulin resistance defined by the homeostasis model assessment for insulin resistance (HOMA-IR) and symptoms of depression using the Centre for Epidemiologic Studies Depression Scale (CES-D). RESULTS: In the total sample, we found a weak.......942). The association between depressive symptoms and insulin resistance was similar for men and women. CONCLUSIONS/INTERPRETATION: We found only weak associations between depressive symptoms and insulin resistance, which did not differ among different glucose metabolism subgroups or between men and women....

  15. Importance of radioimmunoassay of insulin secretion disorder as atherogenic factor

    Energy Technology Data Exchange (ETDEWEB)

    Knyazev, Yu A; Bespalova, V A; Vakhrusheva, L L; Kirbasova, N P; Severtseva, V V

    1984-11-01

    Using a radioimmunoassay a C-peptide levei was revealed in children, pregnant and lying-in women as well as in patients with insulin-dependent diabetes mellitus. After breakfast and insulin administration wich curative purposes the IRI concentration in children increased whereas the C-peptide level changed insignificantly. Changes of the insulin secretion were more noticeable in severe diabetes mejlitus with vascular complications and in disease decompensation. The atherogenic nature of the lipid metaboiism (an increase in the cholesterol, triglyceride and ..beta..-lipoprotein levels), changes in the liver and tendency to vascular involvement are results of insulin effect inadequacy. Such metabolic derangements in pregnant women create unfavorable conditions for the development of fetus and may lead to early atherogenic processes.

  16. A Unifying Organ Model of Pancreatic Insulin Secretion.

    Directory of Open Access Journals (Sweden)

    Andrea De Gaetano

    Full Text Available The secretion of insulin by the pancreas has been the object of much attention over the past several decades. Insulin is known to be secreted by pancreatic β-cells in response to hyperglycemia: its blood concentrations however exhibit both high-frequency (period approx. 10 minutes and low-frequency oscillations (period approx. 1.5 hours. Furthermore, characteristic insulin secretory response to challenge maneuvers have been described, such as frequency entrainment upon sinusoidal glycemic stimulation; substantial insulin peaks following minimal glucose administration; progressively strengthened insulin secretion response after repeated administration of the same amount of glucose; insulin and glucose characteristic curves after Intra-Venous administration of glucose boli in healthy and pre-diabetic subjects as well as in Type 2 Diabetes Mellitus. Previous modeling of β-cell physiology has been mainly directed to the intracellular chain of events giving rise to single-cell or cell-cluster hormone release oscillations, but the large size, long period and complex morphology of the diverse responses to whole-body glucose stimuli has not yet been coherently explained. Starting with the seminal work of Grodsky it was hypothesized that the population of pancreatic β-cells, possibly functionally aggregated in islets of Langerhans, could be viewed as a set of independent, similar, but not identical controllers (firing units with distributed functional parameters. The present work shows how a single model based on a population of independent islet controllers can reproduce very closely a diverse array of actually observed experimental results, with the same set of working parameters. The model's success in reproducing a diverse array of experiments implies that, in order to understand the macroscopic behaviour of the endocrine pancreas in regulating glycemia, there is no need to hypothesize intrapancreatic pacemakers, influences between different

  17. Histone deacetylase 3 inhibition improves glycaemia and insulin secretion in obese diabetic rats

    DEFF Research Database (Denmark)

    Lundh, Morten; Galbo, Thomas; Poulsen, Steen Seier

    2015-01-01

    Failure of pancreatic β cells to compensate for insulin resistance is a prerequisite for the development of type 2 diabetes. Sustained elevated circulating levels of free fatty acids and glucose contribute to β-cell failure. Selective inhibition of Histone deacetylase (HDAC)-3 protects pancreatic β...... cells against inflammatory and metabolic insults in vitro. Here we tested the ability of a selective HDAC3 inhibitor, BRD3308, to reduce hyperglycemia and increase insulin secretion in an animal model of type 2 diabetes. At diabetes onset, an ambulatory hyperglycemic clamp was performed. HDAC3......3 as a key therapeutic target for β-cell protection in type 2 diabetes....

  18. Specific insulin and proinsulin secretion in glucokinase-deficient individuals

    Directory of Open Access Journals (Sweden)

    V.C. Pardini

    1999-04-01

    Full Text Available Glucokinase (GCK is an enzyme that regulates insulin secretion, keeping glucose levels within a narrow range. Mutations in the glucokinase gene cause a rare form of diabetes called maturity-onset diabetes of the young (MODY. An early onset (less than 25 years, autosomal dominant inheritance and low insulin secretion stimulated by glucose characterize MODY patients. Specific insulin and proinsulin were measured in serum by immunofluorimetric assays (IFMA during a 75-g oral glucose tolerance test (OGTT. Two kindreds (SA and LZ were studied and compared to non-diabetic unrelated individuals (control group 1 matched for age and body mass index (BMI. In one kindred, some of these subjects were also obese (BMI >26 kg/m2, and other family members also presented with obesity and/or late-onset NIDDM. The MODY patients were also compared to a group of five of their first-degree relatives with obesity and/or late-onset NIDDM. The proinsulin profile was different in members of the two MODY kindreds. Fasting proinsulin and the proinsulin/insulin ratio were similar in MODY members of kindred LZ and subjects from control group 1, but were significantly lower than in MODY members of kindred SA (P<0.02 and P<0.01, for proinsulin and proinsulin/insulin ratio, respectively. Moreover, MODY members of family SA had higher levels of proinsulin and proinsulin/insulin ratio, although not significantly different, when compared to their first-degree relatives and to subjects from control group 2. In conclusion, we observed variable degrees of proinsulin levels and proinsulin/insulin ratio in MODY members of two different kindreds. The higher values of these parameters found in MODY and non-MODY members of kindred SA is probably related to the obesity and late-onset NIDDM background present in this family.

  19. Sex differences in insulin resistance in GABAB1 knockout mice.

    Science.gov (United States)

    Bonaventura, M M; Rodriguez, D; Ferreira, M L; Crivello, M; Repetto, E M; Bettler, B; Libertun, C; Lux-Lantos, V A

    2013-02-27

    We have previously demonstrated that the absence of functional GABA B receptors (GABABRs) disturbs glucose homeostasis in GABAB1KO mice. The aim of this work was to extend our studies of these alterations in GABAB1KO mice and investigate the sexual differences therein. Male and female, GABAB1KO and WT mice were used. Glucose and insulin tolerance tests (GTT and ITT), and insulin and glucagon secretion tests (IST and GST) were performed. Blood glucose, serum insulin and hyperglycemic hormones were determined, and HOMA-IR calculated. Skeletal muscle insulin receptor β subunit (IRβ), insulin receptor substrates 1/2 (IRS1, IRS2) and hexokinase-II levels were determined by Western blot. Skeletal muscle insulin sensitivity was assessed by in vivo insulin-induced Akt phosphorylation (Western blot). Food intake and hypothalamic NPY mRNA expression (by qPCR) were also evaluated. Fasted insulin and HOMA-IR were augmented in GABAB1KO males, with no alterations in females. Areas under the curve (AUC) for GTT and ITT were increased in GABAB1KO mice of both genders, indicating compromised insulin sensitivity. No genotype differences were observed in IST, GST or in IRβ, IRS1, IRS2 and hexokinase-II expression. Akt activation was severely impaired in GABAB1KO males while no alterations were observed in females. GABAB1KO mice showed increased food intake and NPY expression. Glucose metabolism and energy balance disruptions were more pronounced in GABAB1KO males, which develop peripheral insulin resistance probably due to augmented insulin secretion. Metabolic alterations in females were milder and possibly due to previously described reproductive disorders, such as persistent estrus. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Induction of insulin secretion in engineered liver cells by nitric oxide

    Directory of Open Access Journals (Sweden)

    Özcan Sabire

    2007-10-01

    Full Text Available Abstract Background Type 1 Diabetes Mellitus results from an autoimmune destruction of the pancreatic beta cells, which produce insulin. The lack of insulin leads to chronic hyperglycemia and secondary complications, such as cardiovascular disease. The currently approved clinical treatments for diabetes mellitus often fail to achieve sustained and optimal glycemic control. Therefore, there is a great interest in the development of surrogate beta cells as a treatment for type 1 diabetes. Normally, pancreatic beta cells produce and secrete insulin only in response to increased blood glucose levels. However in many cases, insulin secretion from non-beta cells engineered to produce insulin occurs in a glucose-independent manner. In the present study we engineered liver cells to produce and secrete insulin and insulin secretion can be stimulated via the nitric oxide pathway. Results Expression of either human insulin or the beta cell specific transcription factors PDX-1, NeuroD1 and MafA in the Hepa1-6 cell line or primary liver cells via adenoviral gene transfer, results in production and secretion of insulin. Although, the secretion of insulin is not significantly increased in response to high glucose, treatment of these engineered liver cells with L-arginine stimulates insulin secretion up to three-fold. This L-arginine-mediated insulin release is dependent on the production of nitric oxide. Conclusion Liver cells can be engineered to produce insulin and insulin secretion can be induced by treatment with L-arginine via the production of nitric oxide.

  1. Selective Insulin Resistance in the Kidney

    Science.gov (United States)

    Horita, Shoko; Nakamura, Motonobu; Suzuki, Masashi; Satoh, Nobuhiko; Suzuki, Atsushi; Seki, George

    2016-01-01

    Insulin resistance has been characterized as attenuation of insulin sensitivity at target organs and tissues, such as muscle and fat tissues and the liver. The insulin signaling cascade is divided into major pathways such as the PI3K/Akt pathway and the MAPK/MEK pathway. In insulin resistance, however, these pathways are not equally impaired. For example, in the liver, inhibition of gluconeogenesis by the insulin receptor substrate (IRS) 2 pathway is impaired, while lipogenesis by the IRS1 pathway is preserved, thus causing hyperglycemia and hyperlipidemia. It has been recently suggested that selective impairment of insulin signaling cascades in insulin resistance also occurs in the kidney. In the renal proximal tubule, insulin signaling via IRS1 is inhibited, while insulin signaling via IRS2 is preserved. Insulin signaling via IRS2 continues to stimulate sodium reabsorption in the proximal tubule and causes sodium retention, edema, and hypertension. IRS1 signaling deficiency in the proximal tubule may impair IRS1-mediated inhibition of gluconeogenesis, which could induce hyperglycemia by preserving glucose production. In the glomerulus, the impairment of IRS1 signaling deteriorates the structure and function of podocyte and endothelial cells, possibly causing diabetic nephropathy. This paper mainly describes selective insulin resistance in the kidney, focusing on the proximal tubule. PMID:27247938

  2. [Changes in the secretion of somatotropin and insulin in hyperthyroidism].

    Science.gov (United States)

    Cavagnini, F; Peracchi, M; Panerai, A E; Pinto, M

    1975-06-01

    Twenty hyperthyroid patients were investigated for growth hormone (GH) and immunoreactive insulin (IRI) secretion in response to insulin hypoglycaemia, arginine infusion and glucose-induced hyperglycaemia. GH response to either insulin hypoglycaemia or arginine infusion was significantly reduced in these patients compared with 20 normal subjects. Thyrotoxic patients also displayed an abnormal GH pattern after a 100 g oral glucose load: in fact, serum GH underwent a paradoxical increase in spite of abnormally high levels attained by blood glucose. IRI secretion was also clearly reduced in response to arginine infusion and moderately blunted after oral glucose. In a group of patients re-evaluated under euthyroid conditions, a fair increase of GH response to the provocative stimuli jointly with the restoration of a normal suppressibility of serum GH by glucose were noted; by contrast, no significant change of IRI response to arginine or glucose took place. Likewise, the impairment of glucose tolerance was not improved. These findings indicate that an impairment of GH and IRI secretion is present in hyperthyroidism. The possibility that a potentiation of the catecholamine effects caused by the thyroid hormones is involved in this alteration deserves consideration.

  3. Association between omentin levels and insulin resistance in pregnancy.

    Science.gov (United States)

    Aktas, G; Alcelik, A; Ozlu, T; Tosun, M; Tekce, B K; Savli, H; Tekce, H; Dikbas, O

    2014-03-01

    Omentin is a new adipokine secreted mainly from visceral adipose tissue. Serum omentin is found to be reduced in patients with impaired glucose tolerance, type 2 diabetes mellitus, obesity and insulin resistant states. Despite the fact that pregnancy is also characterized with hyperinsulinemia, literature is lacking about data of omentin levels and its association with insulin resistance in pregnant women. We aimed to evaluate the association of omentin levels and insulin resistance in pregnant women and to compare these levels with those of non-pregnant, non-diabetic women. Uncomplicated pregnant women who admit to our outpatient clinics for routine follow-up were included in the study group. Non-pregnant women without diabetes mellitus were served as control group. Fasting glucose, insulin, omentin levels and HOMA IR were recorded. SPSS 15.0 for Windows was used for statistical analysis. There were 36 pregnant women in the study group and 37 healthy, non-pregnant women in the control group. Serum omentin and fasting glucose levels were significantly decreased and fasting insulin was significantly increased in the study group compared to control group. Omentin might be an indicator of insulin resistance in pregnant women. Larger prospective studies are needed to claim whether omentin can have a clinical use for diagnosis of gestational diabetes mellitus. © J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York.

  4. Insulin resistance, insulin sensitization and inflammation in polycystic ovarian syndrome

    Directory of Open Access Journals (Sweden)

    Dhindsa G

    2004-04-01

    Full Text Available It is estimated that 5-10% of women of reproductive age have polycystic ovarian syndrome (PCOS. While insulin resistance is not part of the diagnostic criteria for PCOS, its importance in the pathogenesis of PCOS cannot be denied. PCOS is associated with insulin resistance independent of total or fat-free body mass. Post-receptor defects in the action of insulin have been described in PCOS which are similar to those found in obesity and type 2 diabetes. Treatment with insulin sensitizers, metformin and thiazolidinediones, improve both metabolic and hormonal patterns and also improve ovulation in PCOS. Recent studies have shown that PCOS women have higher circulating levels of inflammatory mediators like C-reactive protein, tumour necrosis factor- , tissue plasminogen activator and plasminogen activator inhibitor-1 (PAI-1 . It is possible that the beneficial effect of insulin sensitizers in PCOS may be partly due to a decrease in inflammation.

  5. Genetic markers of insulin resistance in gestational diabetes

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    Tatiana Vasil'evna Sebko

    2009-12-01

    Full Text Available Aim. To search for genetic markers of insulin resistance and impaired insulin secretion in pregnant women with gestational diabetes mellitus (GDM. Materials and methods. A total of 100 healthy pregnant women and 185 patients with GDM were available for examination. 80 patients developedGDM during current pregnancy, in 105 it was diagnosed 4-19 years ago. 25 of the 105 GDM patients had a history of type 2 DM. The following parameterswere measured: beta-cell secretory activity (proinsulin, ITI, C-peptide, total cholesterol (CH, HDL and LDL CH, triglycerides, HbA1c,fasting glycemia. Molecular-genetic DNA testing using PCR included studies of KCNJ 11, TCF7L2, PPARG2, ADIPOQ, ADIPOR1, ADIPOR2gene polymorphism. These genes were chosen based on the published data associating them with disturbed insulin secretion and sensitivity in DM2patient. Results. Pregnant women with GDM and obesity showed elevated IRI and leptin levels compared with controls. This rise was accompanied bymarked insulin resistance in 75% of these patients. In 50% of the healthy women proinsulin and insulin secretion decreased. Obesity in pregnantpatients was associated with significant elevation of proinsulin, IRI, and C-peptyide levels and GDM with Lys/Lys genotype of polymorphous markerGlu23k of KCNJ11 gene, pro and ala allele of polymorphous marker A219T of ADIPOR2 gene. These associations suggest specific genetic featuresof GDM related to impaired insulin secretion and sensitivity. Conclusion. Studies of common genetic nature of GDM and DM2 permit to identify risk groups at the preclinical stage, plan prevention and treatmentof these disorders.

  6. Genetics Home Reference: type A insulin resistance syndrome

    Science.gov (United States)

    ... Conditions Type A insulin resistance syndrome Type A insulin resistance syndrome Printable PDF Open All Close All Enable ... view the expand/collapse boxes. Description Type A insulin resistance syndrome is a rare disorder characterized by severe ...

  7. Incretins, insulin secretion and Type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Vilsbøll, Tina; Holst, Jens Møller

    2004-01-01

    the genes encoding their receptors have been deleted. In patients with Type 2 diabetes, the incretin effect is either greatly impaired or absent, and it is assumed that this could contribute to the inability of these patients to adjust their insulin secretion to their needs. In studies of the mechanism...... of the impaired incretin effect in Type 2 diabetic patients, it has been found that the secretion of GIP is generally normal, whereas the secretion of GLP-1 is reduced, presumably as a consequence of the diabetic state. It might be of even greater importance that the effect of GLP-1 is preserved whereas...... the effect of GIP is severely impaired. The impaired GIP effect seems to have a genetic background, but could be aggravated by the diabetic state. The preserved effect of GLP-1 has inspired attempts to treat Type 2 diabetes with GLP-1 or analogues thereof, and intravenous GLP-1 administration has been shown...

  8. Incretins, insulin secretion and Type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Vilsbøll, T; Holst, Jens Juul

    2004-01-01

    the effect of GIP is severely impaired. The impaired GIP effect seems to have a genetic background, but could be aggravated by the diabetic state. The preserved effect of GLP-1 has inspired attempts to treat Type 2 diabetes with GLP-1 or analogues thereof, and intravenous GLP-1 administration has been shown...... the genes encoding their receptors have been deleted. In patients with Type 2 diabetes, the incretin effect is either greatly impaired or absent, and it is assumed that this could contribute to the inability of these patients to adjust their insulin secretion to their needs. In studies of the mechanism...... of the impaired incretin effect in Type 2 diabetic patients, it has been found that the secretion of GIP is generally normal, whereas the secretion of GLP-1 is reduced, presumably as a consequence of the diabetic state. It might be of even greater importance that the effect of GLP-1 is preserved whereas...

  9. The Role of Taste in Cephalic Phase of Insulin Secretion

    Directory of Open Access Journals (Sweden)

    M. Dušková

    2013-01-01

    Full Text Available The effect of a short gustatory signal of a sweet solution was tested on 15 young male volunteers. The experiment consisted of mouth rinsing with either a sucrose or aspartate solution or pure water as a placebo. Blood was then taken in short intervals of 0, 5, 10, 15 and 20 min. Blood glucose, C-peptide, insulin and cortisol were determined. While C-peptide and glucose were unaffected, a short-term increase in insulin was observed after the sucrose, but not after the aspartate or placebo. The increase in insulin was significant, though it amounted to only 0.5 mIU/l and lasted approx. 15 min reaching then the starting value. The decline of cortisol level within 20 min of the experiment was approx. 40 nmol/l, although it was also observed after aspartate or placebo mouth rinsing and was probably caused by stress factors or anticipation. In conclusion, the contribution of taste to the cephalic phase of insulin secretion is small yet significant, and mouth rinsing with 5% sucrose causes an insulin increase of just under 1 IU/l, which returns to starting level within 15 min.

  10. Insulin secretion and glucose uptake by isolated islets of the hamster. Effect of insulin, proinsulin and C-peptide

    Energy Technology Data Exchange (ETDEWEB)

    Dunbar, J C; McLaughlin, W J; Walsh, M F.J.; Foa, P P [Sinai Hospital of Detroit, Mich. (USA). Dept. of Research

    1976-01-01

    Isolated pancreatic islets of normal hamsters were perfused either in a closed or in a open system. When the buffer was recirculated and the endogenous insulin was allowed to accumulate, the islets secreted significantly less insulin than when the system was open and the endogenous insulin was washed away. The addition of monocomponent insulin or of proinsulin to the perfusion buffer significantly decreased insulin secretion. The inhibitory action of proinsulin was significantly greater than that of monocomponent insulin. C peptide had no effect. When pancreatic islets were incubated in a fixed volume of stationary buffer containing unlabeled glucose (1.0 mg or 3.0 mg/ml) and glucose-U-/sup 14/C (1.0 ..mu..C/ml), the amount of insulin secreted and the /sup 14/CO/sub 2/ produced by each islet decreased progressively as the number of islets in the sample increased. Under these conditions, the concentration of insulin required to inhibit insulin secretion increased with the concentration of glucose in the medium. Proinsulin did not alter the incorporation of leucine-4.5-/sup 3/H into total extractable insulin (insulin + proinsulin). Thus, insulin and proinsulin appear to inhibit insulin release, but not insulin synthesis.

  11. Impaired insulin secretion and glucose intolerance in synaptotagmin-7 null mutant mice

    DEFF Research Database (Denmark)

    Gustavsson, Natalia; Lao, Ye; Maximov, Anton

    2008-01-01

    and insulin release. Here, we show that synaptotagmin-7 is required for the maintenance of systemic glucose tolerance and glucose-stimulated insulin secretion. Mutant mice have normal insulin sensitivity, insulin production, islet architecture and ultrastructural organization, and metabolic and calcium...... secretion in pancreatic beta-cells. Of these other synaptotagmins, synaptotagmin-7 is one of the most abundant and is present in pancreatic beta-cells. To determine whether synaptotagmin-7 regulates Ca(2+)-dependent insulin secretion, we analyzed synaptotagmin-7 null mutant mice for glucose tolerance...... responses but exhibit impaired glucose-induced insulin secretion, indicating a calcium-sensing defect during insulin-containing secretory granule exocytosis. Taken together, our findings show that synaptotagmin-7 functions as a positive regulator of insulin secretion and may serve as a calcium sensor...

  12. 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....

  13. Midkine, a potential link between obesity and insulin resistance.

    Directory of Open Access Journals (Sweden)

    Nengguang Fan

    Full Text Available Obesity is associated with increased production of inflammatory mediators in adipose tissue, which contributes to chronic inflammation and insulin resistance. Midkine (MK is a heparin-binding growth factor with potent proinflammatory activities. We aimed to test whether MK is associated with obesity and has a role in insulin resistance. It was found that MK was expressed in adipocytes and regulated by inflammatory modulators (TNF-α and rosiglitazone. In addition, a significant increase in MK levels was observed in adipose tissue of obese ob/ob mice as well as in serum of overweight/obese subjects when compared with their respective controls. In vitro studies further revealed that MK impaired insulin signaling in 3T3-L1 adipocytes, as indicated by reduced phosphorylation of Akt and IRS-1 and decreased translocation of glucose transporter 4 (GLUT4 to the plasma membrane in response to insulin stimulation. Moreover, MK activated the STAT3-suppressor of cytokine signaling 3 (SOCS3 pathway in adipocytes. Thus, MK is a novel adipocyte-secreted factor associated with obesity and inhibition of insulin signaling in adipocytes. It may provide a potential link between obesity and insulin resistance.

  14. A common variation of the PTEN gene is associated with peripheral insulin resistance

    DEFF Research Database (Denmark)

    Grinder-Hansen, L; Ribel-Madsen, R; Wojtaszewski, Jørgen

    2016-01-01

    . RESULTS: The minor G allele of PTEN rs11202614 was associated with elevated fasting plasma insulin levels and a decreased peripheral glucose disposal rate, but not with the hepatic insulin resistance index or insulin secretion measured as the first-phase insulin response and disposition index. The single...... nucleotide polymorphism was not associated with either PI3K or Akt activities. CONCLUSION: A common PTEN variation is associated with peripheral insulin resistance and subsequent risk of developing T2D. However, the association with insulin resistance is not explained by decreased proximal insulin signalling......AIM: Phosphatase and tensin homologue (PTEN) reduces insulin sensitivity by inhibiting the phosphatidylinositol 3-kinase (PI3K)/v-akt murine thymoma viral oncogene homologue (Akt) pathway. This study investigated how a common single nucleotide polymorphism near PTEN, previously associated...

  15. Insulin resistance in porphyria cutanea tarda.

    Science.gov (United States)

    Calcinaro, F; Basta, G; Lisi, P; Cruciani, C; Pietropaolo, M; Santeusanio, F; Falorni, A; Calafiore, R

    1989-06-01

    It has been reported that patients with porphyria cutanea tarda (PCT) develop carbohydrate (CHO) intolerance and manifest diabetes melitus (DM) more frequently than the normal population. In order to verify whether this is due to insulin resistance we studied 5 patients with PCT and 5 normal subjects matched for age, sex and weight. In all the patients an evaluation consisted of the glycemic curve and insulin response to an iv glucose tolerance test (IVGTT: 0.33 g/kg) as well as of an evaluation of the circulating monocyte insulin receptors. Blood samples were drawn in the basal state to measure plasma levels of NEFA, glycerol, and intermediate metabolites. The patients with PCT showed normal glucose tolerance which was obtained, however, at the expense of the elevated insulin levels: therefore a condition of insulin resistance was demonstrated in these subjects. An involvement of the lipid metabolism, observed by the raised levels of plasma NEFA and glycerol, was also evident. The insulin binding to circulating monocytes was reduced but not enough to justify the degree of insulin resistance observed. Therefore, it could be hypothesized, in agreement with similar studies, that a postreceptor defect is responsible for the insulin-resistance observed in patients with PCT and that the reduction of insulin receptors is determined by the down regulation in response to elevated insulinemic levels. An alteration of the porphyrin metabolism might be responsible for this disorder.

  16. Selective insulin resistance in hepatocyte senescence

    International Nuclear Information System (INIS)

    Aravinthan, Aloysious; Challis, Benjamin; Shannon, Nicholas; Hoare, Matthew; Heaney, Judith; Alexander, Graeme J.M.

    2015-01-01

    Insulin resistance has been described in association with chronic liver disease for decades. Hepatocyte senescence has been demonstrated in chronic liver disease and as many as 80% of hepatocytes show a senescent phenotype in advanced liver disease. The aim of this study was to understand the role of hepatocyte senescence in the development of insulin resistance. Senescence was induced in HepG2 cells via oxidative stress. The insulin metabolic pathway was studied in control and senescent cells following insulin stimulation. GLUT2 and GLUT4 expressions were studied in HepG2 cells and human liver tissue. Further, GLUT2 and GLUT4 expressions were studied in three independent chronic liver disease cohorts. Signalling impairment distal to Akt in phosphorylation of AS160 and FoxO1 was evident in senescent HepG2 cells. Persistent nuclear localisation of FoxO1 was demonstrated in senescent cells despite insulin stimulation. Increased GLUT4 and decreased GLUT2 expressions were evident in senescent cells, human cirrhotic liver tissue and publically available liver disease datasets. Changes in GLUT expressions were associated with a poor clinical prognosis. In conclusion, selective insulin resistance is evident in senescent HepG2 cells and changes in GLUT expressions can be used as surrogate markers of hepatocyte senescence. - Highlights: • Senescent hepatocytes demonstrate selective insulin resistance. • GLUT changes act as markers of hepatocyte senescence and have prognostic value. • Study offers insight into long noticed intimacy of cirrhosis and insulin resistance

  17. Selective insulin resistance in hepatocyte senescence

    Energy Technology Data Exchange (ETDEWEB)

    Aravinthan, Aloysious [Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Cambridge (United Kingdom); Challis, Benjamin [Institute of Metabolic Sciences, University of Cambridge, Cambridge (United Kingdom); Shannon, Nicholas [Cancer Research UK Cambridge Institute, Cambridge (United Kingdom); Hoare, Matthew [Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Cambridge (United Kingdom); Cancer Research UK Cambridge Institute, Cambridge (United Kingdom); Heaney, Judith [Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Cambridge (United Kingdom); Foundation for Liver Research, Institute of Hepatology, London (United Kingdom); Alexander, Graeme J.M., E-mail: gja1000@doctors.org.uk [Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Cambridge (United Kingdom)

    2015-02-01

    Insulin resistance has been described in association with chronic liver disease for decades. Hepatocyte senescence has been demonstrated in chronic liver disease and as many as 80% of hepatocytes show a senescent phenotype in advanced liver disease. The aim of this study was to understand the role of hepatocyte senescence in the development of insulin resistance. Senescence was induced in HepG2 cells via oxidative stress. The insulin metabolic pathway was studied in control and senescent cells following insulin stimulation. GLUT2 and GLUT4 expressions were studied in HepG2 cells and human liver tissue. Further, GLUT2 and GLUT4 expressions were studied in three independent chronic liver disease cohorts. Signalling impairment distal to Akt in phosphorylation of AS160 and FoxO1 was evident in senescent HepG2 cells. Persistent nuclear localisation of FoxO1 was demonstrated in senescent cells despite insulin stimulation. Increased GLUT4 and decreased GLUT2 expressions were evident in senescent cells, human cirrhotic liver tissue and publically available liver disease datasets. Changes in GLUT expressions were associated with a poor clinical prognosis. In conclusion, selective insulin resistance is evident in senescent HepG2 cells and changes in GLUT expressions can be used as surrogate markers of hepatocyte senescence. - Highlights: • Senescent hepatocytes demonstrate selective insulin resistance. • GLUT changes act as markers of hepatocyte senescence and have prognostic value. • Study offers insight into long noticed intimacy of cirrhosis and insulin resistance.

  18. Calcineurin inhibitors acutely improve insulin sensitivity without affecting insulin secretion in healthy human volunteers

    DEFF Research Database (Denmark)

    Øzbay, Aygen; Møller, Niels; Juhl, Claus

    2012-01-01

    and tacrolimus has been attributed to both beta cell dysfunction and impaired insulin sensitivity. WHAT THIS STUDY ADDS: This is the first trial to investigate beta cell function and insulin sensitivity using gold standard methodology in healthy human volunteers treated with clinically relevant doses...... of ciclosporin and tacrolimus. We document that both drugs acutely increase insulin sensitivity, while first phase and pulsatile insulin secretion remain unaffected. This study demonstrates that ciclosporin and tacrolimus have similar acute effects on glucose metabolism in healthy humans. AIM The introduction...... of calcineurin inhibitors (CNIs) ciclosporin (CsA) and tacrolimus (Tac) has improved the outcome of organ transplants, but complications such as new onset diabetes mellitus after transplantation (NODAT) cause impairment of survival rates. The relative contribution of each CNI to the pathogenesis and development...

  19. LPS-Enhanced Glucose-Stimulated Insulin Secretion Is Normalized by Resveratrol

    DEFF Research Database (Denmark)

    Nøhr, Mark K; Dudele, Anete; Poulsen, Morten M

    2016-01-01

    we test the effect of LPS and the anti-inflammatory compound resveratrol on glucose homeostasis, insulin levels and inflammation. Mice were subcutaneously implanted with osmotic mini pumps infusing either low-dose LPS or saline for 28 days. Half of the mice were treated with resveratrol delivered...... through the diet. LPS caused increased inflammation of the liver and adipose tissue (epididymal and subcutaneous) together with enlarged spleens and increased number of leukocytes in the blood. Resveratrol specifically reduced the inflammatory status in epididymal fat (reduced expression of TNFa and Il1b......, whereas the increased macrophage infiltration was unaltered) without affecting the other tissues investigated. By LC-MS, we were able to quantitate resveratrol metabolites in epididymal but not subcutaneous adipose tissue. LPS induced insulin resistance as the glucose-stimulated insulin secretion during...

  20. The origins and drivers of insulin resistance.

    Science.gov (United States)

    Johnson, Andrew M F; Olefsky, Jerrold M

    2013-02-14

    Obesity-induced insulin resistance is the major determinant of metabolic syndrome, which precedes the development of type 2 diabetes mellitus and is thus the driving force behind the emerging diabetes epidemic. The precise causes of insulin resistance are varied, and the relative importance of each is a matter of ongoing research. Here, we offer a Perspective on the heterogeneous etiology of insulin resistance, focusing in particular on the role of inflammation, lipid metabolism, and the gastrointestinal microbiota. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. Dietary Sodium Restriction Decreases Insulin Secretion Without Affecting Insulin Sensitivity in Humans

    Science.gov (United States)

    Byrne, Loretta M.; Yu, Chang; Wang, Thomas J.; Brown, Nancy J.

    2014-01-01

    Context: Interruption of the renin-angiotensin-aldosterone system prevents incident diabetes in high-risk individuals, although the mechanism remains unclear. Objective: To test the hypothesis that activation of the endogenous renin-angiotensin-aldosterone system or exogenous aldosterone impairs insulin secretion in humans. Design: We conducted a randomized, blinded crossover study of aldosterone vs vehicle and compared the effects of a low-sodium versus a high-sodium diet. Setting: Academic clinical research center. Participants: Healthy, nondiabetic, normotensive volunteers. Interventions: Infusion of exogenous aldosterone (0.7 μg/kg/h for 12.5 h) or vehicle during low or high sodium intake. Low sodium (20 mmol/d; n = 12) vs high sodium (160 mmol/d; n = 17) intake for 5–7 days. Main Outcome Measures: Change in acute insulin secretory response assessed during hyperglycemic clamps while in sodium balance during a low-sodium vs high-sodium diet during aldosterone vs vehicle. Results: A low-sodium diet increased endogenous aldosterone and plasma renin activity, and acute glucose-stimulated insulin (−16.0 ± 5.6%; P = .007) and C-peptide responses (−21.8 ± 8.4%; P = .014) were decreased, whereas the insulin sensitivity index was unchanged (−1.0 ± 10.7%; P = .98). Aldosterone infusion did not affect the acute insulin response (+1.8 ± 4.8%; P = .72) or insulin sensitivity index (+2.0 ± 8.8%; P = .78). Systolic blood pressure and serum potassium were similar during low and high sodium intake and during aldosterone infusion. Conclusions: Low dietary sodium intake reduces insulin secretion in humans, independent of insulin sensitivity. PMID:25029426

  2. Insulin resistance and improvements in signal transduction.

    Science.gov (United States)

    Musi, Nicolas; Goodyear, Laurie J

    2006-02-01

    Type 2 diabetes and obesity are common metabolic disorders characterized by resistance to the actions of insulin to stimulate skeletal muscle glucose disposal. Insulin-resistant muscle has defects at several steps of the insulin-signaling pathway, including decreases in insulin-stimulated insulin receptor and insulin receptor substrate-1 tyrosine phosphorylation, and phosphatidylinositol 3-kinase (PI 3-kinase) activation. One approach to increase muscle glucose disposal is to reverse/improve these insulin-signaling defects. Weight loss and thiazolidinediones (TZDs) improve glucose disposal, in part, by increasing insulin-stimulated insulin receptor and IRS-1 tyrosine phosphorylation and PI 3-kinase activity. In contrast, physical training and metformin improve whole-body glucose disposal but have minimal effects on proximal insulin-signaling steps. A novel approach to reverse insulin resistance involves inhibition of the stress-activated protein kinase Jun N-terminal kinase (JNK) and the protein tyrosine phosphatases (PTPs). A different strategy to increase muscle glucose disposal is by stimulating insulin-independent glucose transport. AMP-activated protein kinase (AMPK) is an enzyme that works as a fuel gauge and becomes activated in situations of energy consumption, such as muscle contraction. Several studies have shown that pharmacologic activation of AMPK increases glucose transport in muscle, independent of the actions of insulin. AMPK activation is also involved in the mechanism of action of metformin and adiponectin. Moreover, in the hypothalamus, AMPK regulates appetite and body weight. The effect of AMPK to stimulate muscle glucose disposal and to control appetite makes it an important pharmacologic target for the treatment of type 2 diabetes and obesity.

  3. Insulin resistance and maximal oxygen uptake

    DEFF Research Database (Denmark)

    Seibaek, Marie; Vestergaard, Henrik; Burchardt, Hans

    2003-01-01

    BACKGROUND: Type 2 diabetes, coronary atherosclerosis, and physical fitness all correlate with insulin resistance, but the relative importance of each component is unknown. HYPOTHESIS: This study was undertaken to determine the relationship between insulin resistance, maximal oxygen uptake......, and the presence of either diabetes or ischemic heart disease. METHODS: The study population comprised 33 patients with and without diabetes and ischemic heart disease. Insulin resistance was measured by a hyperinsulinemic euglycemic clamp; maximal oxygen uptake was measured during a bicycle exercise test. RESULTS......: There was a strong correlation between maximal oxygen uptake and insulin-stimulated glucose uptake (r = 0.7, p = 0.001), and maximal oxygen uptake was the only factor of importance for determining insulin sensitivity in a model, which also included the presence of diabetes and ischemic heart disease. CONCLUSION...

  4. Insulin sensitivity and insulin secretion at birth in intrauterine growth retarded infants.

    Science.gov (United States)

    Setia, Sajita; Sridhar, M G; Bhat, Vishnu; Chaturvedula, Lata; Vinayagamoorti, R; John, Mathew

    2006-06-01

    To study insulin sensitivity, secretion and relation of insulin levels with birth weight and ponderal index in intrauterine growth retarded (IUGR) infants at birth. We studied 30 IUGR and 30 healthy newborns born at term by vaginal delivery in Jipmer, Pondicherry, India. Cord blood was collected at the time of delivery for measurement of plasma glucose and insulin. When compared with healthy newborns, IUGR newborns had lower plasma glucose levels (mean 2.3+/-0.98 versus 4.1+/-0.51 mmol/L, p<0.001); lower plasma insulin levels (mean 4.5+/-2.64 versus 11.03+/-1.68 microU/L, p<0.001); higher insulin sensitivity calculated using G/I ratio (mean 11.6+/-5.1 versus 6.7+/-0.31, p<0.001), HOMA IS (mean 5.5+/-6.0 versus 0.53+/-0.15, p<0.001), and QUICKI (mean 0.47+/-0.12 versus 0.34+/-0.02, p<0.001); and decreased pancreatic beta-cell function test measured as I/G (mean 0.10+/-0.037 versus 0.15+/-0.006, p<0.001). A positive correlation was identified between insulin levels and birth weight in both the healthy control group (r2 = 0.17, p = 0.024) and IUGR group (r2 = 0.13, p = 0.048). However correlation of insulin levels with ponderal index was much more confident in both healthy control (r2 = 0.90, p<0.001) and IUGR groups (r2 = 0.28, p = 0.003). Insulin status correlated both with birth weight and ponderal index more confidently in control group than in IUGR group. At birth, IUGR infants are hypoglycaemic, hypoinsulinaemic and display increased insulin sensitivity and decreased pancreatic beta-cell function. Insulin levels correlate with ponderal index much more confidently than with birth weight.

  5. Mitochondrial GTP Regulates Glucose-Induced Insulin Secretion

    OpenAIRE

    Kibbey, Richard G.; Pongratz, Rebecca L.; Romanelli, Anthony J.; Wollheim, Claes B.; Cline, Gary W.; Shulman, Gerald I.

    2007-01-01

    Substrate-level mitochondrial GTP (mtGTP) and ATP (mtATP) synthesis occurs by nucleotide-specific isoforms of the tricarboxylic acid (TCA) cycle enzyme succinyl CoA synthetase (SCS). Unlike mtATP, each molecule of glucose metabolized produces approximately one mtGTP in pancreatic β-cells independent of coupling with oxidative phosphorylation making mtGTP a potentially important fuel signal. siRNA suppression of the GTP-producing pathway (ΔSCS-GTP) reduced glucose-stimulated insulin secretion ...

  6. Variants within the calpain-10 gene on chromosome 2q37 (NIDDM1) and relationships to type 2 diabetes, insulin resistance, and impaired acute insulin secretion among Scandinavian Caucasians

    DEFF Research Database (Denmark)

    Rasmussen, Søren K; Urhammer, Søren A; Berglund, Lars Erik

    2002-01-01

    subjects compared with 200 glucose-tolerant control subjects (0.06 vs. 0.05; odds ratio 1.32 [95% CI 0.58-3.30]). In glucose-tolerant subjects, neither the single-nucleotide polymorphisms individually nor the 112/121 combination were associated with alterations in plasma glucose, serum insulin, or serum C...

  7. Role of mitochondrial function in insulin resistance

    NARCIS (Netherlands)

    Brands, Myrte; Verhoeven, Arthur J.; Serlie, Mireille J.

    2012-01-01

    The obesity pandemic increases the prevalence of type 2 diabetes (DM2).DM2 develops when pancreatic β-cells fail and cannot compensate for the decrease in insulin sensitivity. How excessive caloric intake and weight gain cause insulin resistance has not completely been elucidated.Skeletal muscle is

  8. Patients with psoriasis are insulin resistant

    DEFF Research Database (Denmark)

    Gyldenløve, Mette; Storgaard, Heidi; Holst, Jens Juul

    2015-01-01

    BACKGROUND: Patients with psoriasis have increased risk of type 2 diabetes. The pathophysiology is largely unknown, but it is hypothesized that systemic inflammation causes insulin resistance. Insulin sensitivity has only been sparsely investigated in patients with psoriasis, and previous studies...... with healthy control subjects. This supports that psoriasis may be a prediabetic condition....

  9. A novel surrogate index for hepatic insulin resistance.

    LENUS (Irish Health Repository)

    Vangipurapu, J

    2011-03-01

    In epidemiological and genetic studies surrogate indices are needed to investigate insulin resistance in different insulin-sensitive tissues. Our objective was to develop a surrogate index for hepatic insulin resistance.

  10. Heterogeneity and compartmental properties of insulin storage and secretion in rat islets

    International Nuclear Information System (INIS)

    Gold, G.; Landahl, H.D.; Gishizky, M.L.; Grodsky, G.M.

    1982-01-01

    To investigate compartmental properties of insulin storage and secretion, isolated rat islets were used for pulse-labeling experiments, after which proinsulin and insulin were purified rigorously. Processing of proinsulin to insulin neared completion by 3 h without additional loss of either radioactive peptide by cellular or extracellular proteolysis. The amount of labeled hormone rapidly diminished in islets; it was secreted at a higher fractional rate than immunoreactive insulin, resulting in secreted insulin's having a higher specific activity than the average cellular insulin. Newly synthesized insulin, therefore, was secreted preferentially. Changes in the specific activity of secreted and cellular insulin with time were consistent with changes predicted for islets containing 33% of their total insulin in a glucose-labile compartment. Predictions were based on steady-state analysis of a simple storage-limited representation of B cell function. Islets from either the dorsal or ventral part of the pancreas also contained 33% of their total insulin in a glucose-labile compartment. The same compartment was mobilized by 20 mM glucose, 50 mM potassium + 2 mM glucose, or 20 MM glucose + 1 mM 3-isobutylmethylxanthine as indicated by the specific activity ratio of secreted vs. cellular insulin, even though average secretion rates with these stimuli differed by more than threefold. In the absence of calcium, the effectiveness of 20 mM glucose as a secretagogue declined markedly, and the older stored insulin was preferentially mobilized because secreted insulin had a lower rather than a higher specific activity than cellular insulin. Results provide insight into the mechanisms of nonrandom mobilization and secretion of insulin form the B cell

  11. FoxO1 Plays an Important Role in Regulating ?-Cell Compensation for Insulin Resistance in Male Mice

    OpenAIRE

    Zhang, Ting; Kim, Dae Hyun; Xiao, Xiangwei; Lee, Sojin; Gong, Zhenwei; Muzumdar, Radhika; Calabuig-Navarro, Virtu; Yamauchi, Jun; Harashima, Hideyoshi; Wang, Rennian; Bottino, Rita; Alvarez-Perez, Juan Carlos; Garcia-Oca?a, Adolfo; Gittes, George; Dong, H. Henry

    2016-01-01

    ?-Cell compensation is an essential mechanism by which ?-cells increase insulin secretion for overcoming insulin resistance to maintain euglycemia in obesity. Failure of ?-cells to compensate for insulin resistance contributes to insulin insufficiency and overt diabetes. To understand the mechanism of ?-cell compensation, we characterized the role of forkhead box O1 (FoxO1) in ?-cell compensation in mice under physiological and pathological conditions. FoxO1 is a key transcription factor that...

  12. Insulin resistance in Nigerians with essential hypertension

    African Journals Online (AJOL)

    EB

    2013-09-03

    Sep 3, 2013 ... Keywords: Hypertension, Insulin resistance, Homeostasis model assessment ... worldwide and its prevalence is predicted to increase by 60% by 2025, when a ... model is derived from a mathematical assessment .... Drug type.

  13. Coffee Consumption Attenuates Insulin Resistance and Glucose ...

    African Journals Online (AJOL)

    olayemitoyin

    Alzheimer's disease (CBS 2012), dementia (Health news 2012) and ... the effects of coffee on insulin resistance and glucose tolerance as ..... mortality among patients with type 2 diabetes. ... transporter family: Structure, function and tissue-.

  14. Insulin resistance in obese children and adolescents

    Directory of Open Access Journals (Sweden)

    Monica Cristina dos Santos Romualdo

    2014-11-01

    Conclusion: The results confirmed that insulin resistance is present in many obese children and adolescents, and that this condition is associated with alterations that represent an increased risk for developing metabolic disorders in adulthood.

  15. Impaired crosstalk between pulsatile insulin and glucagon secretion in prediabetic individuals

    DEFF Research Database (Denmark)

    Rohrer, Stefan; Menge, Björn A; Grüber, Lena

    2012-01-01

    Postprandial hyperglucagonemia is frequently found in patients with diabetes. Recently, a loss of the inverse relationship between pulsatile insulin and glucagon secretion has been reported in patients with type 2 diabetes. The crosstalk between pulsatile islet hormone secretion in prediabetic...

  16. IRS-1 serine phosphorylation and insulin resistance in skeletal muscle from pancreas tranplant recipient

    DEFF Research Database (Denmark)

    Bouzakri, K; Karlsson, HRK; Vestergaard, Henrik

    2006-01-01

    Insulin-dependent diabetic recipients of successful pancreas allografts achieve self-regulatory insulin secretion and discontinue exogenous insulin therapy; however, chronic hyperinsulinemia and impaired insulin sensitivity generally develop. To determine whether insulin resistance is accompanied....... In conclusion, peripheral insulin resistance in pancreas-kidney transplant recipients may arise from a negative feedback regulation of the canonical insulin-signaling cascade from excessive serine phosphorylation of IRS-1, possibly as a consequence of immunosuppressive therapy and hyperinsulinemia....... insulin receptor substrate (IRS)-1 Ser (312) and Ser (616) phosphorylation, IRS-1-associated phosphatidylinositol 3-kinase activity, and extracellular signal-regulated kinase (ERK)-1/2 phosphorylation were elevated in pancreas-kidney transplant recipients, coincident with fasting hyperinsulinemia. Basal...

  17. Increased CD19+CD24+CD27+ B regulatory cells are associated with insulin resistance in patients with type I Hashimoto's thyroiditis.

    Science.gov (United States)

    Yang, Min; Du, Changji; Wang, Yinping; Liu, Jun

    2017-06-01

    Hashimoto's thyroiditis (HT) is characterized by dysregulated immune responses and is commonly associated with insulin resistance. However, the mechanism of insulin resistance in HT remains to be fully elucidated. The aim of the present study was to investigate the correlation between the percentage of B regulatory lymphocytes (Bregs) and insulin resistance in patients with HT but with normal thyroid function (type I). A total of 59 patients with type I HT and 38 healthy volunteers were enrolled in the study. An oral glucose tolerance test was performed to measure insulin secretion and assess β‑cell functions. Flow cytometry was performed to examine the percentages of lymphocyte populations. The patients with HT exhibited normal fasting and postprandial glucose and fasting insulin secretion, but increased secretion of early‑phase and total insulin. The patients with HT also had insufficient β‑cell compensation for insulin resistance, indicated by a reduced disposition index, in the fasting state. An elevation in the percentage of CD19+CD24+CD27+ Bregs was also observed, which correlated positively with insulin secretion and insulin resistance in the fasting state. The patients with type I HT had postprandial insulin resistance and insufficient β‑cell compensation for fasting insulin resistance. Therefore, the increase in CD19+CD24+CD27+ Bregs was closely associated with fasting insulin secretion. These results provide novel insight into the mechanism of insulin resistance in HT.

  18. Metabolic Profiles in Obese Children and Adolescents with Insulin Resistance

    Directory of Open Access Journals (Sweden)

    Marko Kostovski

    2018-03-01

    CONCLUSION: Higher percentage of insulin-resistant participants was of female gender and was adolescents. In general, insulin resistant obese children and adolescents tend to have a worse metabolic profile in comparison to individuals without insulin resistance. It is of note that the highest insulin resistance was also linked with the highest concentrations of triglycerides.

  19. Does epigenetic dysregulation of pancreatic islets contribute to impaired insulin secretion and type 2 diabetes?

    Science.gov (United States)

    Dayeh, Tasnim; Ling, Charlotte

    2015-10-01

    β cell dysfunction is central to the development and progression of type 2 diabetes (T2D). T2D develops when β cells are not able to compensate for the increasing demand for insulin caused by insulin resistance. Epigenetic modifications play an important role in establishing and maintaining β cell identity and function in physiological conditions. On the other hand, epigenetic dysregulation can cause a loss of β cell identity, which is characterized by reduced expression of genes that are important for β cell function, ectopic expression of genes that are not supposed to be expressed in β cells, and loss of genetic imprinting. Consequently, this may lead to β cell dysfunction and impaired insulin secretion. Risk factors that can cause epigenetic dysregulation include parental obesity, an adverse intrauterine environment, hyperglycemia, lipotoxicity, aging, physical inactivity, and mitochondrial dysfunction. These risk factors can affect the epigenome at different time points throughout the lifetime of an individual and even before an individual is conceived. The plasticity of the epigenome enables it to change in response to environmental factors such as diet and exercise, and also makes the epigenome a good target for epigenetic drugs that may be used to enhance insulin secretion and potentially treat diabetes.

  20. Design and clinical pilot testing of the model-based dynamic insulin sensitivity and secretion test (DISST).

    Science.gov (United States)

    Lotz, Thomas F; Chase, J Geoffrey; McAuley, Kirsten A; Shaw, Geoffrey M; Docherty, Paul D; Berkeley, Juliet E; Williams, Sheila M; Hann, Christopher E; Mann, Jim I

    2010-11-01

    Insulin resistance is a significant risk factor in the pathogenesis of type 2 diabetes. This article presents pilot study results of the dynamic insulin sensitivity and secretion test (DISST), a high-resolution, low-intensity test to diagnose insulin sensitivity (IS) and characterize pancreatic insulin secretion in response to a (small) glucose challenge. This pilot study examines the effect of glucose and insulin dose on the DISST, and tests its repeatability. DISST tests were performed on 16 subjects randomly allocated to low (5 g glucose, 0.5 U insulin), medium (10 g glucose, 1 U insulin) and high dose (20 g glucose, 2 U insulin) protocols. Two or three tests were performed on each subject a few days apart. Average variability in IS between low and medium dose was 10.3% (p=.50) and between medium and high dose 6.0% (p=.87). Geometric mean variability between tests was 6.0% (multiplicative standard deviation (MSD) 4.9%). Geometric mean variability in first phase endogenous insulin response was 6.8% (MSD 2.2%). Results were most consistent in subjects with low IS. These findings suggest that DISST may be an easily performed dynamic test to quantify IS with high resolution, especially among those with reduced IS. © 2010 Diabetes Technology Society.

  1. Loss of inverse relationship between pulsatile insulin and glucagon secretion in patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Menge, Björn A; Grüber, Lena; Jørgensen, Signe M

    2011-01-01

    In patients with type 2 diabetes, glucagon levels are often increased. Furthermore, pulsatile secretion of insulin is disturbed in such patients. Whether pulsatile glucagon secretion is altered in type 2 diabetes is not known.......In patients with type 2 diabetes, glucagon levels are often increased. Furthermore, pulsatile secretion of insulin is disturbed in such patients. Whether pulsatile glucagon secretion is altered in type 2 diabetes is not known....

  2. Circulating interleukin-6 in relation to adiposity, insulin action, and insulin secretion

    DEFF Research Database (Denmark)

    Vozarova, B; Weyer, C; Hanson, K

    2001-01-01

    Plasma concentrations of interleukin-6 (IL-6), a proinflammatory cytokine produced and released in part by adipose tissue, are elevated in people with obesity and type 2 diabetes. Because recent studies suggest that markers of inflammation predict the development of type 2 diabetes, we examined w...... whether circulating plasma IL-6 concentrations were related to direct measures of insulin resistance and insulin secretory dysfunction in Pima Indians, a population with high rates of obesity and type 2 diabetes....

  3. Closing in on the Mechanisms of Pulsatile Insulin Secretion.

    Science.gov (United States)

    Bertram, Richard; Satin, Leslie S; Sherman, Arthur S

    2018-03-01

    Insulin secretion from pancreatic islet β-cells occurs in a pulsatile fashion, with a typical period of ∼5 min. The basis of this pulsatility in mouse islets has been investigated for more than four decades, and the various theories have been described as either qualitative or mathematical models. In many cases the models differ in their mechanisms for rhythmogenesis, as well as other less important details. In this Perspective, we describe two main classes of models: those in which oscillations in the intracellular Ca 2+ concentration drive oscillations in metabolism, and those in which intrinsic metabolic oscillations drive oscillations in Ca 2+ concentration and electrical activity. We then discuss nine canonical experimental findings that provide key insights into the mechanism of islet oscillations and list the models that can account for each finding. Finally, we describe a new model that integrates features from multiple earlier models and is thus called the Integrated Oscillator Model. In this model, intracellular Ca 2+ acts on the glycolytic pathway in the generation of oscillations, and it is thus a hybrid of the two main classes of models. It alone among models proposed to date can explain all nine key experimental findings, and it serves as a good starting point for future studies of pulsatile insulin secretion from human islets. © 2018 by the American Diabetes Association.

  4. Mitochondrial GTP Regulates Glucose-Induced Insulin Secretion

    Science.gov (United States)

    Kibbey, Richard G.; Pongratz, Rebecca L.; Romanelli, Anthony J.; Wollheim, Claes B.; Cline, Gary W.; Shulman, Gerald I.

    2007-01-01

    Summary Substrate-level mitochondrial GTP (mtGTP) and ATP (mtATP) synthesis occurs by nucleotide-specific isoforms of the tricarboxylic acid (TCA) cycle enzyme succinyl CoA synthetase (SCS). Unlike mtATP, each molecule of glucose metabolized produces approximately one mtGTP in pancreatic β-cells independent of coupling with oxidative phosphorylation making mtGTP a potentially important fuel signal. siRNA suppression of the GTP-producing pathway (ΔSCS-GTP) reduced glucose-stimulated insulin secretion (GSIS) by 50%, whereas suppression of the parallel ATP-producing isoform (ΔSCS-ATP) increased GSIS by two-fold in INS-1 832/13 cells and cultured rat islets. Insulin secretion correlated with increases in cytosolic calcium but not with changes in NAD(P)H or the ATP/ADP ratio. These data suggest an important role for mtGTP in mediating GSIS in β-cells by modulation of mitochondrial metabolism possibly via influencing mitochondrial calcium. Furthermore, by virtue of its tight coupling to TCA oxidation rates, mtGTP production may serve as an important molecular signal of TCA cycle activity. PMID:17403370

  5. Central nervous insulin resistance: a promising target in the treatment of metabolic and cognitive disorders?

    Science.gov (United States)

    Hallschmid, M; Schultes, B

    2009-11-01

    Research on functions and signalling pathways of insulin has traditionally focused on peripheral tissues such as muscle, fat and liver, while the brain was commonly believed to be insensitive to the effects of this hormone secreted by pancreatic beta cells. However, since the discovery some 30 years ago that insulin receptors are ubiquitously found in the central nervous system, an ever-growing research effort has conclusively shown that circulating insulin accesses the brain, which itself does not synthesise insulin, and exerts pivotal functions in central nervous networks. As an adiposity signal reflecting the amount of body fat, insulin provides direct negative feedback to hypothalamic nuclei that control whole-body energy and glucose homeostasis. Moreover, insulin affects distinct cognitive processes, e.g. by triggering the formation of psychological memory contents. Accordingly, metabolic and cognitive disorders such as obesity, type 2 diabetes mellitus and Alzheimer's disease are associated with resistance of central nervous structures to the effects of insulin, which may derive from genetic polymorphisms as well as from long-term exposure to excess amounts of circulating insulin due to peripheral insulin resistance. Thus, overcoming central nervous insulin resistance, e.g. by pharmacological interventions, appears to be an attractive strategy in the treatment and prevention of these disorders. Enhancement of central nervous insulin signalling by administration of intranasal insulin, insulin analogues and insulin sensitisers in basic research approaches has yielded encouraging results that bode well for the successful translation of these effects into future clinical practice.

  6. [Primary study on characteristics of insulin secretion rate, metabolic clearance rate and sensitivity in non-insulin-dependent diabetic subjects from multiplex diabetic pedigrees].

    Science.gov (United States)

    Ran, J; Cheng, H; Li, F

    2000-01-01

    index (BMI) (P < 0.01), and MCR-I had significant negative correlation with AUCC (P < 0.01). There are obvious impaired first phase insulin secretion after glucose challenge in non-insulin-dependent diabetic subjects from MDP. Decrease in endogenous MCR-I might be an important factor to hyperinsulinemia and insulin resistance. Increased insulin secretion, decreased MCR-I and insulin sensitivity can be observed in abdominal obese subjects of control group.

  7. Insulin resistance: vascular function and exercise

    Directory of Open Access Journals (Sweden)

    Moon-Hyon Hwang

    2016-09-01

    Full Text Available Insulin resistance associated with metabolic syndrome and Type 2 diabetes mellitus is an epidemic metabolic disorder, which increases the risk of cardiovascular complications. Impaired vascular endothelial function is an early marker for atherosclerosis, which causes cardiovascular complications. Both experimental and clinical studies indicate that endothelial dysfunction in vasculatures occurs with insulin resistance. The associated physiological mechanisms are not fully appreciated yet, however, it seems that augmented oxidative stress, a physiological imbalance between oxidants and antioxidants, in vascular cells is a possible mechanism involved in various vascular beds with insulin resistance and hyperglycemia. Regardless of the inclusion of resistance exercise, aerobic exercise seems to be beneficial for vascular endothelial function in both large conduit and small resistance vessels in both clinical and experimental studies with insulin resistance. In clinical cases, aerobic exercise over 8 weeks with higher intensity seems more beneficial than the cases with shorter duration and lower intensity. However, more studies are needed in the future to elucidate the physiological mechanisms by which vascular endothelial function is impaired in insulin resistance and improved with aerobic exercise.

  8. Glucose-stimulated prehepatic insulin secretion is associated with circulating alanine, triglyceride, glucagons, lactate and TNF-alfa in patients with HIV-lipodystrophy

    DEFF Research Database (Denmark)

    Haugaard, Steen B; Andersen, Ove; Pedersen, SB

    2006-01-01

    with the remaining HIV-infected patients (all Ptriglyceride, alanine, glucagon, lactate and TNF-alpha may be associated with alterations in the first-phase prehepatic insulin secretion response to intravenous glucose in normoglycaemic lipodystrophic HIV-infected patients.......OBJECTIVES: We examined whether insulin-resistant lipodystrophic HIV-infected patients with known high fasting prehepatic insulin secretion rates (FISRs) displayed alterations in first-phase prehepatic insulin response to intravenous glucose (ISREG0-10 min). METHODS: Eighteen normoglycaemic...... lipodystrophic HIV-infected (LIPO) patients and 25 normoglycaemic nonlipodystrophic HIV-infected patients (controls) were included in the study. The prehepatic insulin secretion rate was estimated by deconvolution of C-peptide concentrations, and insulin sensitivity (SIRd) was estimated by the glucose clamp...

  9. Glucose-stimulated prehepatic insulin secretion is associated with circulating alanine, triglyceride, glucagon, lactate and TNF-alpha in patients with HIV-lipodystrophy

    DEFF Research Database (Denmark)

    Haugaard, S B; Andersen, O; Pedersen, S B

    2006-01-01

    with the remaining HIV-infected patients (all Ptriglyceride, alanine, glucagon, lactate and TNF-alpha may be associated with alterations in the first-phase prehepatic insulin secretion response to intravenous glucose in normoglycaemic lipodystrophic HIV-infected patients.......OBJECTIVES: We examined whether insulin-resistant lipodystrophic HIV-infected patients with known high fasting prehepatic insulin secretion rates (FISRs) displayed alterations in first-phase prehepatic insulin response to intravenous glucose (ISREG0-10 min). METHODS: Eighteen normoglycaemic...... lipodystrophic HIV-infected (LIPO) patients and 25 normoglycaemic nonlipodystrophic HIV-infected patients (controls) were included in the study. The prehepatic insulin secretion rate was estimated by deconvolution of C-peptide concentrations, and insulin sensitivity (SIRd) was estimated by the glucose clamp...

  10. Insulin resistance and serum parameters of iron status in type 2 diabetics

    International Nuclear Information System (INIS)

    Zafar, U.

    2011-01-01

    Background: Type 2 diabetes mellitus (T2DM) is a predominant public health concern worldwide, accounting for 90% of the cases of diabetes globally. Pathogenesis of T2DM involves insulin resistance, defective insulin secretion and increased glucose production by the liver. Subclinical haemochromatosis has been considered as one of the probable causes of insulin resistance and diabetes mellitus. The aim of this study was to determine and correlate insulin resistance and serum parameters of iron status (serum ferritin and transferrin saturation) in type 2 diabetics. Methods: It was a correlational study. This study was conducted on sixty male patients with type 2 diabetes mellitus. Fasting blood sample was taken from each subject and analysed for glucose, haemoglobin, insulin, iron, Total Iron Binding Capacity (TIBC) and ferritin. Insulin resistance was determined by HOMA-IR index. Transferrin saturation was calculated from serum iron and TIBC. Data was analysed using SPSS-17. Results: There was significant positive correlation between insulin resistance and transferrin saturation, but there was no significant correlation of insulin resistance with blood haemoglobin, serum iron and serum ferritin in type 2 diabetics. Conclusion: Correlation between insulin resistance and transferrin saturation reveals that iron has negative impact on insulin sensitivity in type 2 diabetics. (author)

  11. Effect of Artemisia dracunculus Administration on Glycemic Control, Insulin Sensitivity, and Insulin Secretion in Patients with Impaired Glucose Tolerance.

    Science.gov (United States)

    Méndez-Del Villar, Miriam; Puebla-Pérez, Ana M; Sánchez-Peña, María J; González-Ortiz, Luis J; Martínez-Abundis, Esperanza; González-Ortiz, Manuel

    2016-05-01

    To evaluate the effect of Artemisia dracunculus on glycemic control, insulin sensitivity, and insulin secretion in patients with impaired glucose tolerance (IGT). A randomized, double blind, placebo-controlled clinical trial was performed in 24 patients with diagnosis of IGT. Before and after the intervention, glucose and insulin levels were measured every 30 min for 2 h after a 75-g dextrose load, along with glycated hemoglobin A1c (A1C) and lipid profile. Twelve patients received A. dracunculus (1000 mg) before breakfast and dinner for 90 days; the remaining 12 patients received placebo. Area under the curve (AUC) of glucose and insulin, total insulin secretion, first phase of insulin secretion, and insulin sensitivity were calculated. Wilcoxon signed-rank, Mann-Whitney U, and chi-square tests were used for statistical analyses. The institutional ethics committee approved the protocol. After A. dracunculus administration, there were significant decreases in systolic blood pressure (SBP; 120.0 ± 11.3 vs. 113.0 ± 11.2 mmHg, P AUC of insulin (56,136.0 ± 27,426.0 vs. 44,472.0 ± 23,370.0 pmol/L, P AUC of insulin, and total insulin secretion with a significant increase in HDL-C levels.

  12. Estradiol Protects Proopiomelanocortin Neurons Against Insulin Resistance.

    Science.gov (United States)

    Qiu, Jian; Bosch, Martha A; Meza, Cecilia; Navarro, Uyen-Vy; Nestor, Casey C; Wagner, Edward J; Rønnekleiv, Oline K; Kelly, Martin J

    2018-02-01

    Insulin resistance is at the core of the metabolic syndrome, and men exhibit a higher incidence of metabolic syndrome than women in early adult life, but this sex advantage diminishes sharply when women reach the postmenopausal state. Because 17β-estradiol (E2) augments the excitability of the anorexigenic proopiomelanocortin (POMC) neurons, we investigated the neuroprotective effects of E2 against insulin resistance in POMC neurons from diet-induced obese (DIO) female and male mice. The efficacy of insulin to activate canonical transient receptor potential 5 (TRPC5) channels and depolarize POMC neurons was significantly reduced in DIO male mice but not in DIO female mice. However, the insulin response in POMC neurons was abrogated in ovariectomized DIO females but restored with E2 replacement. E2 increased T-type calcium channel Cav3.1 messenger RNA (mRNA) expression and whole-cell currents but downregulated stromal-interaction molecule 1 mRNA, which rendered POMC neurons more excitable and responsive to insulin-mediated TRPC5 channel activation. Moreover, E2 prevented the increase in suppressor of cytokine signaling-3 mRNA expression with DIO as seen in DIO males. As proof of principle, insulin [intracerebroventricular injection into the third ventricle (ICV)] decreased food intake and increased metabolism in female but not male guinea pigs fed a high-fat diet. The uncoupling of the insulin receptor from its downstream effector system was corroborated by the reduced expression of phosphorylated protein kinase B in the arcuate nucleus of male but not female guinea pigs following insulin. Therefore, E2 protects female POMC neurons from insulin resistance by enhancing POMC neuronal excitability and the coupling of insulin receptor to TRPC5 channel activation. Copyright © 2018 Endocrine Society.

  13. Metformin reduces insulin resistance and the tendency toward ...

    African Journals Online (AJOL)

    Ibrahim Eldaghayes

    2018-05-11

    May 11, 2018 ... insulin concentrations, in addition to urinary cortisol:creatinine ratio, Homeostatic Model Assessment (HOMA) for ... affecting the insulin synthesis and secretion of ... Likewise, no dog with increased Blood Urea Nitrogen.

  14. Novel Zn2+ Modulated GPR39 Receptor Agonists Do Not Drive Acute Insulin Secretion in Rodents.

    Directory of Open Access Journals (Sweden)

    Ola Fjellström

    Full Text Available Type 2 diabetes (T2D occurs when there is insufficient insulin release to control blood glucose, due to insulin resistance and impaired β-cell function. The GPR39 receptor is expressed in metabolic tissues including pancreatic β-cells and has been proposed as a T2D target. Specifically, GPR39 agonists might improve β-cell function leading to more adequate and sustained insulin release and glucose control. The present study aimed to test the hypothesis that GPR39 agonism would improve glucose stimulated insulin secretion in vivo. A high throughput screen, followed by a medicinal chemistry program, identified three novel potent Zn2+ modulated GPR39 agonists. These agonists were evaluated in acute rodent glucose tolerance tests. The results showed a lack of glucose lowering and insulinotropic effects not only in lean mice, but also in diet-induced obese (DIO mice and Zucker fatty rats. It is concluded that Zn2+ modulated GPR39 agonists do not acutely stimulate insulin release in rodents.

  15. Adipocyte-myocyte crosstalk in skeletal muscle insulin resistance; is there a role for thyroid hormone?

    Science.gov (United States)

    Havekes, Bas; Sauerwein, Hans P

    2010-11-01

    To review original research studies and reviews that present data on adipocyte-myocyte crosstalk in the development of skeletal muscle insulin resistance with a specific focus on thyroid hormone. Adipose tissue communicates with skeletal muscle not only through free fatty acids but also through secretion of various products called adipokines. Adipokines came out as governors of insulin sensitivity and are deregulated in obesity. In addition to well known leptin, adiponectin, interleukin-6 and tumor necrosis factor-alpha, newer adipokines like retinol-binding protein 4 have been associated with insulin resistance. There is mounting evidence that not only adipose tissue but also skeletal muscle produces and secretes biologically active proteins or 'myokines' that facilitate metabolic crosstalk between organ systems. In recent years, increased expression of myostatin, a secreted anabolic inhibitor of muscle growth and development, has been associated with obesity and insulin resistance. Both hypothyroidism and hyperthyroidism affect insulin sensitivity in multiple ways that might overlap adipocyte-myocyte crosstalk. Recent studies have provided new insights in effects of processing of the parent hormone T4 to the active T3 at the level of the skeletal muscle. Adipocyte-myocyte crosstalk is an important modulator in the development of skeletal muscle insulin resistance. Thyroid disorders are very common and may have detrimental effects on skeletal muscle insulin resistance, potentially by interacting with adipocyte-myocyte crosstalk.

  16. Insulin and GLP-1 infusions demonstrate the onset of adipose-specific insulin resistance in a large fasting mammal: potential glucogenic role for GLP-1.

    Science.gov (United States)

    Viscarra, Jose A; Rodriguez, Ruben; Vazquez-Medina, Jose Pablo; Lee, Andrew; Tift, Michael S; Tavoni, Stephen K; Crocker, Daniel E; Ortiz, Rudy M

    2013-08-01

    Prolonged food deprivation increases lipid oxidation and utilization, which may contribute to the onset of the insulin resistance associated with fasting. Because insulin resistance promotes the preservation of glucose and oxidation of fat, it has been suggested to be an adaptive response to food deprivation. However, fasting mammals exhibit hypoinsulinemia, suggesting that the insulin resistance-like conditions they experience may actually result from reduced pancreatic sensitivity to glucose/capacity to secrete insulin. To determine whether fasting results in insulin resistance or in pancreatic dysfunction, we infused early- and late-fasted seals (naturally adapted to prolonged fasting) with insulin (0.065 U/kg), and a separate group of late-fasted seals with low (10 pM/kg) or high (100 pM/kg) dosages of glucagon-like peptide-1 (GLP-1) immediately following a glucose bolus (0.5g/kg), and measured the systemic and cellular responses. Because GLP-1 facilitates glucose-stimulated insulin secretion, these infusions provide a method to assess pancreatic insulin-secreting capacity. Insulin infusions increased the phosphorylation of insulin receptor and Akt in adipose and muscle of early and late fasted seals; however the timing of the signaling response was blunted in adipose of late fasted seals. Despite the dose-dependent increases in insulin and increased glucose clearance (high dose), both GLP-1 dosages produced increases in plasma cortisol and glucagon, which may have contributed to the glucogenic role of GLP-1. Results suggest that fasting induces adipose-specific insulin resistance in elephant seal pups, while maintaining skeletal muscle insulin sensitivity, and therefore suggests that the onset of insulin resistance in fasting mammals is an evolved response to cope with prolonged food deprivation.

  17. Insulin resistance in obese children and adolescents.

    Science.gov (United States)

    Romualdo, Monica Cristina dos Santos; Nóbrega, Fernando José de; Escrivão, Maria Arlete Meil Schimith

    2014-01-01

    To evaluate the presence of insulin resistance and its association with other metabolic abnormalities in obese children and adolescents. Retrospective study of 220 children and adolescents aged 5-14 years. Anthropometric measurements were performed (weight, height, and waist circumference) and clinical (gender, age, pubertal stage, and degree of obesity) and biochemical (glucose, insulin, total cholesterol, and fractions, triglycerides) data were analyzed. Insulin resistance was identified by the homeostasis model assessment for insulin resistance (HOMA-IR) index. The analysis of the differences between the variables of interest and the HOMA-IR quartiles was performed by ANOVA or Kruskal-Wallis tests. Insulin resistance was diagnosed in 33.20% of the sample. It was associated with low levels of high-density lipoprotein cholesterol (HDL-C; p=0.044), waist circumference measurement (p=0.030), and the set of clinical and metabolic (p=0.000) alterations. Insulin-resistant individuals had higher mean age (p=0.000), body mass index (BMI; p=0.000), abdominal circumference (p=0.000), median triglycerides (p=0.001), total cholesterol (p≤0.042), and low-density lipoprotein cholesterol (LDL-C; p≤0.027); and lower HDL-C levels (p=0.005). There was an increase in mean BMI (p=0.000), abdominal circumference (p=0.000), and median triglycerides (p=0.002) as the values of HOMA -IR increased, with the exception of HDL-C, which decreased (p=0.001). Those with the highest number of simultaneous alterations were between the second and third quartiles of the HOMA-IR index (p=0.000). The results confirmed that insulin resistance is present in many obese children and adolescents, and that this condition is associated with alterations that represent an increased risk for developing metabolic disorders in adulthood. Copyright © 2014 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  18. Serum acylated ghrelin is negatively correlated with the insulin resistance in the CODING study.

    Directory of Open Access Journals (Sweden)

    Peyvand Amini

    Full Text Available Ghrelin is a 28-amino acid orexigenic peptide synthesized mainly in the stomach. Acute administration of ghrelin has been found to decrease insulin secretion. However, little data is available regarding whether ghrelin contributes to the long-term regulation of insulin resistance at the population level. The aim of this study is to investigate the association between circulating ghrelin and insulin resistance in a large population based study.A total of 2082 CODING study (Complex Diseases in the Newfoundland population: Environment and Genetics subjects were assessed. Subjects were of at least third generation Newfoundland descent, between the ages of 20 and 79 years, and had no serious metabolic, cardiovascular, or endocrine diseases. Ghrelin was measured with an Enzyme Immunoassay method. Insulin and fasting glucose were measured by Immulite 2500 autoanalyzer and Lx20 clinical chemistry analyzer, respectively. Homeostatic Model Assessment of β cell function (HOMA-β and Insulin Resistance (HOMA-IR and Quantitative Insulin-sensitivity Check Index (QUICKI were used for measurement of insulin resistance.Partial correlation analyses showed a significant negative correlation between circulating ghrelin and insulin level and insulin resistance in the entire cohort and also in men and women separately. The aforementioned correlation was independent of age, percentage of trunk fat and HDL-cholesterol. According to menopausal status, only pre-menopausal women revealed negative correlations.Our results suggest that except for postmenopausal women, high circulating ghrelin level is associated with lower insulin resistance in the general population.

  19. Synaptotagmin-7 phosphorylation mediates GLP-1-dependent potentiation of insulin secretion from β-cells

    DEFF Research Database (Denmark)

    Wu, Bingbing; Wei, Shunhui; Petersen, Natalia

    2015-01-01

    Glucose stimulates insulin secretion from β-cells by increasing intracellular Ca(2+). Ca(2+) then binds to synaptotagmin-7 as a major Ca(2+) sensor for exocytosis, triggering secretory granule fusion and insulin secretion. In type-2 diabetes, insulin secretion is impaired; this impairment...... is ameliorated by glucagon-like peptide-1 (GLP-1) or by GLP-1 receptor agonists, which improve glucose homeostasis. However, the mechanism by which GLP-1 receptor agonists boost insulin secretion remains unclear. Here, we report that GLP-1 stimulates protein kinase A (PKA)-dependent phosphorylation...... of synaptotagmin-7 at serine-103, which enhances glucose- and Ca(2+)-stimulated insulin secretion and accounts for the improvement of glucose homeostasis by GLP-1. A phospho-mimetic synaptotagmin-7 mutant enhances Ca(2+)-triggered exocytosis, whereas a phospho-inactive synaptotagmin-7 mutant disrupts GLP-1...

  20. Skeletal Muscle Insulin Resistance in Endocrine Disease

    Directory of Open Access Journals (Sweden)

    Melpomeni Peppa

    2010-01-01

    Full Text Available We summarize the existing literature data concerning the involvement of skeletal muscle (SM in whole body glucose homeostasis and the contribution of SM insulin resistance (IR to the metabolic derangements observed in several endocrine disorders, including polycystic ovary syndrome (PCOS, adrenal disorders and thyroid function abnormalities. IR in PCOS is associated with a unique postbinding defect in insulin receptor signaling in general and in SM in particular, due to a complex interaction between genetic and environmental factors. Adrenal hormone excess is also associated with disrupted insulin action in peripheral tissues, such as SM. Furthermore, both hyper- and hypothyroidism are thought to be insulin resistant states, due to insulin receptor and postreceptor defects. Further studies are definitely needed in order to unravel the underlying pathogenetic mechanisms. In summary, the principal mechanisms involved in muscle IR in the endocrine diseases reviewed herein include abnormal phosphorylation of insulin signaling proteins, altered muscle fiber composition, reduced transcapillary insulin delivery, decreased glycogen synthesis, and impaired mitochondrial oxidative metabolism.

  1. Autocrine effect of Zn²⁺ on the glucose-stimulated insulin secretion.

    Science.gov (United States)

    Slepchenko, Kira G; Daniels, Nigel A; Guo, Aili; Li, Yang V

    2015-09-01

    It is well known that zinc (Zn(2+)) is required for the process of insulin biosynthesis and the maturation of insulin secretory granules in pancreatic beta (β)-cells, and that changes in Zn(2+) levels in the pancreas have been found to be associated with diabetes. Glucose-stimulation causes a rapid co-secretion of Zn(2+) and insulin with similar kinetics. However, we do not know whether Zn(2+) regulates insulin availability and secretion. Here we investigated the effect of Zn(2+) on glucose-stimulated insulin secretion (GSIS) in isolated mouse pancreatic islets. Whereas Zn(2+) alone (control) had no effect on the basal secretion of insulin, it significantly inhibited GSIS. The application of CaEDTA, by removing the secreted Zn(2+) from the extracellular milieu of the islets, resulted in significantly increased GSIS, suggesting an overall inhibitory role of secreted Zn(2+) on GSIS. The inhibitory action of Zn(2+) was mostly mediated through the activities of KATP/Ca(2+) channels. Furthermore, during brief paired-pulse glucose-stimulated Zn(2+) secretion (GSZS), Zn(2+) secretion following the second pulse was significantly attenuated, probably by the secreted endogenous Zn(2+) after the first pulse. Such an inhibition on Zn(2+) secretion following the second pulse was completely reversed by Zn(2+) chelation, suggesting a negative feedback mechanism, in which the initial glucose-stimulated Zn(2+) release inhibits subsequent Zn(2+) secretion, subsequently inhibiting insulin co-secretion as well. Taken together, these data suggest a negative feedback mechanism on GSZS and GSIS by Zn(2+) secreted from β-cells, and the co-secreted Zn(2+) may act as an autocrine inhibitory modulator.

  2. Molecular mechanisms of insulin resistance

    African Journals Online (AJOL)

    Review Article. ,. Molecular ... This review discusses recent advances in understanding of the structure and ... insulin action from receptor to the alteration of blood glucose. Hence, in ... the first protein to have its amino acid sequence determined;2 ... an integral membrane glycoprotein composed of two subunits, a and 13 ...

  3. Mechanism of insulin resistance in normal pregnancy.

    Science.gov (United States)

    Hodson, K; Man, C Dalla; Smith, F E; Thelwall, P E; Cobelli, C; Robson, S C; Taylor, R

    2013-08-01

    Normal pregnancy is associated with insulin resistance although the mechanism is not understood. Increased intramyocellular lipid is closely associated with the insulin resistance of type 2 diabetes and obesity, and the aim of this study was to determine whether this was so for the physiological insulin resistance of pregnancy. Eleven primiparous healthy pregnant women (age: 27-39 years, body mass index 24.0±3.1 kg/m2) and no personal or family history of diabetes underwent magnetic resonance studies to quantify intramyocellular lipid, plasma lipid fractions, and insulin sensitivity. The meal-related insulin sensitivity index was considerably lower in pregnancy (45.6±9.9 vs. 193.0±26.1; 10(-4) dl/kg/min per pmol/l, p=0.0002). Fasting plasma triglyceride levels were elevated 3-fold during pregnancy (2.3±0.2 vs. 0.8±0.1 mmol/l, pinsulin resistance is distinct from that underlying type 2 diabetes. © Georg Thieme Verlag KG Stuttgart · New York.

  4. Environmental factors and dam characteristics associated with insulin sensitivity and insulin secretion in newborn Holstein calves

    International Nuclear Information System (INIS)

    Kamal, M.M.; Van Eetvelde, M.; Bogaert, H.; Hostens, M.; Vandaele, L.; Shamsuddin, M.; Opsomer, G.

    2016-01-01

    Full text: The objective of the present retrospective cohort study was to evaluate potential associations between environmental factors and dam characteristics, including level of milk production during gestation, and insulin traits in newborn Holstein calves. Birth weight and gestational age of the calves at delivery were determined. On the next day, heart girth, wither height and diagonal length of both the calves and their dams were measured. Parity, body condition score and age at calving were recorded for all dams. For the cows, days open before last gestation, lactation length (LL), lenght of dry period (DP) and calving interval were also calculated. The magnitude and shape of the lactation curve both quantified using the MilkBot model based on monthly milk weights, were used to calculate the amount of milk produced during gestation. Using the same procedure, cumulative milk production from conception to drying off (MGEST) was calculated. A blood sample was collected from all calves (n=481; 169 born to heifers and 312 born to cows) at least 5 h after a milk meal on day 3 of life to measure basal glucose and insulin levels. In addition, an intravenous glucose-stimulated insulin secretion test was performed in a subset of the calves (n=316). After descriptive analysis, generalized linear mixed models were used to identify factors that were significantly associated with the major insulin traits (Insb, basal insulin level; QUICKI, quantitative insulin sensitivity check index; AIR, acute insulin response; DI, disposition index) of the newborn calves. The overall average birth weight of the calves was 42.7 ± 5.92 kg. The insulin traits were significantly associated with MGEST (P=0.076) and longer DP (P=0.034). The QUICKI was estimated to be lower in calves born to the cows having passed a higher MGEST (P=0.030) and longer DP (P=0.058). Moreover, the AIR (P=0.009) and DI (P=0.049) were estimated to be lower in male compared with female calves. Furthermore, the AIR

  5. Trajectories of glycaemia, insulin sensitivity and insulin secretion in South Asian and white individuals before diagnosis of type 2 diabetes

    DEFF Research Database (Denmark)

    Hulman, Adam; Simmons, Rebecca K; Brunner, Eric J

    2017-01-01

    AIMS/HYPOTHESIS: South Asian individuals have reduced insulin sensitivity and increased risk of type 2 diabetes compared with white individuals. Temporal changes in glycaemic traits during middle age suggest that impaired insulin secretion is a particular feature of diabetes development among South...... Asians. We therefore aimed to examine ethnic differences in early changes in glucose metabolism prior to incident type 2 diabetes. METHODS: In a prospective British occupational cohort, subject to 5 yearly clinical examinations, we examined ethnic differences in trajectories of fasting plasma glucose...... (FPG), 2 h post-load plasma glucose (2hPG), fasting serum insulin (FSI), 2 h post-load serum insulin (2hSI), HOMA of insulin sensitivity (HOMA2-S) and secretion (HOMA2-B), and the Gutt insulin sensitivity index (ISI0,120) among 120 South Asian and 867 white participants who developed diabetes during...

  6. Metabolism and insulin signaling in common metabolic disorders and inherited insulin resistance

    DEFF Research Database (Denmark)

    Højlund, Kurt

    2014-01-01

    . These metabolic disorders are all characterized by reduced plasma adiponectin and insulin resistance in peripheral tissues. Quantitatively skeletal muscle is the major site of insulin resistance. Both low plasma adiponectin and insulin resistance contribute to an increased risk of type 2 diabetes...... described a novel syndrome characterized by postprandial hyperinsulinemic hypoglycemia and insulin resistance. This syndrome is caused by a mutation in the tyrosine kinase domain of the insulin receptor gene (INSR). We have studied individuals with this mutation as a model of inherited insulin resistance....... Type 2 diabetes, obesity and PCOS are characterized by pronounced defects in the insulin-stimulated glucose uptake, in particular glycogen synthesis and to a lesser extent glucose oxidation, and the ability of insulin to suppress lipid oxidation. In inherited insulin resistance, however, only insulin...

  7. Molecular mechanisms of insulin resistance | Pillay | South African ...

    African Journals Online (AJOL)

    This review discusses recent advances in understanding of the structure and function of the insulin receptor and insulin action, and how these relate to the clinical aspects of insulin resistance associated with non-insulin-dependent diabetes and other disorders. Improved understanding of the molecular basis of insulin ...

  8. Observations on the insulin-secretion function in the offsprings of patients with type II diabetes

    International Nuclear Information System (INIS)

    Xu Shujie; Tian Xiaoping; Wu Yan

    2004-01-01

    Objective: To investigate the disturbance of insulin-secretion function in the offsprings of patients with type II diabetes. Methods: Blood sugar (with oxidase method) and insulin (with RIA) levels were measured after overnight fasting and repeatedly measured 2h after 75g glucose per oral in the following subjects: 1) Group A, 23 non-obese offsprings of type II diabetics 2) group B, 18 obese offsprings (BMI ≥25kg/m 2 ) and 3) 27 controls. Homeostatic model assessment-insulin resistance (HOMA-IR) and β-cell function index (HCI) were calculated from the data (glucose and insulin levels) obtained. Results: For Group A subjects, the fasting blood sugar (FPG) levels were significantly higher and HBCI significantly lower than those in te controls (both P<0.05). For Group B obese subjects, in addition to the above two parameters (with HBCI P<0.01), 2h PG levels as well as HOMA-IR were also significantly higher (both P<0.05). Conclusion: Present study showed that in the offsprings of diabetics, HBCI was already lowered before definite impaired glucose tolerance (IGT) could be demonstrated, especially in the obese ones. (authors)

  9. Observations on the insulin-secretion function in the offsprings of patients with type II diabetes

    Energy Technology Data Exchange (ETDEWEB)

    Shujie, Xu; Xiaoping, Tian; Yan, Wu [The First People' s Hospital of Lianyungang (China)

    2004-10-01

    Objective: To investigate the disturbance of insulin-secretion function in the offsprings of patients with type II diabetes. Methods: Blood sugar (with oxidase method) and insulin (with RIA) levels were measured after overnight fasting and repeatedly measured 2h after 75g glucose per oral in the following subjects: 1) Group A, 23 non-obese offsprings of type II diabetics 2) group B, 18 obese offsprings (BMI {>=}25kg/m{sup 2} ) and 3) 27 controls. Homeostatic model assessment-insulin resistance (HOMA-IR) and {beta}-cell function index (HCI) were calculated from the data (glucose and insulin levels) obtained. Results: For Group A subjects, the fasting blood sugar (FPG) levels were significantly higher and HBCI significantly lower than those in te controls (both P<0.05). For Group B obese subjects, in addition to the above two parameters (with HBCI P<0.01), 2h PG levels as well as HOMA-IR were also significantly higher (both P<0.05). Conclusion: Present study showed that in the offsprings of diabetics, HBCI was already lowered before definite impaired glucose tolerance (IGT) could be demonstrated, especially in the obese ones. (authors)

  10. An ancestral role for the mitochondrial pyruvate carrier in glucose-stimulated insulin secretion

    Directory of Open Access Journals (Sweden)

    Kyle S. McCommis

    2016-08-01

    Full Text Available Objective: Transport of pyruvate into the mitochondrial matrix by the Mitochondrial Pyruvate Carrier (MPC is an important and rate-limiting step in its metabolism. In pancreatic β-cells, mitochondrial pyruvate metabolism is thought to be important for glucose sensing and glucose-stimulated insulin secretion. Methods: To evaluate the role that the MPC plays in maintaining systemic glucose homeostasis, we used genetically-engineered Drosophila and mice with loss of MPC activity in insulin-producing cells. Results: In both species, MPC deficiency results in elevated blood sugar concentrations and glucose intolerance accompanied by impaired glucose-stimulated insulin secretion. In mouse islets, β-cell MPC-deficiency resulted in decreased respiration with glucose, ATP-sensitive potassium (KATP channel hyperactivity, and impaired insulin release. Moreover, treatment of pancreas-specific MPC knockout mice with glibenclamide, a sulfonylurea KATP channel inhibitor, improved defects in islet insulin secretion and abnormalities in glucose homeostasis in vivo. Finally, using a recently-developed biosensor for MPC activity, we show that the MPC is rapidly stimulated by glucose treatment in INS-1 insulinoma cells suggesting that glucose sensing is coupled to mitochondrial pyruvate carrier activity. Conclusions: Altogether, these studies suggest that the MPC plays an important and ancestral role in insulin-secreting cells in mediating glucose sensing, regulating insulin secretion, and controlling systemic glycemia. Keywords: Stimulus-coupled secretion, Insulin, β-Cell, Diabetes, Pyruvate, Mitochondria, Drosophila

  11. Insulin-mediated increases in renal plasma flow are impaired in insulin-resistant normal subjects

    NARCIS (Netherlands)

    ter Maaten, JC; Bakker, SJL; Serne, EH; Moshage, HJ; Gans, ROB

    2000-01-01

    Background Impaired vasodilatation in skeletal muscle is a possible mechanism linking insulin resistance to blood pressure regulation. Increased renal vascular resistance has been demonstrated in the offspring of essential hypertensives. We assessed whether insulin-mediated renal vasodilatation is

  12. Exercise Increases Insulin Content and Basal Secretion in Pancreatic Islets in Type 1 Diabetic Mice

    Directory of Open Access Journals (Sweden)

    Han-Hung Huang

    2011-01-01

    Full Text Available Exercise appears to improve glycemic control for people with type 1 diabetes (T1D. However, the mechanism responsible for this improvement is unknown. We hypothesized that exercise has a direct effect on the insulin-producing islets. Eight-week-old mice were divided into four groups: sedentary diabetic, exercised diabetic, sedentary control, and exercised control. The exercised groups participated in voluntary wheel running for 6 weeks. When compared to the control groups, the islet density, islet diameter, and β-cell proportion per islet were significantly lower in both sedentary and exercised diabetic groups and these alterations were not improved with exercise. The total insulin content and insulin secretion were significantly lower in sedentary diabetics compared to controls. Exercise significantly improved insulin content and insulin secretion in islets in basal conditions. Thus, some improvements in exercise-induced glycemic control in T1D mice may be due to enhancement of insulin content and secretion in islets.

  13. Increased androgen levels in rats impair glucose-stimulated insulin secretion through disruption of pancreatic beta cell mitochondrial function.

    Science.gov (United States)

    Wang, Hongdong; Wang, Xiaping; Zhu, Yunxia; Chen, Fang; Sun, Yujie; Han, Xiao

    2015-11-01

    Although insulin resistance is recognized to contribute to the reproductive and metabolic phenotypes of polycystic ovary syndrome (PCOS), pancreatic beta cell dysfunction plays an essential role in the progression from PCOS to the development of type 2 diabetes. However, the role of insulin secretory abnormalities in PCOS has received little attention. In addition, the precise changes in beta cells and the underlying mechanisms remain unclear. In this study, we therefore attempted to elucidate potential mechanisms involved in beta cell alterations in a rat model of PCOS. Glucose-induced insulin secretion was measured in islets isolated from DHT-treated and control rats. Oxygen consumption rate (OCR), ATP production, and mitochondrial copy number were assayed to evaluate mitochondrial function. Glucose-stimulated insulin secretion is significantly decreased in islets from DHT-treated rats. On the other hand, significant reductions are observed in the expression levels of several key genes involved in mitochondrial biogenesis and in mitochondrial OCR and ATP production in DHT-treated rat islets. Meanwhile, we found that androgens can directly impair beta cell function by inducing mitochondrial dysfunction in vitro in an androgen receptor dependent manner. For the first time, our study demonstrates that increased androgens in female rats can impair glucose-stimulated insulin secretion partly through disruption of pancreatic beta cell mitochondrial function. This work has significance for hyperandrogenic women with PCOS: excess activation of the androgen receptor by androgens may provoke beta cell dysfunction via mitochondrial dysfunction. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Hematopoietic-Derived Galectin-3 Causes Cellular and Systemic Insulin Resistance.

    Science.gov (United States)

    Li, Pingping; Liu, Shuainan; Lu, Min; Bandyopadhyay, Gautum; Oh, Dayoung; Imamura, Takeshi; Johnson, Andrew M F; Sears, Dorothy; Shen, Zhufang; Cui, Bing; Kong, Lijuan; Hou, Shaocong; Liang, Xiao; Iovino, Salvatore; Watkins, Steven M; Ying, Wei; Osborn, Olivia; Wollam, Joshua; Brenner, Martin; Olefsky, Jerrold M

    2016-11-03

    In obesity, macrophages and other immune cells accumulate in insulin target tissues, promoting a chronic inflammatory state and insulin resistance. Galectin-3 (Gal3), a lectin mainly secreted by macrophages, is elevated in both obese subjects and mice. Administration of Gal3 to mice causes insulin resistance and glucose intolerance, whereas inhibition of Gal3, through either genetic or pharmacologic loss of function, improved insulin sensitivity in obese mice. In vitro treatment with Gal3 directly enhanced macrophage chemotaxis, reduced insulin-stimulated glucose uptake in myocytes and 3T3-L1 adipocytes and impaired insulin-mediated suppression of glucose output in primary mouse hepatocytes. Importantly, we found that Gal3 can bind directly to the insulin receptor (IR) and inhibit downstream IR signaling. These observations elucidate a novel role for Gal3 in hepatocyte, adipocyte, and myocyte insulin resistance, suggesting that Gal3 can link inflammation to decreased insulin sensitivity. Inhibition of Gal3 could be a new approach to treat insulin resistance. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Hippocampal insulin resistance and cognitive dysfunction

    NARCIS (Netherlands)

    Biessels, Geert Jan; Reagan, Lawrence P.

    2015-01-01

    Clinical studies suggest a link between type 2 diabetes mellitus (T2DM) and insulin resistance (IR) and cognitive dysfunction, but there are significant gaps in our knowledge of the mechanisms underlying this relationship. Animal models of IR help to bridge these gaps and point to hippocampal IR as

  16. Mitochondrial adaptations in insulin resistant muscle

    NARCIS (Netherlands)

    Broek, van den N.M.A.

    2010-01-01

    Diabetes has reached epidemic proportions worldwide. Type 2 diabetes (T2D) accounts for about 90% of all diabetes cases and is characterized by insulin resistance (IR) in major metabolic tissues. The dramatic rise in T2D is associated with the increased occurrence of obesity and excessive ectopic

  17. Insulin resistance induced by antiretroviral drugs: Current ...

    African Journals Online (AJOL)

    Treatment with highly active antiretroviral therapy (HAART) has improved the prognosis of patients with AIDS, but it has also increased the incidence of various metabolic disorders, in particular insulin resistance accompanied by dyslipidaemia, hyperglycaemia and lipodystrophy. This is often accompanied by frank type 2 ...

  18. Osteocalcin improves insulin resistance and inflammation in obese mice: Participation of white adipose tissue and bone.

    Science.gov (United States)

    Guedes, J A C; Esteves, J V; Morais, M R; Zorn, T M; Furuya, D T

    2017-11-26

    The discovery of osteocalcin, a protein synthetized by osteoblasts, as a hormone that has positive effects on insulin resistance, contributed to support the concept of bone as an endocrine organ. However, very little is known about the molecular pathways involved in osteocalcin improved-insulin resistance. The present study aimed to investigate the mechanisms of action of osteocalcin on insulin resistance and inflammation in obese mice and 3T3-L1 adipocytes. Lean control, saline-treated obese and uncarboxylated osteocalcin (uOC)-treated obese mice were subjected to insulin tolerance test in vivo. Blood was collect for biochemical/metabolic profile analysis; and, skeletal muscle, white adipose tissue (WAT) and bone were collected for protein (Western blotting) and mRNA (RT-qPCR) analysis. uOC effects on insulin resistance and inflammation were also investigated in 3T3-L1 adipocytes challenged with tumor necrosis factor. Osteocalcin treatment improved in vivo insulin resistance in obese mice. In WAT, osteocalcin had positive effects such as (1) WAT weight reduction; (2) upregulation of glucose transporter (GLUT) 4 protein and its mRNA (Slc2a4); (3) improved insulin-induced AKT phosphorylation; (4) downregulation of several genes involved in inflammation and inflammassome transcriptional machinery, and (5) reduction of the density of macrophage in crown-like structures (histomorphometrical analysis). Notably, in 3T3-L1 adipocytes, osteocalcin restored Slc2a4/GLUT4 content and reduced the expression of inflammatory genes after TNF-a challenge; moreover, osteocalcin treatment increased AKT phosphorylation induced by insulin. Finally, it was observed that in bone, osteocalcin improves insulin resistance by increasing insulin-induced AKT phosphorylation and reducing the expression of genes involved in bone insulin resistance, resulting in increased secretion of uncarboxylated osteocalcin in circulation. We provided some mechanisms of action for osteocalcin in the

  19. Role of reduced insulin-stimulated bone blood flow in the pathogenesis of metabolic insulin resistance and diabetic bone fragility.

    Science.gov (United States)

    Hinton, Pamela S

    2016-08-01

    Worldwide, 387 million adults live with type 2 diabetes (T2D) and an additional 205 million cases are projected by 2035. Because T2D has numerous complications, there is significant morbidity and mortality associated with the disease. Identification of early events in the pathogenesis of insulin resistance and T2D might lead to more effective treatments that would mitigate health and monetary costs. Here, we present our hypothesis that impaired bone blood flow is an early event in the pathogenesis of whole-body metabolic insulin resistance that ultimately leads to T2D. Two recent developments in different fields form the basis for this hypothesis. First, reduced vascular function has been identified as an early event in the development of T2D. In particular, before the onset of tissue or whole body metabolic insulin resistance, insulin-stimulated, endothelium-mediated skeletal muscle blood flow is impaired. Insulin resistance of the vascular endothelium reduces delivery of insulin and glucose to skeletal muscle, which leads to tissue and whole-body metabolic insulin resistance. Second is the paradigm-shifting discovery that the skeleton has an endocrine function that is essential for maintenance of whole-body glucose homeostasis. Specifically, in response to insulin signaling, osteoblasts secret osteocalcin, which stimulates pancreatic insulin production and enhances insulin sensitivity in skeletal muscle, adipose, and liver. Furthermore, the skeleton is not metabolically inert, but contributes to whole-body glucose utilization, consuming 20% that of skeletal muscle and 50% that of white adipose tissue. Without insulin signaling or without osteocalcin activity, experimental animals become hyperglycemic and insulin resistant. Currently, it is not known if insulin-stimulated, endothelium-mediated blood flow to bone plays a role in the development of whole body metabolic insulin resistance. We hypothesize that it is a key, early event. Microvascular dysfunction is a

  20. Fine-mapping diabetes-related traits, including insulin resistance, in heterogeneous stock rats

    Science.gov (United States)

    Holl, Katie L.; Oreper, Daniel; Xie, Yuying; Tsaih, Shirng-Wern; Valdar, William

    2012-01-01

    Type 2 diabetes (T2D) is a disease of relative insulin deficiency resulting from both insulin resistance and beta cell failure. We have previously used heterogeneous stock (HS) rats to fine-map a locus for glucose tolerance. We show here that glucose intolerance in the founder strains of the HS colony is mediated by different mechanisms: insulin resistance in WKY and an insulin secretion defect in ACI, and we demonstrate a high degree of variability for measures of insulin resistance and insulin secretion in HS rats. As such, our goal was to use HS rats to fine-map several diabetes-related traits within a region on rat chromosome 1. We measured blood glucose and plasma insulin levels after a glucose tolerance test in 782 male HS rats. Using 97 SSLP markers, we genotyped a 68 Mb region on rat chromosome 1 previously implicated in glucose and insulin regulation. We used linkage disequilibrium mapping by mixed model regression with inferred descent to identify a region from 198.85 to 205.9 that contains one or more quantitative trait loci (QTL) for fasting insulin and a measure of insulin resistance, the quantitative insulin sensitivity check index. This region also encompasses loci identified for fasting glucose and Insulin_AUC (area under the curve). A separate <3 Mb QTL was identified for body weight. Using a novel penalized regression method we then estimated effects of alternative haplotype pairings under each locus. These studies highlight the utility of HS rats for fine-mapping genetic loci involved in the underlying causes of T2D. PMID:22947656

  1. Absence of down-regulation of the insulin receptor by insulin. A possible mechanism of insulin resistance in the rat.

    OpenAIRE

    Walker, A P; Flint, D J

    1983-01-01

    Insulin resistance occurs in rat adipocytes during pregnancy and lactation despite increased or normal insulin binding respectively; this suggests that a post-receptor defect exists. The possibility has been examined that, although insulin binding occurs normally, internalization of insulin or its receptor may be impaired in these states. Insulin produced a dose-dependent reduction in the number of insulin receptors on adipocytes from virgin rats maintained in culture medium, probably due to ...

  2. Decrease of glucose-induced insulin secretion of rat pancreatic islets after irradiation in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Heinzmann, D; Nadrowitz, R; Besch, W; Schmidt, W; Hahn, H J [Zentralinstitut fuer Diabetes, Karlsburg (German Democratic Republic); Ernst-Moritz-Arndt-Universitaet, Greifswald (German Democratic Republic). Radiologische Klinik)

    1983-01-01

    In vitro irradiation of rat pancreatic islets up to a dose of 2.5 Gy did neither alter glucose- nor isobutylmethyl xanthine (IBMX)-induced insulin secretion. Insulin as well as glucagon content of irradiated islets corresponded to that of the control tissue. So it was in islets irradiated with 25 Gy which were characterized by a decreased insulin secretion in the presence of glucose and IBMX, respectively. There was no indication of an enhanced hormone output in the radiation medium and it is to be suggested that higher radiation doses affect the insulin release of pancreatic islets in vitro. This must be taken into consideration for radioimmunosuppression experiments.

  3. Pregestational diabetes with extreme insulin resistance: use of U-500 insulin in pregnancy.

    Science.gov (United States)

    Zuckerwise, Lisa C; Werner, Erika F; Pettker, Christian M; McMahon-Brown, Erin K; Thung, Stephen F; Han, Christina S

    2012-08-01

    Increased insulin requirements in pregnancy can hinder attainment of glycemic control in diabetic patients. U-500 insulin is a concentrated form of regular insulin that can be a valuable tool in the treatment of patients with severe insulin resistance. A 24-year-old woman with pregestational diabetes mellitus experienced increasing insulin requirements during pregnancy, peaking at 650 units daily. The frequent, large-volume injections of standard-concentration insulin were poorly tolerated by the patient and resulted in nonadherence. She subsequently achieved glycemic control on thrice-daily U-500 insulin. Pregnancy exacerbates insulin resistance in diabetic patients, and these patients may require high doses of insulin. U-500 insulin is an effective alternative for patients with severe insulin resistance and should be considered for pregnant women with difficulty achieving glycemic control.

  4. Effect of cholecalciferol and levo carnitine on plasma glucose, plasma insulin and insulin resistance in type 2 diabetic rats

    International Nuclear Information System (INIS)

    Anwar, M. K.; Hussain, M. M.; Khan, M. A.; Ahmad, T.

    2013-01-01

    Objective: To compare the effects of combined and individual supplementation of cholecalciferol and levo carnitine on plasma glucose, plasma insulin and insulin resistance in type 2 diabetic rats. Methods: The randomised controlled trial was conducted at the Department of Physiology, Army Medical College, Rawalpindi, between October 2010 and April 2011. It comprised 80 healthy Sprague Dawley rats who were divided into four groups (n = 20 each). Rats were fed high-fat diet for 2 weeks followed by an intraperitoneal injection of streptozocin to induce type 2 diabetes mellitus. Group I served as diabetic control; group II was given cholecalciferol; group III; levo carnitine; and group IV was administered cholecalciferol and levo carnitine together. After 6 days of supplementation, terminal intracardiac blood extraction was done and samples were analysed for fasting plasma glucose and plasma insulin. Insulin resistance was calculated by homeostatic model assessment for insulin resistance. SPSS 17.0 was used for statistical analysis. Results: Fasting plasma glucose levels were significantly decreased (p <0.001) in the combined supplementation group compared to the diabetic control and individual supplementation groups. Combined supplementation showed a significant increase in fasting plasma insulin levels when compared with diabetic control and levo carnitine groups (p <0.001), and the effect of combined supplementation on ameliorating insulin resistance was significantly better (p <0.001) as compared to the individual supplementation of cholecalciferol and levo carnitine. Conclusions: The combined supplementation of cholecalciferol and levo carnitine for 6 days markedly improved the glycaemic control, insulin secretion and insulin resistance in type 2 diabetic rats on high-fat diet. A prolonged supplementation by both the compounds along with caloric restriction may yield a more promising outcome. (author)

  5. Urea impairs β cell glycolysis and insulin secretion in chronic kidney disease

    Science.gov (United States)

    Koppe, Laetitia; Nyam, Elsa; Vivot, Kevin; Manning Fox, Jocelyn E.; Dai, Xiao-Qing; Nguyen, Bich N.; Attané, Camille; Moullé, Valentine S.; MacDonald, Patrick E.; Ghislain, Julien

    2016-01-01

    Disorders of glucose homeostasis are common in chronic kidney disease (CKD) and are associated with increased mortality, but the mechanisms of impaired insulin secretion in this disease remain unclear. Here, we tested the hypothesis that defective insulin secretion in CKD is caused by a direct effect of urea on pancreatic β cells. In a murine model in which CKD is induced by 5/6 nephrectomy (CKD mice), we observed defects in glucose-stimulated insulin secretion in vivo and in isolated islets. Similarly, insulin secretion was impaired in normal mouse and human islets that were cultured with disease-relevant concentrations of urea and in islets from normal mice treated orally with urea for 3 weeks. In CKD mouse islets as well as urea-exposed normal islets, we observed an increase in oxidative stress and protein O-GlcNAcylation. Protein O-GlcNAcylation was also observed in pancreatic sections from CKD patients. Impairment of insulin secretion in both CKD mouse and urea-exposed islets was associated with reduced glucose utilization and activity of phosphofructokinase 1 (PFK-1), which could be reversed by inhibiting O-GlcNAcylation. Inhibition of O-GlcNAcylation also restored insulin secretion in both mouse models. These results suggest that insulin secretory defects associated with CKD arise from elevated circulating levels of urea that increase islet protein O-GlcNAcylation and impair glycolysis. PMID:27525435

  6. Novel insulin from the bullfrog: its structure and function in protein secretion by hepatocytes

    International Nuclear Information System (INIS)

    Hulsebus, J.J.

    1987-01-01

    Bullfrog insulin was extracted and purified from the pancreas of Rana catesbeiana adults using gel filtration and reverse phase high performance liquid chromatography. Amino acid analysis of bullfrog insulin revealed 52 amino acids instead of the most common number of 51. The most unique features of bullfrog insulin is a two amino acid extension on the amino terminus (A1) of the A chain. This is the only insulin to date that has an extension at this position. Bullfrog and porcine insulin increase protein secretion from bullfrog adult and three developmental stages of tadpole hepatocytes in a totally defined, serum-free culture system. The hormone slightly stimulates protein secretion by premetamorphic and early prometamorphic tadpoles. Late prometamorphic tadpoles respond to bullfrog and porcine insulin with higher concentrations of secreted protein than either of the two previous developmental stages. Insulin treated adult hepatocytes secrete significantly higher concentrations of protein than any of the tadpole stages. 35 S-methionine and 35 S-cysteine were added to the culture medium for twelve hours. Proteins secreted into the medium were separated using SDS polyacrylamide linear gradient gels. Densitometer scans of autoradiograms did not show an increases in any specific proteins, but did show a generalized increase in all secreted proteins for both adults, and tadpoles

  7. MODELS OF INSULIN RESISTANCE AND HEART FAILURE

    Science.gov (United States)

    Velez, Mauricio; Kohli, Smita; Sabbah, Hani N.

    2013-01-01

    The incidence of heart failure (HF) and diabetes mellitus is rapidly increasing and is associated with poor prognosis. In spite of the advances in therapy, HF remains a major health problem with high morbidity and mortality. When HF and diabetes coexist, clinical outcomes are significantly worse. The relationship between these two conditions has been studied in various experimental models. However, the mechanisms for this interrelationship are complex, incompletely understood, and have become a matter of considerable clinical and research interest. There are only few animal models that manifest both HF and diabetes. However, the translation of results from these models to human disease is limited and new models are needed to expand our current understanding of this clinical interaction. In this review, we discuss mechanisms of insulin signaling and insulin resistance, the clinical association between insulin resistance and HF and its proposed pathophysiologic mechanisms. Finally, we discuss available animal models of insulin resistance and HF and propose requirements for future new models. PMID:23456447

  8. Fatty Acids, Obesity and Insulin Resistance

    Directory of Open Access Journals (Sweden)

    Peter Arner

    2015-04-01

    Full Text Available Objective: Although elevated free fatty acid (FFA levels in obesity have been considered to be of importance for insulin resistance, a recent meta-analysis suggested normal FFA levels in obese subjects. We investigated fasting circulating FFA and glycerol levels in a large cohort of non-obese and obese subjects. Methods: Subjects recruited for a study on obesity genetics were investigated in the morning after an overnight fast (n = 3,888. Serum FFA (n = 3,306, plasma glycerol (n = 3,776, and insulin sensitivity index (HOMA-IR,n = 3,469 were determined. Obesity was defined as BMI ≥ 30 kg/m2 and insulin resistance as HOMA-IR ≥ 2.21. Results: In obese subjects, circulating FFA and glycerol levels were higher than in non-obese individuals (by 26% and 47%, respectively; both p Conclusion: Circulating FFA and glycerol levels are markedly elevated in obesity but only marginally influenced by insulin resistance and type 2 diabetes. Whether these differences persist during diurnal variations in circulating FFA/glycerol, remains to be established.

  9. Momordica charantia Administration Improves Insulin Secretion in Type 2 Diabetes Mellitus.

    Science.gov (United States)

    Cortez-Navarrete, Marisol; Martínez-Abundis, Esperanza; Pérez-Rubio, Karina G; González-Ortiz, Manuel; Villar, Miriam Méndez-Del

    2018-02-12

    An improvement in parameters of glycemic control has been observed with Momordica charantia in patients with type 2 diabetes mellitus (T2DM). It is unknown whether this improvement is through a modification of insulin secretion, insulin sensitivity, or both. We hypothesized that M. charantia administration can improve insulin secretion and/or insulin sensitivity in patients with T2DM, without pharmacological treatment. The objective of the study was to evaluate the effect of M. charantia administration on insulin secretion and sensitivity. A randomized, double-blinded, placebo-controlled, clinical trial was carried out in 24 patients who received M. charantia (2000 mg/day) or placebo for 3 months. A 2-h oral glucose tolerance test (OGTT) was done before and after the intervention to calculate areas under the curve (AUC) of glucose and insulin, total insulin secretion (insulinogenic index), first phase of insulin secretion (Stumvoll index), and insulin sensitivity (Matsuda index). In the M. charantia group, there were significant decreases in weight, body mass index (BMI), fat percentage, waist circumference (WC), glycated hemoglobin A1c (A1C), 2-h glucose in OGTT, and AUC of glucose. A significant increase in insulin AUC (56,562 ± 36,078 vs. 65,256 ± 42,720 pmol/L/min, P = .043), in total insulin secretion (0.29 ± 0.18 vs. 0.41 ± 0.29, P = .028), and during the first phase of insulin secretion (557.8 ± 645.6 vs. 1135.7 ± 725.0, P = .043) was observed after M. charantia administration. Insulin sensitivity was not modified with any intervention. In conclusion, M. charantia administration reduced A1C, 2-h glucose, glucose AUC, weight, BMI, fat percentage, and WC, with an increment of insulin AUC, first phase and total insulin secretion.

  10. Effect of Human Myotubes-Derived Media on Glucose-Stimulated Insulin Secretion

    Directory of Open Access Journals (Sweden)

    Maria L. Mizgier

    2017-01-01

    Full Text Available Fasting to postprandial transition requires a tight adjustment of insulin secretion to its demand, so tissue (e.g., skeletal muscle glucose supply is assured while hypo-/hyperglycemia are prevented. High muscle glucose disposal after meals is pivotal for adapting to increased glycemia and might drive insulin secretion through muscle-released factors (e.g., myokines. We hypothesized that insulin influences myokine secretion and then increases glucose-stimulated insulin secretion (GSIS. In conditioned media from human myotubes incubated with/without insulin (100 nmol/L for 24 h, myokines were qualitatively and quantitatively characterized using an antibody-based array and ELISA-based technology, respectively. C57BL6/J mice islets and Wistar rat beta cells were incubated for 24 h with control and conditioned media from noninsulin- and insulin-treated myotubes prior to GSIS determination. Conditioned media from insulin-treated versus nontreated myotubes had higher RANTES but lower IL6, IL8, and MCP1 concentration. Qualitative analyses revealed that conditioned media from noninsulin- and insulin-treated myotubes expressed 32 and 23 out of 80 myokines, respectively. Islets incubated with conditioned media from noninsulin-treated myotubes had higher GSIS versus control islets (p<0.05. Meanwhile, conditioned media from insulin-treated myotubes did not influence GSIS. In beta cells, GSIS was similar across conditions. In conclusion, factors being present in noninsulin-stimulated muscle cell-derived media appear to influence GSIS in mice islets.

  11. Pancreatic β-Cell Electrical Activity and Insulin Secretion: of Mice and Men

    Science.gov (United States)

    Rorsman, Patrik; Ashcroft, Frances M

    2018-01-01

    The pancreatic β-cell plays a key role in glucose homeostasis by secreting insulin, the only hormone capable of lowering the blood glucose concentration. Impaired insulin secretion results in the chronic hyperglycaemia that characterizes type 2 diabetes (T2DM), which currently afflicts >450 million people worldwide. The healthy β-cell acts as a glucose sensor matching its output to the circulating glucose concentration. It does so via metabolically induced changes in electrical activity, which culminate in an increase in the cytoplasmic Ca2+ concentration and initiation of Ca2+-dependent exocytosis of insulin-containing secretory granules. Here, we review recent advances in our understanding of the β-cell transcriptome, electrical activity and insulin exocytosis. We highlight salient differences between mouse and human β-cells, provide models of how the different ion channels contribute to their electrical activity and insulin secretion, and conclude by discussing how these processes become perturbed in T2DM. PMID:29212789

  12. Monomeric tartrate resistant acid phosphatase induces insulin sensitive obesity.

    Directory of Open Access Journals (Sweden)

    Pernilla Lång

    2008-03-01

    Full Text Available Obesity is associated with macrophage infiltration of adipose tissue, which may link adipose inflammation to insulin resistance. However, the impact of inflammatory cells in the pathophysiology of obesity remains unclear. Tartrate resistant acid phosphatase (TRAP is an enzyme expressed by subsets of macrophages and osteoclasts that exists either as an enzymatically inactive monomer or as an active, proteolytically processed dimer.Using mice over expressing TRAP, we show that over-expression of monomeric, but not the dimeric form in adipose tissue leads to early onset spontaneous hyperplastic obesity i.e. many small fat cells. In vitro, recombinant monomeric, but not proteolytically processed TRAP induced proliferation and differentiation of mouse and human adipocyte precursor cells. In humans, monomeric TRAP was highly expressed in the adipose tissue of obese individuals. In both the mouse model and in the obese humans the source of TRAP in adipose tissue was macrophages. In addition, the obese TRAP over expressing mice exhibited signs of a low-grade inflammatory reaction in adipose tissue without evidence of abnormal adipocyte lipolysis, lipogenesis or insulin sensitivity.Monomeric TRAP, most likely secreted from adipose tissue macrophages, induces hyperplastic obesity with normal adipocyte lipid metabolism and insulin sensitivity.

  13. The RhoGAP Stard13 controls insulin secretion through F-actin remodeling

    Directory of Open Access Journals (Sweden)

    Heike Naumann

    2018-02-01

    Full Text Available Objective: Actin cytoskeleton remodeling is necessary for glucose-stimulated insulin secretion in pancreatic β-cells. A mechanistic understanding of actin dynamics in the islet is paramount to a better comprehension of β-cell dysfunction in diabetes. Here, we investigate the Rho GTPase regulator Stard13 and its role in F-actin cytoskeleton organization and islet function in adult mice. Methods: We used Lifeact-EGFP transgenic animals to visualize actin cytoskeleton organization and dynamics in vivo in the mouse islets. Furthermore, we applied this model to study actin cytoskeleton and insulin secretion in mutant mice deleted for Stard13 selectively in pancreatic cells. We isolated transgenic islets for 3D-imaging and perifusion studies to measure insulin secretion dynamics. In parallel, we performed histological and morphometric analyses of the pancreas and used in vivo approaches to study glucose metabolism in the mouse. Results: In this study, we provide the first genetic evidence that Stard13 regulates insulin secretion in response to glucose. Postnatally, Stard13 expression became restricted to the mouse pancreatic islets. We showed that Stard13 deletion results in a marked increase in actin polymerization in islet cells, which is accompanied by severe reduction of insulin secretion in perifusion experiments. Consistently, Stard13-deleted mice displayed impaired glucose tolerance and reduced glucose-stimulated insulin secretion. Conclusions: Taken together, our results suggest a previously unappreciated role for the RhoGAP protein Stard13 in the interplay between actin cytoskeletal remodeling and insulin secretion. Keywords: F-actin, Insulin secretion, Islet, Pancreas, Lifeact, Stard13

  14. Stress-induced dissociations between intracellular calcium signaling and insulin secretion in pancreatic islets.

    Science.gov (United States)

    Qureshi, Farhan M; Dejene, Eden A; Corbin, Kathryn L; Nunemaker, Craig S

    2015-05-01

    In healthy pancreatic islets, glucose-stimulated changes in intracellular calcium ([Ca(2+)]i) provide a reasonable reflection of the patterns and relative amounts of insulin secretion. We report that [Ca(2+)]i in islets under stress, however, dissociates with insulin release in different ways for different stressors. Islets were exposed for 48h to a variety of stressors: cytokines (low-grade inflammation), 28mM glucose (28G, glucotoxicity), free fatty acids (FFAs, lipotoxicity), thapsigargin (ER stress), or rotenone (mitochondrial stress). We then measured [Ca(2+)]i and insulin release in parallel studies. Islets exposed to all stressors except rotenone displayed significantly elevated [Ca(2+)]i in low glucose, however, increased insulin secretion was only observed for 28G due to increased nifedipine-sensitive calcium-channel flux. Following 3-11mM glucose stimulation, all stressors substantially reduced the peak glucose-stimulated [Ca(2+)]i response (first phase). Thapsigargin and cytokines also substantially impacted aspects of calcium influx and ER calcium handling. Stressors did not significantly impact insulin secretion in 11mM glucose for any stressor, although FFAs showed a borderline reduction, which contributed to a significant decrease in the stimulation index (11:3mM glucose) observed for FFAs and also for 28G. We also clamped [Ca(2+)]i using 30mM KCl+250μM diazoxide to test the amplifying pathway. Only rotenone-treated islets showed a robust increase in 3-11mM glucose-stimulated insulin secretion under clamped conditions, suggesting that low-level mitochondrial stress might activate the metabolic amplifying pathway. We conclude that different stressors dissociate [Ca(2+)]i from insulin secretion differently: ER stressors (thapsigargin, cytokines) primarily affect [Ca(2+)]i but not conventional insulin secretion and 'metabolic' stressors (FFAs, 28G, rotenone) impacted insulin secretion. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Tau hyperphosphorylation induces oligomeric insulin accumulation and insulin resistance in neurons.

    Science.gov (United States)

    Rodriguez-Rodriguez, Patricia; Sandebring-Matton, Anna; Merino-Serrais, Paula; Parrado-Fernandez, Cristina; Rabano, Alberto; Winblad, Bengt; Ávila, Jesús; Ferrer, Isidre; Cedazo-Minguez, Angel

    2017-12-01

    Insulin signalling deficiencies and insulin resistance have been directly linked to the progression of neurodegenerative disorders like Alzheimer's disease. However, to date little is known about the underlying molecular mechanisms or insulin state and distribution in the brain under pathological conditions. Here, we report that insulin is accumulated and retained as oligomers in hyperphosphorylated tau-bearing neurons in Alzheimer's disease and in several of the most prevalent human tauopathies. The intraneuronal accumulation of insulin is directly dependent on tau hyperphosphorylation, and follows the tauopathy progression. Furthermore, cells accumulating insulin show signs of insulin resistance and decreased insulin receptor levels. These results suggest that insulin retention in hyperphosphorylated tau-bearing neurons is a causative factor for the insulin resistance observed in tauopathies, and describe a novel neuropathological concept with important therapeutic implications. © The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Blueberries? Impact on Insulin Resistance and Glucose Intolerance

    OpenAIRE

    Stull, April J.

    2016-01-01

    Blueberries are a rich source of polyphenols, which include anthocyanin bioactive compounds. Epidemiological evidence indicates that incorporating blueberries into the diet may lower the risk of developing type 2 diabetes (T2DM). These findings are supported by pre-clinical and clinical studies that have shown improvements in insulin resistance (i.e., increased insulin sensitivity) after obese and insulin-resistant rodents or humans consumed blueberries. Insulin resistance was assessed by hom...

  17. Insulin resistance and polycystic ovary syndrome.

    Science.gov (United States)

    Galluzzo, Aldo; Amato, Marco Calogero; Giordano, Carla

    2008-09-01

    Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in humans, affecting approximately 7-8% of women of reproductive age. Despite the criteria adopted, PCOS is considered to be a predominantly hyperandrogenetic syndrome and the evaluation of metabolic parameters and insulin sensitivity is not mandatory. Most women with PCOS also exhibit features of the metabolic syndrome, including insulin resistance, obesity and dyslipidaemia. While the association with type 2 diabetes is well established, whether the incidence of cardiovascular disease is increased in women with PCOS remains unclear. Acknowledging the strong impact of insulin-resistance in the genesis of PCOS could be helpful not only to make the diagnosis more robust, but also for conferring better cardiovascular risk prevention. Several current studies support a strong recommendation that women with PCOS should undergo comprehensive evaluation for the metabolic syndrome and recognized cardiovascular risk factors, and receive appropriate treatment as needed. Lifestyle modifications remain the first-line therapy for all obese women with PCOS. However, many of these women do not lose weight easily. Insulin-sensitizing drugs are discussed as a promising and unique therapeutic option for the chronic treatment of PCOS.

  18. Mitochondrial metabolism of pyruvate is essential for regulating glucose-stimulated insulin secretion.

    Science.gov (United States)

    Patterson, Jessica N; Cousteils, Katelyn; Lou, Jennifer W; Manning Fox, Jocelyn E; MacDonald, Patrick E; Joseph, Jamie W

    2014-05-09

    It is well known that mitochondrial metabolism of pyruvate is critical for insulin secretion; however, we know little about how pyruvate is transported into mitochondria in β-cells. Part of the reason for this lack of knowledge is that the carrier gene was only discovered in 2012. In the current study, we assess the role of the recently identified carrier in the regulation of insulin secretion. Our studies show that β-cells express both mitochondrial pyruvate carriers (Mpc1 and Mpc2). Using both pharmacological inhibitors and siRNA-mediated knockdown of the MPCs we show that this carrier plays a key role in regulating insulin secretion in clonal 832/13 β-cells as well as rat and human islets. We also show that the MPC is an essential regulator of both the ATP-regulated potassium (KATP) channel-dependent and -independent pathways of insulin secretion. Inhibition of the MPC blocks the glucose-stimulated increase in two key signaling molecules involved in regulating insulin secretion, the ATP/ADP ratio and NADPH/NADP(+) ratio. The MPC also plays a role in in vivo glucose homeostasis as inhibition of MPC by the pharmacological inhibitor α-cyano-β-(1-phenylindol-3-yl)-acrylate (UK5099) resulted in impaired glucose tolerance. These studies clearly show that the newly identified mitochondrial pyruvate carrier sits at an important branching point in nutrient metabolism and that it is an essential regulator of insulin secretion.

  19. Macrophage mTORC1 disruption reduces inflammation and insulin resistance in obese mice

    NARCIS (Netherlands)

    Jiang, Hongfeng; Westerterp, Marit; Wang, Chunjiong; Zhu, Yi; Ai, Ding

    2014-01-01

    Inflammatory factors secreted by macrophages play an important role in obesity-related insulin resistance. Being at the crossroads of a nutrient-hormonal signalling network, the mammalian target of rapamycin complex 1 (mTORC1) controls important functions in the regulation of energy balance and

  20. Sirt1 regulates insulin secretion by repressing UCP2 in pancreatic beta cells.

    Directory of Open Access Journals (Sweden)

    Laura Bordone

    2006-02-01

    Full Text Available Sir2 and insulin/IGF-1 are the major pathways that impinge upon aging in lower organisms. In Caenorhabditis elegans a possible genetic link between Sir2 and the insulin/IGF-1 pathway has been reported. Here we investigate such a link in mammals. We show that Sirt1 positively regulates insulin secretion in pancreatic beta cells. Sirt1 represses the uncoupling protein (UCP gene UCP2 by binding directly to the UCP2 promoter. In beta cell lines in which Sirt1 is reduced by SiRNA, UCP2 levels are elevated and insulin secretion is blunted. The up-regulation of UCP2 is associated with a failure of cells to increase ATP levels after glucose stimulation. Knockdown of UCP2 restores the ability to secrete insulin in cells with reduced Sirt1, showing that UCP2 causes the defect in glucose-stimulated insulin secretion. Food deprivation induces UCP2 in mouse pancreas, which may occur via a reduction in NAD (a derivative of niacin levels in the pancreas and down-regulation of Sirt1. Sirt1 knockout mice display constitutively high UCP2 expression. Our findings show that Sirt1 regulates UCP2 in beta cells to affect insulin secretion.

  1. Intracellular and extracellular adenosine triphosphate in regulation of insulin secretion from pancreatic β cells (β).

    Science.gov (United States)

    Wang, Chunjiong; Geng, Bin; Cui, Qinghua; Guan, Youfei; Yang, Jichun

    2014-03-01

    Adenosine triphosphate (ATP) synthesis and release in mitochondria play critical roles in regulating insulin secretion in pancreatic β cells. Mitochondrial dysfunction is mainly characterized by a decrease in ATP production, which is a central event in the progression of pancreatic β cell dysfunction and diabetes. ATP has been demonstrated to regulate insulin secretion via several pathways: (i) Intracellular ATP directly closes ATP-sensitive potassium channel to open L-type calcium channel, leading to an increase in free cytosolic calcium levels and exocytosis of insulin granules; (ii) A decrease in ATP production is always associated with an increase in production of reactive oxygen species, which exerts deleterious effects on pancreatic β cell survival and insulin secretion; and (iii) ATP can be co-secreted with insulin from pancreatic β cells, and the released ATP functions as an autocrine signal to modulate insulin secretory process via P2 receptors on the cell membrane. In this review, the recent findings regarding the role and mechanism of ATP synthesis and release in regulation of insulin secretion from pancreatic β cells will be summarized and discussed. © 2013 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and Wiley Publishing Asia Pty Ltd.

  2. Decrement of postprandial insulin secretion determines the progressive nature of type-2 diabetes.

    Science.gov (United States)

    Shim, Wan Sub; Kim, Soo Kyung; Kim, Hae Jin; Kang, Eun Seok; Ahn, Chul Woo; Lim, Sung Kil; Lee, Hyun Chul; Cha, Bong Soo

    2006-10-01

    Type-2 diabetes is a progressive disease. However, little is known about whether decreased fasting or postprandial pancreatic beta-cell responsiveness is more prominent with increased duration of diabetes. The aim of this study was to evaluate the relationship between insulin secretion both during fasting and 2 h postprandial, and the duration of diabetes in type-2 diabetic patients. Cross-sectional clinical investigation. We conducted a meal tolerance test in 1466 type-2 diabetic patients and calculated fasting (M0) and postprandial (M1) beta-cell responsiveness. The fasting C-peptide, postprandial C-peptide, M0, and M1 values were lower, but HbA1c values were higher, in patients with diabetes duration > 10 years than those in other groups. There was no difference in the HbA1c levels according to the tertiles of their fasting C-peptide level. However, in a group of patients with highest postprandial C-peptide tertile, the HbA1c values were significantly lower than those in other groups. After adjustment of age, sex, and body mass index (BMI), the duration of diabetes was found to be negatively correlated with fasting C-peptide (gamma = -0.102), postprandial C-peptide (gamma = -0.356), M0 (gamma = -0.263), and M1 (gamma = -0.315; P multiple regression analysis, M0, M1, and homeostasis model assessment for insulin resistance (HOMA-IR) emerged as predictors of HbAlc after adjustment for age, sex, and BMI (R2 = 0.272, 0.080, and 0.056 respectively). With increasing duration of diabetes, the decrease of postprandial insulin secretion is becoming more prominent, and postprandial beta-cell responsiveness may be a more important determinant for glycemic control than fasting beta-cell responsiveness.

  3. Biochemical adaptations of mammalian hibernation: exploring squirrels as a perspective model for naturally induced reversible insulin resistance

    Energy Technology Data Exchange (ETDEWEB)

    Wu, C-W.; Biggar, K.K.; Storey, K.B. [Carleton University, Department of Biology, Institute of Biochemistry, Ottawa, ON (Canada)

    2013-01-28

    An important disease among human metabolic disorders is type 2 diabetes mellitus. This disorder involves multiple physiological defects that result from high blood glucose content and eventually lead to the onset of insulin resistance. The combination of insulin resistance, increased glucose production, and decreased insulin secretion creates a diabetic metabolic environment that leads to a lifetime of management. Appropriate models are critical for the success of research. As such, a unique model providing insight into the mechanisms of reversible insulin resistance is mammalian hibernation. Hibernators, such as ground squirrels and bats, are excellent examples of animals exhibiting reversible insulin resistance, for which a rapid increase in body weight is required prior to entry into dormancy. Hibernator studies have shown differential regulation of specific molecular pathways involved in reversible resistance to insulin. The present review focuses on this growing area of research and the molecular mechanisms that regulate glucose homeostasis, and explores the roles of the Akt signaling pathway during hibernation. Here, we propose a link between hibernation, a well-documented response to periods of environmental stress, and reversible insulin resistance, potentially facilitated by key alterations in the Akt signaling network, PPAR-γ/PGC-1α regulation, and non-coding RNA expression. Coincidentally, many of the same pathways are frequently found to be dysregulated during insulin resistance in human type 2 diabetes. Hence, the molecular networks that may regulate reversible insulin resistance in hibernating mammals represent a novel approach by providing insight into medical treatment of insulin resistance in humans.

  4. Biochemical adaptations of mammalian hibernation: exploring squirrels as a perspective model for naturally induced reversible insulin resistance

    International Nuclear Information System (INIS)

    Wu, C-W.; Biggar, K.K.; Storey, K.B.

    2013-01-01

    An important disease among human metabolic disorders is type 2 diabetes mellitus. This disorder involves multiple physiological defects that result from high blood glucose content and eventually lead to the onset of insulin resistance. The combination of insulin resistance, increased glucose production, and decreased insulin secretion creates a diabetic metabolic environment that leads to a lifetime of management. Appropriate models are critical for the success of research. As such, a unique model providing insight into the mechanisms of reversible insulin resistance is mammalian hibernation. Hibernators, such as ground squirrels and bats, are excellent examples of animals exhibiting reversible insulin resistance, for which a rapid increase in body weight is required prior to entry into dormancy. Hibernator studies have shown differential regulation of specific molecular pathways involved in reversible resistance to insulin. The present review focuses on this growing area of research and the molecular mechanisms that regulate glucose homeostasis, and explores the roles of the Akt signaling pathway during hibernation. Here, we propose a link between hibernation, a well-documented response to periods of environmental stress, and reversible insulin resistance, potentially facilitated by key alterations in the Akt signaling network, PPAR-γ/PGC-1α regulation, and non-coding RNA expression. Coincidentally, many of the same pathways are frequently found to be dysregulated during insulin resistance in human type 2 diabetes. Hence, the molecular networks that may regulate reversible insulin resistance in hibernating mammals represent a novel approach by providing insight into medical treatment of insulin resistance in humans

  5. Circadian control of insulin secretion is independent of the temporal distribution of feeding

    NARCIS (Netherlands)

    Kalsbeek, Andries; Strubbe, JH

    1998-01-01

    To investigate whether there is a circadian regulation of insulin secretion, rats were adapted to a feeding regimen of six meals equally distributed over 24 h. Under these conditions basal glucose and insulin levels increased during the light phase and decreased during the dark phase. Maximal blood

  6. Insulin induces a shift in lipid and primary carbon metabolites in a model of fasting-induced insulin resistance

    Science.gov (United States)

    Olmstead, Keedrian I.; La Frano, Michael R.; Fahrmann, Johannes; Grapov, Dmitry; Viscarra, Jose A.; Newman, John W.; Fiehn, Oliver; Crocker, Daniel E.; Filipp, Fabian V.; Ortiz, Rudy M.

    2017-01-01

    Introduction Prolonged fasting in northern elephant seals (NES) is characterized by a reliance on lipid metabolism, conservation of protein, and reduced plasma insulin. During early fasting, glucose infusion previously reduced plasma free fatty acids (FFA); however, during late-fasting, it induced an atypical elevation in FFA despite comparable increases in insulin during both periods suggestive of a dynamic shift in tissue responsiveness to glucose-stimulated insulin secretion. Objective To better assess the contribution of insulin to this fasting-associated shift in substrate metabolism. Methods We compared the responses of plasma metabolites (amino acids (AA), FFA, endocannabinoids (EC), and primary carbon metabolites (PCM)) to an insulin infusion (65 mU/kg) in early- and late-fasted NES pups (n = 5/group). Plasma samples were collected prior to infusion (T0) and at 10, 30, 60, and 120 min post-infusion, and underwent untargeted and targeted metabolomics analyses utilizing a variety of GC-MS and LC-MS technologies. Results In early fasting, the majority (72%) of metabolite trajectories return to baseline levels within 2 h, but not in late fasting indicative of an increase in tissue sensitivity to insulin. In late-fasting, increases in FFA and ketone pools, coupled with decreases in AA and PCM, indicate a shift toward lipolysis, beta-oxidation, ketone metabolism, and decreased protein catabolism. Conversely, insulin increased PCM AUC in late fasting suggesting that gluconeogenic pathways are activated. Insulin also decreased FFA AUC between early and late fasting suggesting that insulin suppresses triglyceride hydrolysis. Conclusion Naturally adapted tolerance to prolonged fasting in these mammals is likely accomplished by suppressing insulin levels and activity, providing novel insight on the evolution of insulin during a condition of temporary, reversible insulin resistance. PMID:28757815

  7. Insulin resistance in polycystic ovary syndrome

    OpenAIRE

    Hutchison, Samantha Kate

    2017-01-01

    Polycystic ovary syndrome (PCOS) affects 8-18% of women, presenting a major public health and economic burden. Women with PCOS have insulin resistance (IR) independent of obesity. IR has an integral aetiological role in the reproductive and metabolic consequences of PCOS including obesity, type 2 diabetes (diabetes) and cardiovascular risk factors. Excess weight exacerbates IR and increases PCOS severity. PCOS combined with obesity presents a useful model to study IR before confounding hyperg...

  8. Mitochondrial adaptations in insulin resistant muscle

    OpenAIRE

    Broek, van den, N.M.A.

    2010-01-01

    Diabetes has reached epidemic proportions worldwide. Type 2 diabetes (T2D) accounts for about 90% of all diabetes cases and is characterized by insulin resistance (IR) in major metabolic tissues. The dramatic rise in T2D is associated with the increased occurrence of obesity and excessive ectopic lipid accumulation, in particular in skeletal muscle, due to excessive caloric intake and decreased physical activity. However, the exact processes leading to IR remain unresolved. One of the leading...

  9. [Insulin resistance--a physiopathological condition with numerous sequelae: non-insulin-dependent diabetes mellitus (NIDDM), android obesity, essential hypertension, dyslipidemia and atherosclerosis].

    Science.gov (United States)

    Pedersen, O

    1992-05-11

    Recent research has demonstrated that reduced insulin-stimulated glucose metabolism in skeletal muscle (insulin resistance) and hyperinsulinism are common features in widespread diseases such as essential hypertension, android obesity, non-insulin dependent diabetes mellitus, dyslipidemia (in the form of raised serum triglyceride and reduced serum high-density lipoprotein (HDL) cholesterol) and arteriosclerosis. Simultaneously, investigations in a comprehensive group of healthy middle-aged men have revealed insulin resistance in one fourth. On the basis of these observations, a working hypothesis is suggested which postulates that genetic abnormalities in one or more of the candidate genes in the modes of action of insulin occur in a great proportion of the population. These may result in insulin resistance (primary genetic insulin resistance). Primary insulin resistance may be potentiated by a series of circumstances such as ageing, high-fat diet, lack of physical activity, hormonal and metabolic abnormalities or drugs (secondary insulin resistance). As a consequence of the reduced effect of insulin on muscle tissue, compensatory hyperinsulinism develops. Depending on the remaining vulnerability of the individual the hyperinsulinism is presumed to result in development of one or more phenotypes. For example if the beta-cells of the pancreas are unable to secrete sufficient insulin to compensate the insulin resistance on account of genetic defects, glucose intolerance will develop. In a similar manner, hyperinsulinism in insulin-resistant individuals who are predisposed to essential hypertension is presumed to reveal genetic defects in the blood pressure regulating mechanisms and thus contribute to development of the disease.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. IRS-1 serine phosphorylation and insulin resistance in skeletal muscle from pancreas tranplant recipient

    DEFF Research Database (Denmark)

    Bouzakri, K; Karlsson, HRK; Vestergaard, Henrik

    2006-01-01

    Insulin-dependent diabetic recipients of successful pancreas allografts achieve self-regulatory insulin secretion and discontinue exogenous insulin therapy; however, chronic hyperinsulinemia and impaired insulin sensitivity generally develop. To determine whether insulin resistance is accompanied...... by altered signal transduction, skeletal muscle biopsies were obtained from pancreas-kidney transplant recipients (n = 4), nondiabetic kidney transplant recipients (receiving the same immunosuppressive drugs; n = 5), and healthy subjects (n = 6) before and during a euglycemic-hyperinsulinemic clamp. Basal...... insulin receptor substrate (IRS)-1 Ser (312) and Ser (616) phosphorylation, IRS-1-associated phosphatidylinositol 3-kinase activity, and extracellular signal-regulated kinase (ERK)-1/2 phosphorylation were elevated in pancreas-kidney transplant recipients, coincident with fasting hyperinsulinemia. Basal...

  11. IRS-1 serine phosphorylation and insulin resistance in skeletal muscle from pancreas transplant recipients

    DEFF Research Database (Denmark)

    Bouzakri, Karim; Karlsson, Håkan K R; Vestergaard, Henrik

    2006-01-01

    Insulin-dependent diabetic recipients of successful pancreas allografts achieve self-regulatory insulin secretion and discontinue exogenous insulin therapy; however, chronic hyperinsulinemia and impaired insulin sensitivity generally develop. To determine whether insulin resistance is accompanied...... by altered signal transduction, skeletal muscle biopsies were obtained from pancreas-kidney transplant recipients (n = 4), nondiabetic kidney transplant recipients (receiving the same immunosuppressive drugs; n = 5), and healthy subjects (n = 6) before and during a euglycemic-hyperinsulinemic clamp. Basal...... insulin receptor substrate (IRS)-1 Ser (312) and Ser (616) phosphorylation, IRS-1-associated phosphatidylinositol 3-kinase activity, and extracellular signal-regulated kinase (ERK)-1/2 phosphorylation were elevated in pancreas-kidney transplant recipients, coincident with fasting hyperinsulinemia. Basal...

  12. Molecular Mechanisms of Insulin Resistance in Chronic Kidney Disease

    Science.gov (United States)

    Thomas, Sandhya S.; Zhang, Liping; Mitch, William E.

    2015-01-01

    Insulin resistance refers to reduced sensitivity of organs to insulin-initiated biologic processes that result in metabolic defects. Insulin resistance is common in patients with end-stage renal disease but also occurs in patients with chronic kidney disease (CKD), even when the serum creatinine is minimally increased. Following insulin binding to its receptor, auto-phosphorylation of the insulin receptor is followed by kinase reactions that phosphorylate insulin receptor substrate-1 (IRS-1), phosphatidylinositol 3-kinase (PI3K) and Akt. In fact, low levels of Akt phosphorylation (p-Akt) identifies the presence of the insulin resistance that leads to metabolic defects in insulin-initiated metabolism of glucose, lipids and muscle proteins. Besides CKD, other complex conditions (e.g., inflammation, oxidative stress, metabolic acidosis, aging and excess angiotensin II) reduce p-Akt resulting in insulin resistance. Insulin resistance in each of these conditions is due to activation of different, E3 ubiquitin ligases which specifically conjugate ubiquitin to IRS-1 marking it for degradation in the ubiquitin-proteasome system (UPS). Consequently, IRS-1 degradation suppresses insulin-induced intracellular signaling, causing insulin resistance. Understanding mechanisms of insulin resistance could lead to therapeutic strategies that improve the metabolism of patients with CKD. PMID:26444029

  13. Insulin receptor internalization defect in an insulin-resistant mouse melanoma cell line

    International Nuclear Information System (INIS)

    Androlewicz, M.J.; Straus, D.S.; Brandenburg, D.F.

    1989-01-01

    Previous studies from this laboratory demonstrated that the PG19 mouse melanoma cell line does not exhibit a biological response to insulin, whereas melanoma x mouse embryo fibroblast hybrids do respond to insulin. To investigate the molecular basis of the insulin resistance of the PG19 melanoma cells, insulin receptors from the insulin-resistant melanoma cells and insulin-sensitive fibroblast x melanoma hybrid cells were analyzed by the technique of photoaffinity labeling using the photoprobe 125 I-NAPA-DP-insulin. Photolabeled insulin receptors from the two cell types have identical molecular weights as determined by SDS gel electrophoresis under reducing and nonreducing conditions, indicating that the receptors on the two cell lines are structurally similar. Insulin receptor internalization studies revealed that the hybrid cells internalize receptors to a high degree at 37 degree C, whereas the melanoma cells internalize receptors to a very low degree or not at all. The correlation between ability to internalize insulin receptors and sensitivity to insulin action in this system suggests that uptake of the insulin-receptor complex may be required for insulin action in these cells. Insulin receptors from the two cell lines autophosphorylate in a similar insulin-dependent manner both in vitro and in intact cells, indicating that insulin receptors on the melanoma and hybrid cells have functional tyrosine protein kinase activity. Therefore, the block in insulin action in the PG19 melanoma cells appears to reside at a step beyond insulin-stimulated receptor autophosphorylation

  14. Insulin Resistance Induced by Short term Fructose Feeding may not ...

    African Journals Online (AJOL)

    Fructose feeding causes insulin resistance and invariably Non-Insulin Dependent Diabetes Mellitus (NIDDM) in rats and genetically predisposed humans. The effect of insulin resistance induced by short term fructose feeding on fertility in female rats was investigated using the following parameters: oestrous phase and ...

  15. Natural history of insulin sensitivity and insulin secretion in the progression from normal glucose tolerance to impaired fasting glycemia and impaired glucose tolerance: the Inter99 study

    DEFF Research Database (Denmark)

    Faerch, Kristine; Vaag, Allan; Holst, Jens J

    2008-01-01

    of insulin sensitivity (HOMA-IS), early-phase insulin release (EPIR), and insulin secretion relative to insulin action (disposition index) were estimated. RESULTS: Five years before the pre-diabetes diagnoses (i-IFG, i-IGT, and IFG/IGT), ISI, HOMA-IS, EPIR, and disposition index were lower than...

  16. Insulin resistance in obesity can be reliably identified from fasting plasma insulin.

    Science.gov (United States)

    ter Horst, K W; Gilijamse, P W; Koopman, K E; de Weijer, B A; Brands, M; Kootte, R S; Romijn, J A; Ackermans, M T; Nieuwdorp, M; Soeters, M R; Serlie, M J

    2015-12-01

    Insulin resistance is the major contributor to cardiometabolic complications of obesity. We aimed to (1) establish cutoff points for insulin resistance from euglycemic hyperinsulinemic clamps (EHCs), (2) identify insulin-resistant obese subjects and (3) predict insulin resistance from routinely measured variables. We assembled data from non-obese (n=112) and obese (n=100) men who underwent two-step EHCs using [6,6-(2)H2]glucose as tracer (insulin infusion dose 20 and 60 mU m(-2) min(-1), respectively). Reference ranges for hepatic and peripheral insulin sensitivity were calculated from healthy non-obese men. Based on these reference values, obese men with preserved insulin sensitivity or insulin resistance were identified. Cutoff points for insulin-mediated suppression of endogenous glucose production (EGP) and insulin-stimulated glucose disappearance rate (Rd) were 46.5% and 37.3 μmol kg(-)(1) min(-)(1), respectively. Most obese men (78%) had EGP suppression within the reference range, whereas only 12% of obese men had Rd within the reference range. Obese men with Rd obese men in age, body mass index (BMI), body composition, fasting glucose or cholesterol, but did have higher fasting insulin (110±49 vs 63±29 pmol l(-1), Pobese men could be identified with good sensitivity (80%) and specificity (75%) from fasting insulin >74 pmol l(-1). Most obese men have hepatic insulin sensitivity within the range of non-obese controls, but below-normal peripheral insulin sensitivity, that is, insulin resistance. Fasting insulin (>74 pmol l(-1) with current insulin immunoassay) may be used for identification of insulin-resistant (or metabolically unhealthy) obese men in research and clinical settings.

  17. Beta-cell function is associated with carotid intima-media thickness independently of insulin resistance in healthy individuals

    DEFF Research Database (Denmark)

    Roussel, Ronan; Natali, Andrea; Balkau, Beverley

    2016-01-01

    Objective: It is a common belief that early atherosclerosis in prediabetes is causally linked to endothelial insulin resistance. Another condition, a low insulin secretion, may be associated with insufficient insulin action on the vascular wall and consequently favor atherosclerosis. Our aim...... was to test this hypothesis in people without diabetes, taking into account the gold-standard measurement of insulin sensitivity, a major confounder in the relationship between insulin secretion and atherosclerosis. Methods: We studied the European Relationship between Insulin Sensitivity and Cardiovascular...... Risk cohort of 451 men and 593 women (44±8 years, mean±SD) who were free of diabetes, hypertension, dyslipidemia, and other known chronic or acute conditions. All underwent an oral glucose tolerance test, a euglycemic-hyperinsulinemic clamp (M/I measured insulin sensitivity), and B-mode carotid...

  18. PEDF-induced alteration of metabolism leading to insulin resistance.

    Science.gov (United States)

    Carnagarin, Revathy; Dharmarajan, Arunasalam M; Dass, Crispin R

    2015-02-05

    Pigment epithelium-derived factor (PEDF) is an anti-angiogenic, immunomodulatory, and neurotrophic serine protease inhibitor protein. PEDF is evolving as a novel metabolic regulatory protein that plays a causal role in insulin resistance. Insulin resistance is the central pathogenesis of metabolic disorders such as obesity, type 2 diabetes mellitus, polycystic ovarian disease, and metabolic syndrome, and PEDF is associated with them. The current evidence suggests that PEDF administration to animals induces insulin resistance, whereas neutralisation improves insulin sensitivity. Inflammation, lipolytic free fatty acid mobilisation, and mitochondrial dysfunction are the proposed mechanism of PEDF-mediated insulin resistance. This review summarises the probable mechanisms adopted by PEDF to induce insulin resistance, and identifies PEDF as a potential therapeutic target in ameliorating insulin resistance. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  19. Exposures to arsenite and methylarsonite produce insulin resistance and impair insulin-dependent glycogen metabolism in hepatocytes.

    Science.gov (United States)

    Zhang, Chongben; Fennel, Emily M J; Douillet, Christelle; Stýblo, Miroslav

    2017-12-01

    Environmental exposure to inorganic arsenic (iAs) has been shown to disturb glucose homeostasis, leading to diabetes. Previous laboratory studies have suggested several mechanisms that may underlie the diabetogenic effects of iAs exposure, including (i) inhibition of insulin signaling (leading to insulin resistance) in glucose metabolizing peripheral tissues, (ii) inhibition of insulin secretion by pancreatic β cells, and (iii) dysregulation of the methylation or expression of genes involved in maintenance of glucose or insulin metabolism and function. Published studies have also shown that acute or chronic iAs exposures may result in depletion of hepatic glycogen stores. However, effects of iAs on pathways and mechanisms that regulate glycogen metabolism in the liver have never been studied. The present study examined glycogen metabolism in primary murine hepatocytes exposed in vitro to arsenite (iAs 3+ ) or its methylated metabolite, methylarsonite (MAs 3+ ). The results show that 4-h exposures to iAs 3+ and MAs 3+ at concentrations as low as 0.5 and 0.2 µM, respectively, decreased glycogen content in insulin-stimulated hepatocytes by inhibiting insulin-dependent activation of glycogen synthase (GS) and by inducing activity of glycogen phosphorylase (GP). Further investigation revealed that both iAs 3+ and MAs 3+ inhibit insulin-dependent phosphorylation of protein kinase B/Akt, one of the mechanisms involved in the regulation of GS and GP by insulin. Thus, inhibition of insulin signaling (i.e., insulin resistance) is likely responsible for the dysregulation of glycogen metabolism in hepatocytes exposed to iAs 3+ and MAs 3+ . This study provides novel information about the mechanisms by which iAs exposure impairs glucose homeostasis, pointing to hepatic metabolism of glycogen as one of the targets.

  20. Insulin sensitivity and metabolic flexibility following exercise training among different obese insulin resistant phenotypes

    DEFF Research Database (Denmark)

    Malin, Steven K; Haus, Jacob M; Solomon, Thomas

    2013-01-01

    Impaired fasting glucose (IFG) blunts the reversal of impaired glucose tolerance (IGT) after exercise training. Metabolic inflexibility has been implicated in the etiology of insulin resistance, however, the efficacy of exercise on peripheral and hepatic insulin sensitivity or substrate utilizati...

  1. Tau deletion promotes brain insulin resistance.

    Science.gov (United States)

    Marciniak, Elodie; Leboucher, Antoine; Caron, Emilie; Ahmed, Tariq; Tailleux, Anne; Dumont, Julie; Issad, Tarik; Gerhardt, Ellen; Pagesy, Patrick; Vileno, Margaux; Bournonville, Clément; Hamdane, Malika; Bantubungi, Kadiombo; Lancel, Steve; Demeyer, Dominique; Eddarkaoui, Sabiha; Vallez, Emmanuelle; Vieau, Didier; Humez, Sandrine; Faivre, Emilie; Grenier-Boley, Benjamin; Outeiro, Tiago F; Staels, Bart; Amouyel, Philippe; Balschun, Detlef; Buee, Luc; Blum, David

    2017-08-07

    The molecular pathways underlying tau pathology-induced synaptic/cognitive deficits and neurodegeneration are poorly understood. One prevalent hypothesis is that hyperphosphorylation, misfolding, and fibrillization of tau impair synaptic plasticity and cause degeneration. However, tau pathology may also result in the loss of specific physiological tau functions, which are largely unknown but could contribute to neuronal dysfunction. In the present study, we uncovered a novel function of tau in its ability to regulate brain insulin signaling. We found that tau deletion leads to an impaired hippocampal response to insulin, caused by altered IRS-1 and PTEN (phosphatase and tensin homologue on chromosome 10) activities. Our data also demonstrate that tau knockout mice exhibit an impaired hypothalamic anorexigenic effect of insulin that is associated with energy metabolism alterations. Consistently, we found that tau haplotypes are associated with glycemic traits in humans. The present data have far-reaching clinical implications and raise the hypothesis that pathophysiological tau loss-of-function favors brain insulin resistance, which is instrumental for cognitive and metabolic impairments in Alzheimer's disease patients. © 2017 Marciniak et al.

  2. Adiponectin and waist circumference as predictors of insulin-resistance in women.

    Science.gov (United States)

    Bonneau, Graciela A; Pedrozo, Williams R; Berg, Gabriela

    2014-01-01

    The initial disturbance of insulin resistance seems to focus on adipose tissue is a dynamic organ involved in many physiological and metabolic processes. Expresses and secretes a variety of active peptides, adipocytokines. To evaluate the prevalence of insulin-resistance in an healthy urban middle age population and to explore the role of adiponectin, inflammatory biomarkers (hs-CRP) and traditional cardiovascular risk factors as predictors of the insulin-resistance state. We studied of 176 participants (117 women and 59 men, 25-74 years), individuals with diabetes, hypothyroidism or hyperthyroidism, infectious disease, renal, or hepatic neoplasms and pregnant women were excluded. We evaluated glucose, insulin, adiponectin and hs-CRP. We found that 17.2% of individuals presented insulin-resistance. Correlation was found between waist circumference, body mass index, blood pressure and HOMA index (pinsulin-resistance (pinsulin-resistance in men. Besides, postmenopausal women presented higher adiponectin levels than premenopausal 7.63 (4.46-9.58) vs 5.50 (3.83-7.40) μg/ml, p=0.01. Adiponectin and waist circumference are important predictors of insulin-resistance even in healthy non-diabetic women, they may open a new opportunity to improve current risk estimation. Copyright © 2013 Diabetes India. Published by Elsevier Ltd. All rights reserved.

  3. Fetal adaptations in insulin secretion result from high catecholamines during placental insufficiency.

    Science.gov (United States)

    Limesand, Sean W; Rozance, Paul J

    2017-08-01

    Placental insufficiency and intrauterine growth restriction (IUGR) of the fetus affects approximately 8% of all pregnancies and is associated with short- and long-term disturbances in metabolism. In pregnant sheep, experimental models with a small, defective placenta that restricts delivery of nutrients and oxygen to the fetus result in IUGR. Low blood oxygen concentrations increase fetal plasma catecholamine concentrations, which lower fetal insulin concentrations. All of these observations in sheep models with placental insufficiency are consistent with cases of human IUGR. We propose that sustained high catecholamine concentrations observed in the IUGR fetus produce developmental adaptations in pancreatic β-cells that impair fetal insulin secretion. Experimental evidence supporting this hypothesis shows that chronic elevation in circulating catecholamines in IUGR fetuses persistently inhibits insulin concentrations and secretion. Elevated catecholamines also allow for maintenance of a normal fetal basal metabolic rate despite low fetal insulin and glucose concentrations while suppressing fetal growth. Importantly, a compensatory augmentation in insulin secretion occurs following inhibition or cessation of catecholamine signalling in IUGR fetuses. This finding has been replicated in normally grown sheep fetuses following a 7-day noradrenaline (norepinephrine) infusion. Together, these programmed effects will potentially create an imbalance between insulin secretion and insulin-stimulated glucose utilization in the neonate which probably explains the transient hyperinsulinism and hypoglycaemia in some IUGR infants. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.

  4. Measuring phospholipase D activity in insulin-secreting pancreatic beta-cells and insulin-responsive muscle cells and adipocytes.

    Science.gov (United States)

    Cazzolli, Rosanna; Huang, Ping; Teng, Shuzhi; Hughes, William E

    2009-01-01

    Phospholipase D (PLD) is an enzyme producing phosphatidic acid and choline through hydrolysis of phosphatidylcholine. The enzyme has been identified as a member of a variety of signal transduction cascades and as a key regulator of numerous intracellular vesicle trafficking processes. A role for PLD in regulating glucose homeostasis is emerging as the enzyme has recently been identified in events regulating exocytosis of insulin from pancreatic beta-cells and also in insulin-stimulated glucose uptake through controlling GLUT4 vesicle exocytosis in muscle and adipose tissue. We present methodologies for assessing cellular PLD activity in secretagogue-stimulated insulin-secreting pancreatic beta-cells and also insulin-stimulated adipocyte and muscle cells, two of the principal insulin-responsive cell types controlling blood glucose levels.

  5. Radioimmunologic analysis of insulin secretion during acute radiation sickness

    Energy Technology Data Exchange (ETDEWEB)

    Barkalaya, A I

    1975-01-01

    Rats were subjected to whole-body gamma irradiation (750 rad) and the secretory activity of the insular apparatus was studied radioimmunologically, using insulin labelled with iodine-125. The post-radiation dynamics of the insulin concentration in the blood were shown to have a phase character. The insulin level had risen after 1, 3 and 8 days. After 2 days the hormone concentration had dropped significantly and become two times lower than normal. After the other time intervals, the concentration of insulin in the blood varied within normal limits.

  6. INSULIN AND INSULIN RESISTANCE: NEW MOLECULE MARKERS AND TARGET MOLECULE FOR THE DIAGNOSIS AND THERAPY OF DISEASES OF THE CENTRAL NERVOUS SYSTEM

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    A. B. Salmina

    2013-01-01

    Full Text Available The review summarizes current data on the role of insulin in the regulation of t glucose metabolism in the central nervous system at physiologic and pathologic conditions. For many years, the brain has been considered as an insulin-independent organ which utilizes glucose without insulin activity. However, it is become clear now that insulin not only regulates glucose transport and metabolism, but also has modulatory efftects in impact on excitability, proliferation and differentiation of brain progenitor cells, synaptic plasticity and memory formation, secretion of neurotransmitters, apoptosis. We have critically reviewed literature information and our own data on the role of insulin and insulin resistance in neuron-glia metabolic coupling, regulation of NAD+ metabolism and action of NAdependent enzymes, neurogenesis, brain development in (pathophysiological conditions. The paper clarifies interrelations between alterations in glucose homeostasis, development of insulin resistance and development of neurodegeneration (Alzheimer's disease and Parkinson's disease, autism, stroke, and depression. We discuss the application of novel molecular markers of insulin resistance (adipokines, α-hydroxybutyrate, BDNF, insulin-regulated aminopeptidase, provasopressin and molecular targets for diagnostics and treatment of brain disorders associated with insulin resistance.

  7. Insulin-stimulated glucose uptake in healthy and insulin-resistant skeletal muscle

    DEFF Research Database (Denmark)

    Deshmukh, Atul S

    2016-01-01

    transporter protein 4 (GLUT4) to the plasma membrane which leads to facilitated diffusion of glucose into the cell. Understanding the precise signaling events guiding insulin-stimulated glucose uptake is pivotal, because impairment in these signaling events leads to development of insulin resistance and type...... 2 diabetes. This review summarizes current understanding of insulin signaling pathways mediating glucose uptake in healthy and insulin-resistant skeletal muscle....

  8. The Relationship between 25-hydroxyvitamin D Levels, Insulin Sensitivity and Insulin Secretion in Women 3 Years after Delivery.

    Science.gov (United States)

    Tänczer, Tímea; Magenheim, Rita; Fürst, Ágnes; Domján, Beatrix; Janicsek, Zsófia; Szabó, Eszter; Ferencz, Viktória; Tabák, Ádám G

    2017-12-01

    There is a direct correlation between 25-hydroxyvitamin D (25[OH]D) levels and insulin sensitivity. Furthermore, women with gestational diabetes (GDM) may have lower levels of 25(OH)D compared to controls. The present study intended to investigate 25(OH)D levels and their association with insulin sensitivity and insulin secretion in women with prior GDM and in controls 3.2 years after delivery. A total of 87 patients with prior GDM and 45 randomly selected controls (age range, 22 to 44 years) with normal glucose tolerance during pregnancy nested within a cohort of all deliveries at Saint Margit Hospital, Budapest, between January 1 2005, and December 31 2006, were examined. Their 25(OH) D levels were measured by radioimmunoassay. Insulin sensitivity and fasting insulin secretion were estimated using the homeostasis model asssessment (HOMA) calculator and early insulin secretion by the insulinogenic index based on a 75 g oral glucose tolerance test. There was no significant difference in 25(OH)D levels between cases and controls (27.2±13.1 [±SD] vs. 26.9±9.8 ng/L). There was a positive association between HOMA insulin sensitivity and 25(OH)D levels (beta = 0.017; 95% CI 0.001 to 0.034/1 ng/mL) that was robust to adjustment for age and body mass index. There was a nonsignificant association between HOMA insulin secretion and 25(OH)D (p=0.099), while no association was found with the insulinogenic index. Prior GDM status was not associated with 25(OH)D levels; however, 25(OH) D levels were associated with HOMA insulin sensitivity. It is hypothesized that the association between HOMA insulin secretion and 25(OH)D levels is related to the autoregulation of fasting glucose levels because no association between 25(OH)D and insulinogenic index was found. Copyright © 2017 Diabetes Canada. Published by Elsevier Inc. All rights reserved.

  9. Sodium arsenite impairs insulin secretion and transcription in pancreatic β-cells

    International Nuclear Information System (INIS)

    Diaz-Villasenor, Andrea; Sanchez-Soto, M. Carmen; Cebrian, Mariano E.; Ostrosky-Wegman, Patricia; Hiriart, Marcia

    2006-01-01

    Human studies have shown that chronic inorganic arsenic (iAs) exposure is associated with a high prevalence and incidence of type 2 diabetes. However, the mechanism(s) underlying this effect are not well understood, and practically, there is no information available on the effects of arsenic on pancreatic β-cells functions. Thus, since insulin secreted by the pancreas plays a crucial role in maintaining glucose homeostasis, our aim was to determine if sodium arsenite impairs insulin secretion and mRNA expression in single adult rat pancreatic β-cells. Cells were treated with 0.5, 1, 2, 5 and 10 μM sodium arsenite and incubated for 72 and 144 h. The highest dose tested (10 μM) decreased β-cell viability, by 33% and 83%, respectively. Insulin secretion and mRNA expression were evaluated in the presence of 1 and 5 μM sodium arsenite. Basal insulin secretion, in 5.6 mM glucose, was not significantly affected by 1 or 5 μM treatment for 72 h, but basal secretion was reduced when cells were exposed to 5 μM sodium arsenite for 144 h. On the other hand, insulin secretion in response to 15.6 mM glucose decreased with sodium arsenite in a dose-dependent manner in such a way that cells were no longer able to distinguish between different glucose concentrations. We also showed a significant decrease in insulin mRNA expression of cells exposed to 5 μM sodium arsenite during 72 h. Our data suggest that arsenic may contribute to the development of diabetes mellitus by impairing pancreatic β-cell functions, particularly insulin synthesis and secretion

  10. Intracellular serotonin modulates insulin secretion from pancreatic beta-cells by protein serotonylation.

    Directory of Open Access Journals (Sweden)

    Nils Paulmann

    2009-10-01

    Full Text Available While serotonin (5-HT co-localization with insulin in granules of pancreatic beta-cells was demonstrated more than three decades ago, its physiological role in the etiology of diabetes is still unclear. We combined biochemical and electrophysiological analyses of mice selectively deficient in peripheral tryptophan hydroxylase (Tph1-/- and 5-HT to show that intracellular 5-HT regulates insulin secretion. We found that these mice are diabetic and have an impaired insulin secretion due to the lack of 5-HT in the pancreas. The pharmacological restoration of peripheral 5-HT levels rescued the impaired insulin secretion in vivo. These findings were further evidenced by patch clamp experiments with isolated Tph1-/- beta-cells, which clearly showed that the secretory defect is downstream of Ca(2+-signaling and can be rescued by direct intracellular application of 5-HT via the clamp pipette. In elucidating the underlying mechanism further, we demonstrate the covalent coupling of 5-HT by transglutaminases during insulin exocytosis to two key players in insulin secretion, the small GTPases Rab3a and Rab27a. This renders them constitutively active in a receptor-independent signaling mechanism we have recently termed serotonylation. Concordantly, an inhibition of such activating serotonylation in beta-cells abates insulin secretion. We also observed inactivation of serotonylated Rab3a by enhanced proteasomal degradation, which is in line with the inactivation of other serotonylated GTPases. Our results demonstrate that 5-HT regulates insulin secretion by serotonylation of GTPases within pancreatic beta-cells and suggest that intracellular 5-HT functions in various microenvironments via this mechanism in concert with the known receptor-mediated signaling.

  11. CNC-bZIP protein Nrf1-dependent regulation of glucose-stimulated insulin secretion.

    Science.gov (United States)

    Zheng, Hongzhi; Fu, Jingqi; Xue, Peng; Zhao, Rui; Dong, Jian; Liu, Dianxin; Yamamoto, Masayuki; Tong, Qingchun; Teng, Weiping; Qu, Weidong; Zhang, Qiang; Andersen, Melvin E; Pi, Jingbo

    2015-04-01

    The inability of pancreatic β-cells to secrete sufficient insulin in response to glucose stimulation is a major contributing factor to the development of type 2 diabetes (T2D). We investigated both the in vitro and in vivo effects of deficiency of nuclear factor-erythroid 2-related factor 1 (Nrf1) in β-cells on β-cell function and glucose homeostasis. Silencing of Nrf1 in β-cells leads to a pre-T2D phenotype with disrupted glucose metabolism and impaired insulin secretion. Specifically, MIN6 β-cells with stable knockdown of Nrf1 (Nrf1-KD) and isolated islets from β-cell-specific Nrf1-knockout [Nrf1(b)-KO] mice displayed impaired glucose responsiveness, including elevated basal insulin release and decreased glucose-stimulated insulin secretion (GSIS). Nrf1(b)-KO mice exhibited severe fasting hyperinsulinemia, reduced GSIS, and glucose intolerance. Silencing of Nrf1 in MIN6 cells resulted in oxidative stress and altered glucose metabolism, with increases in both glucose uptake and aerobic glycolysis, which is associated with the elevated basal insulin release and reduced glucose responsiveness. The elevated glycolysis and reduced glucose responsiveness due to Nrf1 silencing likely result from altered expression of glucose metabolic enzymes, with induction of high-affinity hexokinase 1 and suppression of low-affinity glucokinase. Our study demonstrated a novel role of Nrf1 in regulating glucose metabolism and insulin secretion in β-cells and characterized Nrf1 as a key transcription factor that regulates the coupling of glycolysis and mitochondrial metabolism and GSIS. Nrf1 plays critical roles in regulating glucose metabolism, mitochondrial function, and insulin secretion, suggesting that Nrf1 may be a novel target to improve the function of insulin-secreting β-cells.

  12. Effects of intranasal insulin on endogenous glucose production in insulin-resistant men.

    Science.gov (United States)

    Xiao, Changting; Dash, Satya; Stahel, Priska; Lewis, Gary F

    2018-03-14

    The effects of intranasal insulin on the regulation of endogenous glucose production (EGP) in individuals with insulin resistance were assessed in a single-blind, crossover study. Overweight or obese insulin-resistant men (n = 7; body mass index 35.4 ± 4.4 kg/m 2 , homeostatic model assessment of insulin resistance 5.6 ± 1.6) received intranasal spray of either 40 IU insulin lispro or placebo in 2 randomized visits. Acute systemic spillover of intranasal insulin into the circulation was matched with a 30-minute intravenous infusion of insulin lispro in the nasal placebo arm. EGP was assessed under conditions of a pancreatic clamp with a primed, constant infusion of glucose tracer. Under these experimental conditions, compared with placebo, intranasal administration of insulin did not significantly affect plasma glucose concentrations, EGP or glucose disposal in overweight/obese, insulin-resistant men, in contrast to our previous study, in which an equivalent dose of intranasal insulin significantly suppressed EGP in lean, insulin-sensitive men. Insulin resistance is probably associated with impairment in centrally mediated insulin suppression of EGP. © 2018 John Wiley & Sons Ltd.

  13. Evaluation of insulin expression and secretion in genetically engineered gut K and L-cells

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    Ahmad Zalinah

    2012-09-01

    Full Text Available Abstract Background Gene therapy could provide an effective treatment of diabetes. Previous studies have investigated the potential for several cell and tissue types to produce mature and active insulin. Gut K and L-cells could be potential candidate hosts for gene therapy because of their special features. Results In this study, we isolated gut K and L-cells to compare the potential of both cell types to produce insulin when exposed to similar conditions. The isolated pure K and L-cells were transfected with recombinant plasmids encoding insulin and with specific promoters for K or L-cells. Insulin expression was studied in response to glucose or meat hydrolysate. We found that glucose and meat hydrolysate efficiently induced insulin secretion from K and L-cells. However, the effects of meat hydrolysate on insulin secretion were more potent in both cells compared with glucose. Results of enzyme-linked immunosorbent assays showed that L-cells secreted more insulin compared with K-cells regardless of the stimulator, although this difference was not statistically significant. Conclusion The responses of K and L-cells to stimulation with glucose or meat hydrolysate were generally comparable. Therefore, both K and L-cells show similar potential to be used as surrogate cells for insulin gene expression in vitro. The potential use of these cells for diabetic gene therapy warrants further investigation.

  14. Lipid-induced insulin resistance does not impair insulin access to skeletal muscle

    Science.gov (United States)

    Richey, Joyce M.; Castro, Ana Valeria B.; Broussard, Josiane L.; Ionut, Viorica; Bergman, Richard N.

    2015-01-01

    Elevated plasma free fatty acids (FFA) induce insulin resistance in skeletal muscle. Previously, we have shown that experimental insulin resistance induced by lipid infusion prevents the dispersion of insulin through the muscle, and we hypothesized that this would lead to an impairment of insulin moving from the plasma to the muscle interstitium. Thus, we infused lipid into our anesthetized canine model and measured the appearance of insulin in the lymph as a means to sample muscle interstitium under hyperinsulinemic euglycemic clamp conditions. Although lipid infusion lowered the glucose infusion rate and induced both peripheral and hepatic insulin resistance, we were unable to detect an impairment of insulin access to the lymph. Interestingly, despite a significant, 10-fold increase in plasma FFA, we detected little to no increase in free fatty acids or triglycerides in the lymph after lipid infusion. Thus, we conclude that experimental insulin resistance induced by lipid infusion does not reduce insulin access to skeletal muscle under clamp conditions. This would suggest that the peripheral insulin resistance is likely due to reduced cellular sensitivity to insulin in this model, and yet we did not detect a change in the tissue microenvironment that could contribute to cellular insulin resistance. PMID:25852002

  15. Adipose Tissue Insulin Resistance in Gestational Diabetes.

    Science.gov (United States)

    Tumurbaatar, Batbayar; Poole, Aaron T; Olson, Gayle; Makhlouf, Michel; Sallam, Hanaa S; Thukuntla, Shwetha; Kankanala, Sucharitha; Ekhaese, Obos; Gomez, Guillermo; Chandalia, Manisha; Abate, Nicola

    2017-03-01

    Gestational diabetes mellitus (GDM) is a metabolic disorder characterized by insulin resistance (IR) and altered glucose-lipid metabolism. We propose that ectonucleotide pyrophosphate phosphodiesterase-1 (ENPP1), a protein known to induce adipocyte IR, is a determinant of GDM. Our objective was to study ENPP1 expression in adipose tissue (AT) of obese pregnant women with or without GDM, as well as glucose tolerance in pregnant transgenic (Tg) mice with AT-specific overexpression of human ENPP1. AT biopsies and blood were collected from body mass index-matched obese pregnant women non-GDM (n = 6), GDM (n = 7), and nonpregnant controls (n = 6) undergoing cesarian section or elective surgeries, respectively. We measured the following: (1) Expression of key molecules involved in insulin signaling and glucose-lipid metabolism in AT; (2) Plasma glucose and insulin levels and calculation of homeostasis model assessment of IR (HOMA-IR); (3) Intraperitoneal glucose tolerance test in AtENPP1 Tg pregnant mice. We found that: (1) Obese GDM patients have higher AT ENPP1 expression than obese non-GDM patients, or controls (P = 0.01-ANOVA). (2) ENPP1 expression level correlated negatively with glucose transporter 4 (GLUT4) and positively with insulin receptor substrate-1 (IRS-1) serine phosphorylation, and to other adipocyte functional proteins involved in glucose and lipid metabolism (P Pregnant AT ENPP1 Tg mice showed higher plasma glucose than wild type animals (P = 0.046-t test on area under curve [AUC] glucose ). Our results provide evidence of a causative link between ENPP1 and alterations in insulin signaling, glucose uptake, and lipid metabolism in subcutaneous abdominal AT of GDM, which may mediate IR and hyperglycemia in GDM.

  16. Circulating 25-hydroxyvitamin D and insulin resistance in older adults: The Cardiovascular Health Study

    Science.gov (United States)

    Danziger, John; Biggs, Mary L.; Niemi, Matt; Ix, Joachim H.; Kizer, Jorge R.; Djoussé, Luc; de Boer, Ian H.; Siscovick, David S.; Kestenbaum, Bryan; Mukamal, Kenneth J.

    2014-01-01

    Background Despite extensive study, the role of vitamin D in insulin resistance and secretion remains unclear. Objective To examine the cross-sectional and longitudinal relationships between 25-hydroxyvitamin D (25(OH)D) concentrations and indices of insulin resistance and secretion in older adults. Methods and Results Among 2134 participants of the Cardiovascular Health Study who were free from cardiovascular disease, we measured serum 25(OH)D concentrations in samples collected in 1992–1993. We examined insulin resistance and secretion using Homeostasis Model Assessment (HOMA) estimates cross-sectionally and among 1469 participants who had repeated HOMA measures four years later (1996–1997). In cross-sectional analysis, each 10 ng/mL increment in 25(OH)D concentration was associated with a 0.09 lower adjusted HOMA-IR [95%CI (−0.17, −0.02), p=0.01]. However, baseline 25(OH)D concentrations were not associated with change in HOMA-IR over 4 years of follow up (p=0.48). 25(OH)D concentrations were not associated with insulin secretion, as determined by HOMA-β, in either cross-sectional or longitudinal analysis. Conclusions Circulating 25(OH)D concentrations are associated with lower insulin resistance in cross-sectional but not longitudinal analyses. Whether this reflects residual confounding in cross-sectional analyses or the short-term nature of the relationship between vitamin D and insulin sensitivity will require trials with repeated measures of these factors. PMID:23987236

  17. Fructose, insulin resistance, and metabolic dyslipidemia

    Directory of Open Access Journals (Sweden)

    Adeli Khosrow

    2005-02-01

    Full Text Available Abstract Obesity and type 2 diabetes are occurring at epidemic rates in the United States and many parts of the world. The "obesity epidemic" appears to have emerged largely from changes in our diet and reduced physical activity. An important but not well-appreciated dietary change has been the substantial increase in the amount of dietary fructose consumption from high intake of sucrose and high fructose corn syrup, a common sweetener used in the food industry. A high flux of fructose to the liver, the main organ capable of metabolizing this simple carbohydrate, perturbs glucose metabolism and glucose uptake pathways, and leads to a significantly enhanced rate of de novo lipogenesis and triglyceride (TG synthesis, driven by the high flux of glycerol and acyl portions of TG molecules from fructose catabolism. These metabolic disturbances appear to underlie the induction of insulin resistance commonly observed with high fructose feeding in both humans and animal models. Fructose-induced insulin resistant states are commonly characterized by a profound metabolic dyslipidemia, which appears to result from hepatic and intestinal overproduction of atherogenic lipoprotein particles. Thus, emerging evidence from recent epidemiological and biochemical studies clearly suggests that the high dietary intake of fructose has rapidly become an important causative factor in the development of the metabolic syndrome. There is an urgent need for increased public awareness of the risks associated with high fructose consumption and greater efforts should be made to curb the supplementation of packaged foods with high fructose additives. The present review will discuss the trends in fructose consumption, the metabolic consequences of increased fructose intake, and the molecular mechanisms leading to fructose-induced lipogenesis, insulin resistance and metabolic dyslipidemia.

  18. Effect of Magnesium Supplements on Insulin Secretion After Kidney Transplantation: A Randomized Controlled Trial.

    Science.gov (United States)

    Van Laecke, Steven; Caluwe, Rogier; Huybrechts, Inge; Nagler, Evi V; Vanholder, Raymond; Peeters, Patrick; Van Vlem, Bruno; Van Biesen, Wim

    2017-08-29

    BACKGROUND Hypomagnesemia is associated with a disturbed glucose metabolism. Insulin hypo-secretion predicts diabetes in the general population and in transplant recipients. We aimed to assess whether magnesium improves insulin secretion and glycemic control after transplantation in prevalent hypomagnesemic kidney transplant recipients. MATERIAL AND METHODS We conducted an open-label, randomized, parallel-group study. Eligible participants were adults more than 4 months after kidney transplantation on tacrolimus with persisting serum magnesium concentrations food-frequency questionnaire. All analyses were done on an intention-to-treat basis. RESULTS Magnesium with a mean daily dose of 688±237mg in the treatment group failed to lead to significant differences between the 2 groups in FPIR, fasting glucose, HbA1c, or HOMA-IR. Persisting hypomagnesemia was very common and associated with more insulin hypo-secretion, glucose intolerance, and lower dietary magnesium intake (142±56 versus 202±90 mg; p=0.015) as compared to patients with a rise in serum magnesium over 6 months. CONCLUSIONS Magnesium supplementation does not improve insulin secretion in stable hypomagnesemic kidney transplant recipients on tacrolimus. Persisting hypomagnesemia is associated with impaired glucose tolerance, insulin hypo-secretion, and dietary factors.

  19. Acute stimulation of brain mu opioid receptors inhibits glucose-stimulated insulin secretion via sympathetic innervation.

    Science.gov (United States)

    Tudurí, Eva; Beiroa, Daniel; Stegbauer, Johannes; Fernø, Johan; López, Miguel; Diéguez, Carlos; Nogueiras, Rubén

    2016-11-01

    Pancreatic insulin-secreting β-cells express opioid receptors, whose activation by opioid peptides modulates hormone secretion. Opioid receptors are also expressed in multiple brain regions including the hypothalamus, where they play a role in feeding behavior and energy homeostasis, but their potential role in central regulation of glucose metabolism is unknown. Here, we investigate whether central opioid receptors participate in the regulation of insulin secretion and glucose homeostasis in vivo. C57BL/6J mice were acutely treated by intracerebroventricular (i.c.v.) injection with specific agonists for the three main opioid receptors, kappa (KOR), delta (DOR) and mu (MOR) opioid receptors: activation of KOR and DOR did not alter glucose tolerance, whereas activation of brain MOR with the specific agonist DAMGO blunted glucose-stimulated insulin secretion (GSIS), reduced insulin sensitivity, increased the expression of gluconeogenic genes in the liver and, consequently, impaired glucose tolerance. Pharmacological blockade of α2A-adrenergic receptors prevented DAMGO-induced glucose intolerance and gluconeogenesis. Accordingly, DAMGO failed to inhibit GSIS and to impair glucose tolerance in α2A-adrenoceptor knockout mice, indicating that the effects of central MOR activation on β-cells are mediated via sympathetic innervation. Our results show for the first time a new role of the central opioid system, specifically the MOR, in the regulation of insulin secretion and glucose metabolism. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Similar weight-adjusted insulin secretion and insulin sensitivity in short-duration late autoimmune diabetes of adulthood (LADA) and Type 2 diabetes

    DEFF Research Database (Denmark)

    Juhl, C B; Bradley, U; Holst, Jens Juul

    2014-01-01

    AIMS: To explore insulin sensitivity and insulin secretion in people with latent autoimmune diabetes in adulthood (LADA) compared with that in people with Type 2 diabetes. METHODS: A total of 12 people with LADA, defined as glutamic acid decarboxylase (GAD) antibody positivity and > 1 year...... of insulin independency (group A) were age-matched pairwise to people with Type 2 diabetes (group B) and to six people with Type 2 diabetes of similar age and BMI (group C). β-cell function (first-phase insulin secretion and assessment of insulin pulsatility), insulin sensitivity (hyperinsulinemic......-euglycemic clamp) and metabolic response during a mixed meal were studied. RESULTS: Both first-phase insulin secretion and insulin release during the meal were greater (P = 0.05 and P = 0.009, respectively) in Type 2 diabetes as compared with LADA; these differences were lost on adjustment for BMI (group C...

  1. Insulin Stimulates S100B Secretion and These Proteins Antagonistically Modulate Brain Glucose Metabolism.

    Science.gov (United States)

    Wartchow, Krista Minéia; Tramontina, Ana Carolina; de Souza, Daniela F; Biasibetti, Regina; Bobermin, Larissa D; Gonçalves, Carlos-Alberto

    2016-06-01

    Brain metabolism is highly dependent on glucose, which is derived from the blood circulation and metabolized by the astrocytes and other neural cells via several pathways. Glucose uptake in the brain does not involve insulin-dependent glucose transporters; however, this hormone affects the glucose influx to the brain. Changes in cerebrospinal fluid levels of S100B (an astrocyte-derived protein) have been associated with alterations in glucose metabolism; however, there is no evidence whether insulin modulates glucose metabolism and S100B secretion. Herein, we investigated the effect of S100B on glucose metabolism, measuring D-(3)H-glucose incorporation in two preparations, C6 glioma cells and acute hippocampal slices, and we also investigated the effect of insulin on S100B secretion. Our results showed that: (a) S100B at physiological levels decreases glucose uptake, through the multiligand receptor RAGE and mitogen-activated protein kinase/ERK signaling, and (b) insulin stimulated S100B secretion via PI3K signaling. Our findings indicate the existence of insulin-S100B modulation of glucose utilization in the brain tissue, and may improve our understanding of glucose metabolism in several conditions such as ketosis, streptozotocin-induced dementia and pharmacological exposure to antipsychotics, situations that lead to changes in insulin signaling and extracellular levels of S100B.

  2. FTO Inhibits Insulin Secretion and Promotes NF-κB Activation through Positively Regulating ROS Production in Pancreatic β cells.

    Directory of Open Access Journals (Sweden)

    Hong-Qi Fan

    Full Text Available FTO (Fat mass and obesity-associated is associated with increased risk of obesity and type 2 diabetes incurrence. Pancreas islet β cells dysfunction and insulin resistance are major causes of type 2 diabetes. However, whether FTO plays an important functional role in pancreatic β cells as well as the related molecular mechanism is still unclear. In the present study, the tissue expression profile of FTO was firstly determined using quantitative PCR and western blot. FTO is widely expressed in various tissues and presented with relative high expression in pancreas tissue, especially in endocrine pancreas. FTO overexpression in MIN6 cells achieved by lentivirus delivery significantly inhibits insulin secretion in the presence of glucose stimulus as well as KCl. FTO silence has no effect on insulin secretion of MIN6 cells. However, FTO overexpression doesn't affect the transcription of insulin gene. Furthermore, reactive oxygen species (ROS production and NF-κB activation are significantly promoted by FTO overexpression. Inhibition of intracellular ROS production by N-acetyl-L-cysteine (NAC can alleviate NF-κB activation and restore the insulin secretion mediated by FTO overexpression. A whole transcript-microarray is employed to analyze the differential gene expression mediated by FTO overexpression. The genes which are modulated by FTO are involved in many important biological pathways such as G-protein coupled receptor signaling and NF-κB signaling. Therefore, our study indicates that FTO may contribute to pancreas islet β cells dysfunction and the inhibition of FTO activity is a potential target for the treatment of diabetes.

  3. Early phase glucagon and insulin secretory abnormalities, but not incretin secretion, are similarly responsible for hyperglycemia after ingestion of nutrients

    DEFF Research Database (Denmark)

    Yabe, Daisuke; Kuroe, Akira; Watanabe, Koin

    2015-01-01

    AIMS: Hypersecretion of glucagon and reduced insulin secretion both contribute to hyperglycemia in type 2 diabetes (T2DM). However, the relative contributions of impaired glucagon and insulin secretions in glucose excursions at the various stages of T2DM development remain to be determined. METHODS...... secretions but not incretin secretion are involved in hyperglycemia after ingestion of nutrients in T2DM of even a short duration....

  4. Secretome Analysis of Lipid-Induced Insulin Resistance in Skeletal Muscle Cells by a Combined Experimental and Bioinformatics Workflow

    DEFF Research Database (Denmark)

    Deshmukh, Atul S; Cox, Juergen; Jensen, Lars Juhl

    2015-01-01

    , in principle, allows an unbiased and comprehensive analysis of cellular secretomes; however, the distinction of bona fide secreted proteins from proteins released upon lysis of a small fraction of dying cells remains challenging. Here we applied highly sensitive MS and streamlined bioinformatics to analyze......-resistant conditions. Our study demonstrates an efficient combined experimental and bioinformatics workflow to identify putative secreted proteins from insulin-resistant skeletal muscle cells, which could easily be adapted to other cellular models....

  5. Serum Insulin, Glucose, Indices of Insulin Resistance, and Risk of Lung Cancer.

    Science.gov (United States)

    Argirion, Ilona; Weinstein, Stephanie J; Männistö, Satu; Albanes, Demetrius; Mondul, Alison M

    2017-10-01

    Background: Although insulin may increase the risk of some cancers, few studies have examined fasting serum insulin and lung cancer risk. Methods: We examined serum insulin, glucose, and indices of insulin resistance [insulin:glucose molar ratio and homeostasis model assessment of insulin resistance (HOMA-IR)] and lung cancer risk using a case-cohort study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study of Finnish men. A total of 196 cases and 395 subcohort members were included. Insulin and glucose were measured in fasting serum collected 5 to 12 years before diagnosis. Cox proportional hazards models were utilized to estimate the relative risk of lung cancer. Results: The average time between blood collection and lung cancer was 9.6 years. Fasting serum insulin levels were 8.7% higher in subcohort members than cases. After multivariable adjustment, men in the fourth quartile of insulin had a significantly higher risk of lung cancer than those in the first quartile [HR = 2.10; 95% confidence interval (CI), 1.12-3.94]. A similar relationship was seen with HOMA-IR (HR = 1.83; 95% CI, 0.99-3.38). Risk was not strongly associated with glucose or the insulin:glucose molar ratio ( P trend = 0.55 and P trend = 0.27, respectively). Conclusions: Higher fasting serum insulin concentrations, as well as the presence of insulin resistance, appear to be associated with an elevated risk of lung cancer development. Impact: Although insulin is hypothesized to increase risk of some cancers, insulin and lung cancer remain understudied. Higher insulin levels and insulin resistance were associated with increased lung cancer risk. Although smoking cessation is the best method of lung cancer prevention, other lifestyle changes that affect insulin concentrations and sensitivity may reduce lung cancer risk. Cancer Epidemiol Biomarkers Prev; 26(10); 1519-24. ©2017 AACR . ©2017 American Association for Cancer Research.

  6. Molecular Mechanisms of Chromium in Alleviating Insulin Resistance

    Science.gov (United States)

    Hua, Yinan; Clark, Suzanne; Ren, Jun; Sreejayan, Nair

    2011-01-01

    Type 2 diabetes is often associated with obesity, dyslipidemia, and cardiovascular anomalies and is a major health problem approaching global epidemic proportions. Insulin resistance, a prediabetic condition, precedes the onset of frank type 2 diabetes and offers potential avenues for early intervention to treat the disease. Although lifestyle modifications and exercise can reduce the incidence of diabetes, compliance has proved to be difficult, warranting pharmacological interventions. However, most of the currently available drugs that improve insulin sensitivity have adverse effects. Therefore, attractive strategies to alleviate insulin resistance include dietary supplements. One such supplement is chromium, which has been shown reduce insulin resistance in some, but not all, studies. Furthermore, the molecular mechanisms of chromium in alleviating insulin resistance remain elusive. This review examines emerging reports on the effect of chromium, as well as molecular and cellular mechanisms by which chromium may provide beneficial effects in alleviating insulin resistance. PMID:22423897

  7. p53- and ERK7-dependent ribosome surveillance response regulates Drosophila insulin-like peptide secretion.

    Directory of Open Access Journals (Sweden)

    Kiran Hasygar

    2014-11-01

    Full Text Available Insulin-like signalling is a conserved mechanism that coordinates animal growth and metabolism with nutrient status. In Drosophila, insulin-producing median neurosecretory cells (IPCs regulate larval growth by secreting insulin-like peptides (dILPs in a diet-dependent manner. Previous studies have shown that nutrition affects dILP secretion through humoral signals derived from the fat body. Here we uncover a novel mechanism that operates cell autonomously in the IPCs to regulate dILP secretion. We observed that impairment of ribosome biogenesis specifically in the IPCs strongly inhibits dILP secretion, which consequently leads to reduced body size and a delay in larval development. This response is dependent on p53, a known surveillance factor for ribosome biogenesis. A downstream effector of this growth inhibitory response is an atypical MAP kinase ERK7 (ERK8/MAPK15, which is upregulated in the IPCs following impaired ribosome biogenesis as well as starvation. We show that ERK7 is sufficient and essential to inhibit dILP secretion upon impaired ribosome biogenesis, and it acts epistatically to p53. Moreover, we provide evidence that p53 and ERK7 contribute to the inhibition of dILP secretion upon starvation. Thus, we conclude that a cell autonomous ribosome surveillance response, which leads to upregulation of ERK7, inhibits dILP secretion to impede tissue growth under limiting dietary conditions.

  8. Role of sialic acid in insulin action and the insulin resistance of diabetes mellitus

    International Nuclear Information System (INIS)

    Salhanick, A.I.; Amatruda, J.M.

    1988-01-01

    Adipocytes treated with neuraminidase show markedly reduced responsiveness to insulin without any alteration in insulin binding. In addition, several studies have separately demonstrated both insulin resistance and decreases in membrane sialic acid content and associated biosynthetic enzymes in diabetes mellitus. In the present study, the authors investigated the role that sialic acid residues may play in insulin action and in the hepatic insulin resistance associated with nonketotic diabetes. Primary cultures of hepatocytes from normal rats treated with neuraminidase demonstrated a dose-dependent decrease in insulin-stimulated lipogenesis. At a concentration of neuraminidase that decreases insulin action by 50%, 23% of total cellular sialic acid content was released. Neuraminidase-releasable sialic acid was significantly decreased in hepatocytes from diabetic rats and this was associated with significant insulin resistance. Treatment of hepatocytes from diabetic rats with cytidine 5'-monophospho-N-acetylneuraminic acid (CMP-NANA) enhanced insulin responsiveness 39%. The enhanced insulin responsiveness induced by CMP-NANA was blocked by cytidine 5'-monophosphate (CMP) suggesting that the CMP-NANA effect was catalyzed by a cell surface sialyl-transferase. CMP reduced neuraminidase-releasable [ 14 C]sialic acid incorporation into hepatocytes by 43%. The data demonstrate a role for cell surface sialic acid residues in hepatic insulin action and support a role for decreased cell surface sialic acid residues in the insulin resistance of diabetes mellitus

  9. Acceptance of insulin therapy: a long shot? Psychological insulin resistance in primary care

    NARCIS (Netherlands)

    Woudenberg, Y. J. C.; Lucas, C.; Latour, C.; Scholte Op Reimer, W. J. M.

    2012-01-01

    Diabet. Med. 29, 796802 (2012) Abstract Aim To explore which factors are associated with psychological insulin resistance in insulin-naive patients with Type 2 diabetes in primary care. Methods A sample of 101 insulin-naive patients with Type 2 diabetes completed self-administered questionnaires

  10. Insulin resistance in brain and possible therapeutic approaches.

    Science.gov (United States)

    Cetinkalp, Sevki; Simsir, Ilgin Y; Ertek, Sibel

    2014-01-01

    Although the brain has long been considered an insulin-independent organ, recent research has shown that insulin has significant effects on the brain, where it plays a role in maintaining glucose and energy homeostasis. To avoid peripheral insulin resistance, the brain may act via hypoinsulinemic responses, maintaining glucose metabolism and insulin sensitivity within its own confines; however, brain insulin resistance may develop due to environmental factors. Insulin has two important functions in the brain: controlling food intake and regulating cognitive functions, particularly memory. Notably, defects in insulin signaling in the brain may contribute to neurodegenerative disorders. Insulin resistance may damage the cognitive system and lead to dementia states. Furthermore, inflammatory processes in the hypothalamus, where insulin receptors are expressed at high density, impair local signaling systems and cause glucose and energy metabolism disorders. Excessive caloric intake and high-fat diets initiate insulin and leptin resistance by inducing mitochondrial dysfunction and endoplasmic reticulum stress in the hypothalamus. This may lead to obesity and diabetes mellitus (DM). Exercise can enhance brain and hypothalamic insulin sensitivity, but it is the option least preferred and/or continuously practiced by the general population. Pharmacological treatments that increase brain and hypothalamic insulin sensitivity may provide new insights into the prevention of dementia disorders, obesity, and type 2 DM in the future.

  11. Peripheral nervous system insulin resistance in ob/ob mice

    Science.gov (United States)

    2013-01-01

    Background A reduction in peripheral nervous system (PNS) insulin signaling is a proposed mechanism that may contribute to sensory neuron dysfunction and diabetic neuropathy. Neuronal insulin resistance is associated with several neurological disorders and recent evidence has indicated that dorsal root ganglion (DRG) neurons in primary culture display altered insulin signaling, yet in vivo results are lacking. Here, experiments were performed to test the hypothesis that the PNS of insulin-resistant mice displays altered insulin signal transduction in vivo. For these studies, nondiabetic control and type 2 diabetic ob/ob mice were challenged with an intrathecal injection of insulin or insulin-like growth factor 1 (IGF-1) and downstream signaling was evaluated in the DRG and sciatic nerve using Western blot analysis. Results The results indicate that insulin signaling abnormalities documented in other “insulin sensitive” tissues (i.e. muscle, fat, liver) of ob/ob mice are also present in the PNS. A robust increase in Akt activation was observed with insulin and IGF-1 stimulation in nondiabetic mice in both the sciatic nerve and DRG; however this response was blunted in both tissues from ob/ob mice. The results also suggest that upregulated JNK activation and reduced insulin receptor expression could be contributory mechanisms of PNS insulin resistance within sensory neurons. Conclusions These findings contribute to the growing body of evidence that alterations in insulin signaling occur in the PNS and may be a key factor in the pathogenesis of diabetic neuropathy. PMID:24252636

  12. Lean mass and insulin resistance in women with polycystic ovary syndrome.

    Science.gov (United States)

    Comerford, Kevin B; Almario, Rogelio U; Kim, Kyoungmi; Karakas, Sidika E

    2012-09-01

    Insulin resistance is common in women with polycystic ovary syndrome (PCOS). Muscle is the major tissue utilizing glucose while excess adipose tissue relates to insulin resistance. Thus, body composition is likely to be an important regulator of insulin sensitivity. Thirty-nine PCOS patients (age: 29.9±1.0 years; BMI: 33.8±1.2 kg/m(2)) participated in a cross sectional study. Body composition was measured by dual energy x-ray absorptiometry (DEXA). Insulin resistance and secretion were assessed using oral glucose tolerance test (OGTT) and frequently sampled intravenous glucose tolerance test (FS-IVGTT). In contrast with the conventional expectations, lean mass correlated directly (Plean mass (52.8±1.8 vs 44.4±1.6 kg), those with higher lean mass had a higher glucose response during OGTT (AUC(Glucose); P=.034). In contrast, 17 pairs matched for lean mass (48.7±1.7 and 48.9±1.6 kg) but discordant for fat mass (43.3±2.6 vs 30.3±8.9 kg) showed no differences in insulin resistance parameters. These novel findings indicate that lean mass relates directly to insulin resistance in PCOS. Published by Elsevier Inc.

  13. Globular adiponectin ameliorates metabolic insulin resistance via AMPK-mediated restoration of microvascular insulin responses

    Science.gov (United States)

    Zhao, Lina; Fu, Zhuo; Wu, Jing; Aylor, Kevin W; Barrett, Eugene J; Cao, Wenhong; Liu, Zhenqi

    2015-01-01

    Abstract Hypoadiponectinaemia is closely associated with endothelial dysfunction and insulin resistance, and microvasculature plays a critical role in the regulation of insulin action in muscle. Here we tested whether adiponectin replenishment could improve metabolic insulin sensitivity in male rats fed a high-fat diet (HFD) via the modulation of microvascular insulin responses. Male Sprague–Dawley rats were fed either a HFD or low-fat diet (LFD) for 4 weeks. Small resistance artery myograph changes in tension, muscle microvascular recruitment and metabolic response to insulin were determined. Compared with rats fed a LFD, HFD feeding abolished the vasodilatory actions of globular adiponectin (gAd) and insulin on pre-constricted distal saphenous arteries. Pretreatment with gAd improved insulin responses in arterioles isolated from HFD rats, which was blocked by AMP-activated protein kinase (AMPK) inhibition. Similarly, HFD abolished microvascular responses to either gAd or insulin and decreased insulin-stimulated glucose disposal by ∼60%. However, supplementing gAd fully rescued insulin’s microvascular action and significantly improved the metabolic responses to insulin in HFD male rats and these actions were abolished by inhibition of either AMPK or nitric oxide production. We conclude that HFD induces vascular adiponectin and insulin resistance but gAd administration can restore vascular insulin responses and improve insulin’s metabolic action via an AMPK- and nitric oxide-dependent mechanism in male rats. Key points Adiponectin is an adipokine with anti-inflammatory and anti-diabetic properties. Hypoadiponectinaemia is closely associated with endothelial dysfunction and insulin resistance in obesity and diabetes. Insulin resistance is present in muscle microvasculature and this may contribute to decreased insulin delivery to, and action in, muscle. In this study we examined whether adiponectin ameliorates metabolic insulin resistance by affecting muscle

  14. Decrease of glucose-induced insulin secretion of pancreatic rat islets after irradiation in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Heinzmann, D; Nadrowitz, R; Besch, W; Schmidt, W; Hahn, H J

    1983-01-01

    Irradiation of pancreatic rat islets up to a dose of 2.5 Gy did neither alter glucose-nor IBMX-induced insulin secretion studied in vitro. The insulin as well as glucagon content of irradiated islets were similar as in the control tissue. This was also true in islets irradiated with 25 Gy which were characterized by a decreased insulin secretion in the presence of glucose and IBMX, respectively. Since we did not find indications of an enhanced hormone output in the radiation medium, we want to suggest that higher irradiation doses affect insulin release of pancreatic islets in vitro. This observation has to be taken into account for application of radioimmunosuppression for transplantation.

  15. Hormone-sensitive lipase deficiency suppresses insulin secretion from pancreatic islets of Lepob/ob mice

    International Nuclear Information System (INIS)

    Sekiya, Motohiro; Yahagi, Naoya; Tamura, Yoshiaki; Okazaki, Hiroaki; Igarashi, Masaki; Ohta, Keisuke; Takanashi, Mikio; Kumagai, Masayoshi; Takase, Satoru; Nishi, Makiko; Takeuchi, Yoshinori; Izumida, Yoshihiko; Kubota, Midori; Ohashi, Ken; Iizuka, Yoko; Yagyu, Hiroaki; Gotoda, Takanari; Nagai, Ryozo; Shimano, Hitoshi; Yamada, Nobuhiro

    2009-01-01

    It has long been a matter of debate whether the hormone-sensitive lipase (HSL)-mediated lipolysis in pancreatic β-cells can affect insulin secretion through the alteration of lipotoxicity. We generated mice lacking both leptin and HSL (Lep ob/ob /HSL -/- ) and explored the role of HSL in pancreatic β-cells in the setting of obesity. Lep ob/ob /HSL -/- developed elevated blood glucose levels and reduced plasma insulin levels compared with Lep ob/ob /HSL +/+ in a fed state, while the deficiency of HSL did not affect glucose homeostasis in Lep +/+ background. The deficiency of HSL exacerbated the accumulation of triglycerides in Lep ob/ob islets, leading to reduced glucose-stimulated insulin secretion. The deficiency of HSL also diminished the islet mass in Lep ob/ob mice due to decreased cell proliferation. In conclusion, HSL affects insulin secretary capacity especially in the setting of obesity.

  16. Advanced glycation end products impair glucose-induced insulin secretion from rat pancreatic β-cells.

    Science.gov (United States)

    Hachiya, Hiroyuki; Miura, Yoshikazu; Inoue, Ken-Ichi; Park, Kyung Hwa; Takeuchi, Masayoshi; Kubota, Keiichi

    2014-02-01

    Advanced glycation end products (AGEs) are derivative compounds generated from non-enzymatic glycosylation and oxidation. In comparison with glucose-derived AGEs (Glu-AGEs), glyceraldehyde-derived AGEs (Glycer-AGEs) have stronger toxicity to living systems. In this study, we compared the effects of Glu-AGE and Glycer-AGE on insulin secretion. Rat pancreatic islets were isolated by collagenase digestion and primary-cultured in the presence of 0.1 mg/ml bovine serum albumin (BSA) or 0.1 mg/ml Glu-AGE or Glycer-AGE-albumin. After 48 h of culture, we performed an insulin secretion test and identified the defects by a battery of rescue experiments [corrected]. Also, mRNA expression of genes associated with insulin secretion was measured. Insulin secretion induced by a high glucose concentration was 164.1 ± 6.0, 124.4 ± 4.4 (P < 0.05) and 119.8 ± 7.1 (P < 0.05) μU/3 islets/h in the presence of BSA, Glu-AGE, and Glycer-AGE, respectively. Inhibition of insulin secretion by Glu-AGE or Glycer-AGE was rescued by a high extracellular potassium concentration, tolbutamide and α-ketoisocaproic acid, but not by glyceraldehyde, dihydroxacetone, methylpyruvate, glucagon-like peptide-1 and acetylcholine. Glu-AGE or Glycer-AGE reduced the expression of the malate dehydrogenase (Mdh1/2) gene, which plays a critical role in the nicotinamide adenine dinucleotide (NADH) shuttle. Despite its reported cytotoxicity, the effects of Glycer-AGE on insulin secretion are similar to those of Glu-AGE. © 2013 Japanese Society of Hepato-Biliary-Pancreatic Surgery.

  17. Study of insulin resistance and insulin secretion function in overweight and obese subjects with endothelial dysfunction%肥胖伴内皮功能异常者胰岛抵抗与胰岛β细胞功能状况的研究

    Institute of Scientific and Technical Information of China (English)

    朱旅云; 刘坤申

    2004-01-01

    Objective: To investigate the impacts of endothelial dysfunction on insulin resistance (IR) and insulin secretion function in overweight and obese subjects. Methods: 296 overweight and obese subjects were divided into impaired and normal endothelial function (A and B group, respectively). 87 normal weight and healthy subjects without endothelial dysfunction acted as normal control ( C group). The body mass index (BMI), waist circumference (W), waist-hip ratio (WHR), SBP, DBP, fasting blood glucose (FBG), and insulin (FINS), postprandial 2h blood glucose (PBG) and insulin (PINS), lipid profile, creatnine (Cr) and uric acid (Ur) were measured. Homeostasis model assessment (HOMA) was applied to calculate HOMA - IR as an index of IR and HOMA - β as an index of beta - cell function. Results: BMI, W, WHR, SBP, DBP, TG and Ur in both A and B groups were higher than in C group (P<0.05 ~0.001), and compared with Group B, W, WHR, DBP, TG and Ur in group A were significantly increased (P<0.05 ~0.01 ), FBG, FINS, HOMA - IR and GOMA - β in group A were significantly higher than in Group B was similar to Group C in HOMA - β. The flow - mediated endothelium - dependent dilation in Group A was significantly higher than that in Group B (P <0.05 ~ 0.001 ). Group B was similar to Group C in HOMA - β. The flow - mediated endothelium - dependent dilatation in Group A was significantly lower than th at inlatter two groups. The flow - mediated dilatation was closely negatively correlated with HOMA - IR and HOMA - β (γ= -0. 197, P <0.05 andγ= -0. 136, P <0.01 ) but there were no significant correlation in B and C groups. Conclusion: Endothelial dysfunction is an important risk factor affecting the clustering of cardiovascular risk factors, the occurring and developing of IR in overweight and obese subjects.%目的探讨内皮功能障碍对肥胖者胰岛素抵抗(IR)及胰岛β细胞功能的影响.方法296例单纯肥胖者被分为内皮功能异常组(A组)与

  18. Conditioned insulin secretion and meal feeding in rats.

    Science.gov (United States)

    Woods, S C; Vasselli, J R; Kaestner, E; Szakmary, G A; Milburn, P; Vitiello, M V

    1977-02-01

    Previous researchers have reported that rats placed upon a feeding regimen such that they receive only 2 hr of food per day (meal-fed rats) develop hyperinsulinemia at the time of the day associated with feeding, even in the absence of food. Controls fed ad lib had no such response. In a series of several experiments, meal-fed rats had elevated insulin levels at only the specific time of the day associated with feeding, and the increment of insulin at that time could be eliminated with atropine. Free-feeding controls, on the other hand, always had higher insulin levels than the meal-fed rats, did not have an elevation of insulin at the time of the day that the meal-fed rats normally ate, and had insulin values that were unaffected by atropine. Further experimentation showed that hyperinsulinemia could become associated with arbitrary stimuli always associated with eating for meal-fed rats. It is concluded that the hyperinsulinemia of meal-fed rats associated with their feeding time is a learned response.

  19. Metabolic syndrome and insulin resistance in obese adolescents

    Directory of Open Access Journals (Sweden)

    Amanda Oliva Gobato

    2014-03-01

    Full Text Available Objective: To verify the prevalence of metabolic syndrome and insulin resistance in obese adolescents and its relationship with different body composition indicators. Methods: A cross-sectional study comprising 79 adolescents aged ten to 18 years old. The assessed body composition indicators were: body mass index (BMI, body fat percentage, abdominal circumference, and subcutaneous fat. The metabolic syndrome was diagnosed according to the criteria proposed by Cook et al. The insulin resistance was determined by the Homeostasis Model Assessment for Insulin Resistance (HOMA-IR index for values above 3.16. The analysis of ROC curves was used to assess the BMI and the abdominal circumference, aiming to identify the subjects with metabolic syndrome and insulin resistance. The cutoff point corresponded to the percentage above the reference value used to diagnose obesity. Results: The metabolic syndrome was diagnosed in 45.5% of the patients and insulin resistance, in 29.1%. Insulin resistance showed association with HDL-cholesterol (p=0.032 and with metabolic syndrome (p=0.006. All body composition indicators were correlated with insulin resistance (p<0.01. In relation to the cutoff point evaluation, the values of 23.5 and 36.3% above the BMI reference point allowed the identification of insulin resistance and metabolic syndrome. The best cutoff point for abdominal circumference to identify insulin resistance was 40%. Conclusions: All body composition indicators, HDL-cholesterol and metabolic syndrome showed correlation with insulin resistance. The BMI was the most effective anthropometric indicator to identify insulin resistance.

  20. An ancestral role for the mitochondrial pyruvate carrier in glucose-stimulated insulin secretion

    OpenAIRE

    McCommis, Kyle S.; Hodges, Wesley T.; Bricker, Daniel K.; Wisidagama, Dona R.; Compan, Vincent; Remedi, Maria S.; Thummel, Carl S.; Finck, Brian N.

    2016-01-01

    Objective: Transport of pyruvate into the mitochondrial matrix by the Mitochondrial Pyruvate Carrier (MPC) is an important and rate-limiting step in its metabolism. In pancreatic β-cells, mitochondrial pyruvate metabolism is thought to be important for glucose sensing and glucose-stimulated insulin secretion. Methods: To evaluate the role that the MPC plays in maintaining systemic glucose homeostasis, we used genetically-engineered Drosophila and mice with loss of MPC activity in insulin-prod...

  1. Circulating Glucagon 1-61 Regulates Blood Glucose by Increasing Insulin Secretion and Hepatic Glucose Production

    DEFF Research Database (Denmark)

    Wewer Albrechtsen, Nicolai J.; Kuhre, Rune E.; Hornburg, Daniel

    2017-01-01

    that PG 1-61 dose-dependently increases levels of cAMP, through the glucagon receptor, and increases insulin secretion and protein levels of enzymes regulating glycogenolysis and gluconeogenesis. In rats, PG 1-61 increases blood glucose and plasma insulin and decreases plasma levels of amino acids in......Glucagon is secreted from pancreatic α cells, and hypersecretion (hyperglucagonemia) contributes to diabetic hyperglycemia. Molecular heterogeneity in hyperglucagonemia is poorly investigated. By screening human plasma using high-resolution-proteomics, we identified several glucagon variants, among...... which proglucagon 1-61 (PG 1-61) appears to be the most abundant form. PG 1-61 is secreted in subjects with obesity, both before and after gastric bypass surgery, with protein and fat as the main drivers for secretion before surgery, but glucose after. Studies in hepatocytes and in β cells demonstrated...

  2. Treatment of severe insulin resistance in pregnancy with 500 units per milliliter of concentrated insulin.

    Science.gov (United States)

    Mendez-Figueroa, Hector; Maggio, Lindsay; Dahlke, Joshua D; Daley, Julie; Lopes, Vrishali V; Coustan, Donald R; Rouse, Dwight J

    2013-07-01

    To evaluate glycemic control and pregnancy outcomes among pregnant women with severe insulin resistance treated with 500 units/mL concentrated insulin. Retrospective analysis of gravid women with severe insulin resistance (need for greater than 100 units of insulin per injection or greater than 200 units/d) treated with either 500 units/mL concentrated insulin or conventional insulin therapy. We performed a two-part analysis: 1) between gravid women treated with and without 500 units/mL concentrated insulin; and 2) among gravid women treated with 500 units/mL concentrated insulin, comparing glycemic control before and after its initiation. Seventy-three pregnant women with severe insulin resistance were treated with 500 units/mL concentrated insulin and 78 with conventional insulin regimens. Patients treated with 500 units/mL concentrated insulin were older and more likely to have type 2 diabetes mellitus. Average body mass index was comparable between both groups (38.6 compared with 40.4, P=.11) as were obstetric and perinatal outcomes and glycemic control during the last week of gestation. Within the 500 units/mL concentrated insulin cohort, after initiation of this medication, fasting and postprandial blood glucose concentrations improved. However, the rates of blood glucose values less than 60 mg/dL and less than 50 mg/dL were higher in the 500 units/mL concentrated insulin group after initiation than before, 4.8% compared with 2.0% (Pinsulin in severely obese insulin-resistant pregnant women confers similar glycemic control compared with traditional insulin regimens but may increase the risk of hypoglycemia. II.

  3. Saponins from the traditional medicinal plant Momordica charantia stimulate insulin secretion in vitro

    Science.gov (United States)

    Keller, Amy C.; Ma, Jun; Kavalier, Adam; He, Kan; Brillantes, Anne-Marie B.; Kennelly, Edward J.

    2012-01-01

    The antidiabetic activity of Momordica charantia (L.), Cucurbitaceae, a widely-used treatment for diabetes in a number of traditional medicine systems, was investigated in vitro. Antidiabetic activity has been reported for certain saponins isolated from M. charantia. In this study insulin secretion was measured in MIN6 β-cells incubated with an ethanol extract, saponin-rich fraction, and five purified saponins and cucurbitane triterpenoids from M. charantia, 3β,7β,25-trihydroxycucurbita-5,23(E)-dien-19-al (1), momordicine I (2), momordicine II (3), 3-hydroxycucurbita-5,24-dien-19-al-7,23-di-O-β-glucopyranoside (4), and kuguaglycoside G (5). Treatments were compared to incubation with high glucose (27 mM) and the insulin secretagogue, glipizide (50 μM). At 125 μg/ml, an LC-ToF-MS characterized saponin-rich fraction stimulated insulin secretion significantly more than the DMSO vehicle, p=0.02. At concentrations 10 and 25 μg/ml, compounds 3 and 5 also significantly stimulated insulin secretion as compared to the vehicle, p≤0.007, and p= 0.002, respectively. This is the first report of a saponin-rich fraction, and isolated compounds from M. charantia, stimulating insulin secretion in an in vitro, static incubation assay. PMID:22133295

  4. Relationship among resistance to the insulin and obesity in Zacatecas population

    International Nuclear Information System (INIS)

    Zapata R, P. G.; Badillo A, V.

    2012-10-01

    The Zacatecas State (Mexico) occupies the second national place in obesity, although the adults have a bigger incidence every time exist more minors that present this problem which can facilitate other illnesses like diabetes and hypertension. The first resistance references to the insulin were made by Himsworth in 1936, when he referred to insulin-resistant and insulin-sensitive diabetics. The resistance to the insulin, as event pathogen primary in the diabetes mellitus type 2 is derived of the obesity, what implies a subnormal biological response to the actions of the hormone in the carbohydrates, proteins and lipids metabolism. In this work was carried out a study of insulin levels for the Radioimmunoassay method in 40 patients with evident obesity and 8 patients with normal weight in order to evaluate these levels according to their age and abdominal circumference. Three correlations were made for both groups (obese and normal), the first correlation indicates the size of the waist with the insulin quantity, according to the arrangements that shows the correlation is bigger in all; what means that there is a great dependence among the size of the waist and the insulin quantity that contain. The second correlation is the age with the insulin that although is small, indicates that the age does not important for the insulin quantity that is secreted. The third and last realized correlation was of the age with the waist, and according to the results correlation also exists, but this is not significant as the first correlation. Therefore is considered existent the relationship between obesity and resistance to the insulin. (Author)

  5. Insulin resistance in drug naive patients with multiple sclerosis

    OpenAIRE

    Kostić Smiljana; Kolić Ivana; Raičević Ranko; Stojanović Zvezdana; Kostić Dejan; Dinčić Evica

    2017-01-01

    Background/Aim. Due to the fact that there is a relatively small number of data related to systemic insulin abnormalities in the multiple sclerosis (MS), the main objective of our study was to determine whether a dysbalance of glucose and insulin metabolism exist in patients with natural course of MS. Our hypothesis was that the metabolic disorder that characterizes state of the insulin resistance (IR) and reduced insulin sensitivity (IS) in untreated patie...

  6. Reproducible insulin secretion from isolated rat pancreas preparations using an organ bath.

    Science.gov (United States)

    Morita, Asuka; Ouchi, Motoshi; Terada, Misao; Kon, Hiroe; Kishimoto, Satoko; Satoh, Keitaro; Otani, Naoyuki; Hayashi, Keitaro; Fujita, Tomoe; Inoue, Ken-Ichi; Anzai, Naohiko

    2018-02-09

    Diabetes mellitus is a lifestyle-related disease that is characterized by inappropriate or diminished insulin secretion. Ex vivo pharmacological studies of hypoglycemic agents are often conducted using perfused pancreatic preparations. Pancreas preparations for organ bath experiments do not require cannulation and are therefore less complex than isolated perfused pancreas preparations. However, previous research has generated almost no data on insulin secretion from pancreas preparations using organ bath preparations. The purpose of this study was to investigate the applicability of isolated rat pancreas preparations using the organ bath technique in the quantitative analysis of insulin secretion from β-cells. We found that insulin secretion significantly declined during incubation in the organ bath, whereas it was maintained in the presence of 1 µM GLP-1. Conversely, amylase secretion exhibited a modest increase during incubation and was not altered in the presence of GLP-1. These results demonstrate that the pancreatic organ bath preparation is a sensitive and reproducible method for the ex vivo assessment of the pharmacological properties of hypoglycemic agents.

  7. High Serum Advanced Glycation End Products Are Associated with Decreased Insulin Secretion in Patients with Type 2 Diabetes: A Brief Report

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Okura

    2017-01-01

    Full Text Available Objective. Advanced glycation end products (AGEs are important in the pathophysiology of type 2 diabetes mellitus (T2DM. They directly cause insulin secretory defects in animal and cell culture models and may promote insulin resistance in nondiabetic subjects. We have developed a highly sensitive liquid chromatography-tandem mass spectrometry method for measuring AGEs in human serum. Here, we use this method to investigate the relationship between AGEs and insulin secretion and resistance in patients with T2DM. Methods. Our study involved 15 participants with T2DM not on medication and 20 nondiabetic healthy participants. We measured the AGE carboxyethyllysine (CEL, carboxymethyllysine (CML, and methyl-glyoxal-hydro-imidazolone (MG-H1. Plasma glucose and insulin were measured in these participants during a meal tolerance test, and the glucose disposal rate was measured during a euglycemic-hyperinsulinemic clamp. Results. CML and CEL levels were significantly higher in T2DM than non-DM participants. CML showed a significant negative correlation with insulin secretion, HOMA-%B, and a significant positive correlation with the insulin sensitivity index in T2DM participants. There was no correlation between any of the AGEs measured and glucose disposal rate. Conclusions. These results suggest that AGE might play a role in the development or prediction of insulin secretory defects in type 2 diabetes.

  8. Blueberries’ Impact on Insulin Resistance and Glucose Intolerance

    Directory of Open Access Journals (Sweden)

    April J. Stull

    2016-11-01

    Full Text Available Blueberries are a rich source of polyphenols, which include anthocyanin bioactive compounds. Epidemiological evidence indicates that incorporating blueberries into the diet may lower the risk of developing type 2 diabetes (T2DM. These findings are supported by pre-clinical and clinical studies that have shown improvements in insulin resistance (i.e., increased insulin sensitivity after obese and insulin-resistant rodents or humans consumed blueberries. Insulin resistance was assessed by homeostatic model assessment-estimated insulin resistance (HOMA-IR, insulin tolerance tests, and hyperinsulinemic-euglycemic clamps. Additionally, the improvements in glucose tolerance after blueberry consumption were assessed by glucose tolerance tests. However, firm conclusions regarding the anti-diabetic effect of blueberries cannot be drawn due to the small number of existing clinical studies. Although the current evidence is promising, more long-term, randomized, and placebo-controlled trials are needed to establish the role of blueberries in preventing or delaying T2DM.

  9. Metabolism and insulin signaling in common metabolic disorders and inherited insulin resistance.

    Science.gov (United States)

    Højlund, Kurt

    2014-07-01

    Type 2 diabetes, obesity and polycystic ovary syndrome (PCOS) are common metabolic disorders which are observed with increasing prevalences, and which are caused by a complex interplay between genetic and environmental factors, including increased calorie intake and physical inactivity. These metabolic disorders are all characterized by reduced plasma adiponectin and insulin resistance in peripheral tissues. Quantitatively skeletal muscle is the major site of insulin resistance. Both low plasma adiponectin and insulin resistance contribute to an increased risk of type 2 diabetes and cardiovascular disease. In several studies, we have investigated insulin action on glucose and lipid metabolism, and at the molecular level, insulin signaling to glucose transport and glycogen synthesis in skeletal muscle from healthy individuals and in obesity, PCOS and type 2 diabetes. Moreover, we have described a novel syndrome characterized by postprandial hyperinsulinemic hypoglycemia and insulin resistance. This syndrome is caused by a mutation in the tyrosine kinase domain of the insulin receptor gene (INSR). We have studied individuals with this mutation as a model of inherited insulin resistance. Type 2 diabetes, obesity and PCOS are characterized by pronounced defects in the insulin-stimulated glucose uptake, in particular glycogen synthesis and to a lesser extent glucose oxidation, and the ability of insulin to suppress lipid oxidation. In inherited insulin resistance, however, only insulin action on glucose uptake and glycogen synthesis is impaired. This suggests that the defects in glucose and lipid oxidation in the common metabolic disorders are secondary to other factors. In young women with PCOS, the degree of insulin resistance was similar to that seen in middle-aged patients with type 2 diabetes. This supports the hypothesis of an unique pathogenesis of insulin resistance in PCOS. Insulin in physiological concentrations stimulates glucose uptake in human skeletal

  10. Combined contributions of over-secreted glucagon-like peptide 1 and suppressed insulin secretion to hyperglycemia induced by gatifloxacin in rats

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yunli, E-mail: chrisyu1255@yahoo.com.cn [Department of Pharmaceutics, The Second Affiliated Hospital of Soochow University, Suzhou 215004 (China); Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009 (China); Wang, Xinting, E-mail: wxinting1986@yahoo.com.cn [Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009 (China); Liu, Can, E-mail: ltsan@163.com [Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009 (China); Yao, Dan, E-mail: erinyao@126.com [Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009 (China); Shanghai Institute of Materia Medica, Shanghai 201203 (China); Hu, Mengyue, E-mail: juliahmy@126.com [Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009 (China); Li, Jia, E-mail: ljbzd@163.com [Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009 (China); Hu, Nan, E-mail: hn_324@163.com [Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009 (China); Liu, Li, E-mail: liulee@cpu.edu.cn [Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009 (China); Liu, Xiaodong, E-mail: xdliu@cpu.edu.cn [Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009 (China)

    2013-02-01

    Accumulating evidences have showed that gatifloxacin causes dysglycemia in both diabetic and non-diabetic patients. Our preliminary study demonstrated that gatifloxacin stimulated glucagon-like peptide 1 (GLP-1) secretion from intestinal cells. The aim of the study was to investigate the association between gatifloxacin-stimulated GLP-1 release and dysglycemia in both normal and streptozotocin-induced diabetic rats and explore the possible mechanisms. Oral administration of gatifloxacin (100 mg/kg/day and 200 mg/kg/day) for 3 and 12 days led to marked elevation of GLP-1 levels, accompanied by significant decrease in insulin levels and increase in plasma glucose. Similar results were found in normal rats treated with 3-day gatifloxacin. Gatifloxacin-stimulated GLP-1 release was further confirmed in NCI-H716 cells, which was abolished by diazoxide, a K{sub ATP} channel opener. QT-PCR analysis showed that gatifloxacin also upregulated expression of proglucagon and prohormone convertase 3 mRNA. To clarify the contradiction on elevated GLP-1 without insulinotropic effect, effects of GLP-1 and gatifloxacin on insulin release were investigated using INS-1 cells. We found that short exposure (2 h) to GLP-1 stimulated insulin secretion and biosynthesis, whereas long exposure (24 h and 48 h) to high level of GLP-1 inhibited insulin secretion and biosynthesis. Moreover, we also confirmed gatifloxacin acutely stimulated insulin secretion while chronically inhibited insulin biosynthesis. All the results gave an inference that gatifloxacin stimulated over-secretion of GLP-1, in turn, high levels of GLP-1 and gatifloxacin synergistically impaired insulin release, worsening hyperglycemia. -- Highlights: ► Gatifloxacin induced hyperglycemia both in diabetic rats and normal rats. ► Gatifloxacin enhanced GLP-1 secretion but inhibited insulin secretion in rats. ► Long-term exposure to high GLP-1 inhibited insulin secretion and biosynthesis. ► GLP-1 over-secretion may be

  11. Combined contributions of over-secreted glucagon-like peptide 1 and suppressed insulin secretion to hyperglycemia induced by gatifloxacin in rats

    International Nuclear Information System (INIS)

    Yu, Yunli; Wang, Xinting; Liu, Can; Yao, Dan; Hu, Mengyue; Li, Jia; Hu, Nan; Liu, Li; Liu, Xiaodong

    2013-01-01

    Accumulating evidences have showed that gatifloxacin causes dysglycemia in both diabetic and non-diabetic patients. Our preliminary study demonstrated that gatifloxacin stimulated glucagon-like peptide 1 (GLP-1) secretion from intestinal cells. The aim of the study was to investigate the association between gatifloxacin-stimulated GLP-1 release and dysglycemia in both normal and streptozotocin-induced diabetic rats and explore the possible mechanisms. Oral administration of gatifloxacin (100 mg/kg/day and 200 mg/kg/day) for 3 and 12 days led to marked elevation of GLP-1 levels, accompanied by significant decrease in insulin levels and increase in plasma glucose. Similar results were found in normal rats treated with 3-day gatifloxacin. Gatifloxacin-stimulated GLP-1 release was further confirmed in NCI-H716 cells, which was abolished by diazoxide, a K ATP channel opener. QT-PCR analysis showed that gatifloxacin also upregulated expression of proglucagon and prohormone convertase 3 mRNA. To clarify the contradiction on elevated GLP-1 without insulinotropic effect, effects of GLP-1 and gatifloxacin on insulin release were investigated using INS-1 cells. We found that short exposure (2 h) to GLP-1 stimulated insulin secretion and biosynthesis, whereas long exposure (24 h and 48 h) to high level of GLP-1 inhibited insulin secretion and biosynthesis. Moreover, we also confirmed gatifloxacin acutely stimulated insulin secretion while chronically inhibited insulin biosynthesis. All the results gave an inference that gatifloxacin stimulated over-secretion of GLP-1, in turn, high levels of GLP-1 and gatifloxacin synergistically impaired insulin release, worsening hyperglycemia. -- Highlights: ► Gatifloxacin induced hyperglycemia both in diabetic rats and normal rats. ► Gatifloxacin enhanced GLP-1 secretion but inhibited insulin secretion in rats. ► Long-term exposure to high GLP-1 inhibited insulin secretion and biosynthesis. ► GLP-1 over-secretion may be involved in

  12. Integrating Mechanisms for Insulin Resistance: Common Threads and Missing Links

    Science.gov (United States)

    Samuel, Varman T.; Shulman, Gerald I.

    2012-01-01

    Insulin resistance is a complex metabolic disorder that defies a single etiological pathway. Accumulation of ectopic lipid metabolites, activation of the unfolded protein response (UPR) pathway and innate immune pathways have all been implicated in the pathogenesis of insulin resistance. However, these pathways are also closely linked to changes in fatty acid uptake, lipogenesis, and energy expenditure that can impact ectopic lipid deposition. Ultimately, accumulation of specific lipid metabolites (diacylglycerols and/or ceramides) in liver and skeletal muscle, may be a common pathway leading to impaired insulin signaling and insulin resistance. PMID:22385956

  13. Insulin resistance and atherosclerosis : the role of visceral fat

    NARCIS (Netherlands)

    Gast, K.B.

    2016-01-01

    The main objective of this thesis was to unravel relationships between obesity, insulin resistance, hyperglycemia, and atherosclerosis. It is well-established that patients with type 2 diabetes have a 2- to 3-fold increased risk of cardiovascular disease. We investigated whether insulin resistance

  14. Method for preventing and/or treating insulin resistance

    NARCIS (Netherlands)

    Nieuwdorp, M.; Vos, de W.M.

    2013-01-01

    The present invention describes use of Eubacterium hallii et rel. and/or Alcaligenes faecalis et rel., as well as pharmaceutical, food, or feed compositions comprising these bacteria, as a medicament, in particular for preventing and/or treating insulin resistance and/or insulin resistance-related

  15. Whole-Body and Hepatic Insulin Resistance in Obese Children

    Science.gov (United States)

    Ibarra-Reynoso, Lorena del Rocío; Pisarchyk, Liudmila; Pérez-Luque, Elva Leticia; Garay-Sevilla, Ma. Eugenia; Malacara, Juan Manuel

    2014-01-01

    Background Insulin resistance may be assessed as whole body or hepatic. Objective To study factors associated with both types of insulin resistance. Methods Cross-sectional study of 182 obese children. Somatometric measurements were registered, and the following three adiposity indexes were compared: BMI, waist-to-height ratio and visceral adiposity. Whole-body insulin resistance was evaluated using HOMA-IR, with 2.5 as the cut-off point. Hepatic insulin resistance was considered for IGFBP-1 level quartiles 1 to 3 (HOMA-IR was negatively associated with IGFBP-1 and positively associated with BMI, triglycerides, leptin and mother's BMI. Girls had increased HOMA-IR. IGFBP-1 was negatively associated with waist-to-height ratio, age, leptin, HOMA-IR and IGF-I. We did not find HOMA-IR or IGFBP-1 associated with fatty liver. Conclusion In school-aged children, BMI is the best metric to predict whole-body insulin resistance, and waist-to-height ratio is the best predictor of hepatic insulin resistance, indicating that central obesity is important for hepatic insulin resistance. The reciprocal negative association of IGFBP-1 and HOMA-IR may represent a strong interaction of the physiological processes of both whole-body and hepatic insulin resistance. PMID:25411786

  16. Blood-based biomarkers of age-associated epigenetic changes in human islets associate with insulin secretion and diabetes

    DEFF Research Database (Denmark)

    Bacos, Karl; Gillberg, Linn; Volkov, Petr

    2016-01-01

    identified in human islets (for example, KLF14, FHL2, ZNF518B and FAM123C) and some associate with insulin secretion and T2D. DNA methylation correlates with islet expression of multiple genes, including FHL2, ZNF518B, GNPNAT1 and HLTF. Silencing these genes in β-cells alter insulin secretion. Together, we...

  17. Relationship between insulin resistance and tissue blood flow in preeclampsia.

    Science.gov (United States)

    Anim-Nyame, Nick; Gamble, John; Sooranna, Suren R; Johnson, Mark R; Steer, Philip J

    2015-05-01

    Preeclampsia is characterized by generalized endothelial dysfunction and impaired maternal tissue perfusion, and insulin resistance is a prominent feature of this disease. The aim of this study was to test the hypothesis that insulin resistance in preeclampsia is related to the reduced resting tissue blood flow. We used venous occlusion plethysmography to compare the resting calf muscle blood flow (measured as QaU) in 20 nulliparous women with preeclampsia and 20 normal pregnant controls matched for maternal age, gestational age, parity and BMI during the third trimester. Fasting blood samples were obtained to measure the plasma concentrations of insulin and glucose, and to calculate the fasting insulin resistance index (FIRI), a measure of insulin resistance in both groups of women. Calf blood flow was significantly reduced in the preeclampsia group (1.93 ± 0.86 QaU), compared with normal pregnant controls (3.94 ± 1.1 QaU, P insulin concentrations and Insulin Resistance Index were significantly higher in preeclampsia compared with normal pregnancy (P insulin concentrations (r = -0.57, P = 0.008) and FIRI (r = -0.59, P = 0.006) in preeclampsia, but not in normal pregnancy. These findings support our hypothesis and raise the possibility that reduced tissue blood flow may a play a role in the increased insulin resistance seen in preeclampsia.

  18. Nicotinamide induces differentiation of embryonic stem cells into insulin-secreting cells

    International Nuclear Information System (INIS)

    Vaca, Pilar; Berna, Genoveva; Araujo, Raquel; Carneiro, Everardo M.; Bedoya, Francisco J.; Soria, Bernat; Martin, Franz

    2008-01-01

    The poly(ADP-ribose) polymerase (PARP) inhibitor, nicotinamide, induces differentiation and maturation of fetal pancreatic cells. In addition, we have previously reported evidence that nicotinamide increases the insulin content of cells differentiated from embryonic stem (ES) cells, but the possibility of nicotinamide acting as a differentiating agent on its own has never been completely explored. Islet cell differentiation was studied by: (i) X-gal staining after neomycin selection; (ii) BrdU studies; (iii) single and double immunohistochemistry for insulin, C-peptide and Glut-2; (iv) insulin and C-peptide content and secretion assays; and (v) transplantation of differentiated cells, under the kidney capsule, into streptozotocin (STZ)-diabetic mice. Here we show that undifferentiated mouse ES cells treated with nicotinamide: (i) showed an 80% decrease in cell proliferation; (ii) co-expressed insulin, C-peptide and Glut-2; (iii) had values of insulin and C-peptide corresponding to 10% of normal mouse islets; (iv) released insulin and C-peptide in response to stimulatory glucose concentrations; and (v) after transplantation into diabetic mice, normalized blood glucose levels over 7 weeks. Our data indicate that nicotinamide decreases ES cell proliferation and induces differentiation into insulin-secreting cells. Both aspects are very important when thinking about cell therapy for the treatment of diabetes based on ES cells

  19. Brain natriuretic peptide and insulin resistance in older adults.

    Science.gov (United States)

    Kim, F; Biggs, M L; Kizer, J R; Brutsaert, E F; de Filippi, C; Newman, A B; Kronmal, R A; Tracy, R P; Gottdiener, J S; Djoussé, L; de Boer, I H; Psaty, B M; Siscovick, D S; Mukamal, K J

    2017-02-01

    Higher levels of brain natriuretic peptide (BNP) have been associated with a decreased risk of diabetes in adults, but whether BNP is related to insulin resistance in older adults has not been established. N-terminal of the pro hormone brain natriuretic peptide (NT-pro BNP) was measured among Cardiovascular Health Study participants at the 1989-1990, 1992-1993 and 1996-1997 examinations. We calculated measures of insulin resistance [homeostatic model assessment of insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), Gutt index, Matsuda index] from fasting and 2-h concentrations of glucose and insulin among 3318 individuals with at least one measure of NT-proBNP and free of heart failure, coronary heart disease and chronic kidney disease, and not taking diabetes medication. We used generalized estimating equations to assess the cross-sectional association of NT-proBNP with measures of insulin resistance. Instrumental variable analysis with an allele score derived from nine genetic variants (single nucleotide polymorphisms) within or near the NPPA and NPPB loci was used to estimate an un-confounded association of NT-proBNP levels on insulin resistance. Lower NT-proBNP levels were associated with higher insulin resistance even after adjustment for BMI, waist circumference and other risk factors (P insulin resistance (P = 0.38; P = 0.01 for comparison with the association of measured levels of NT-proBNP). In older adults, lower NT-proBNP is associated with higher insulin resistance, even after adjustment for traditional risk factors. Because related genetic variants were not associated with insulin resistance, the causal nature of this association will require future study. © 2016 Diabetes UK.

  20. Plasma kisspeptin levels are associated with insulin secretion in nondiabetic individuals.

    Directory of Open Access Journals (Sweden)

    Francesco Andreozzi

    Full Text Available To evaluate if plasma kisspeptin concentrations are associated with insulin secretion, as suggested by recent in vitro studies, independently of confounders. 261 nondiabetic subjects were stratified into tertiles according to kisspeptin values. Insulin secretion was assessed using indexes derived from oral glucose tolerance test (OGTT. After adjusting for age, gender, and BMI, subjects in the highest (tertile 3 kisspeptin group exhibited significantly lower values of insulinogenic index, corrected insulin response (CIR30, and Stumvoll indexes for first-phase and second-phase insulin release as compared with low (tertile 1 or intermediate (tertile 2 kisspeptin groups. Univariate correlations between kisspeptin concentration and metabolic variables showed that kisspeptin concentration was significantly and positively correlated with age, blood pressure, and 2-h post-load glucose, and inversely correlated with BMI, and waist circumference. There was an inverse relationship between kisspeptin levels and OGTT-derived indexes of glucose-stimulated insulin secretion. A multivariable regression analysis in a model including all the variables significantly correlated with kisspeptin concentration showed thar age (β = -0.338, P<0.0001, BMI (β = 0.272, P<0.0001, 2-h post-load glucose (β = -0.229, P<0.0001, and kisspeptin (β = -0.105, P = 0.03 remained associated with insulinogenic index. These factors explained 34.6% of the variance of the insulinogenic index. In conclusion, kisspeptin concentrations are associated with insulin secretion independently of important determinants of glucose homeostasis such as gender, age, adiposity, 2-h post-load glucose, and insulin sensitivity.

  1. Detecting insulin resistance in polycystic ovary syndrome: purposes and pitfalls.

    Science.gov (United States)

    Legro, Richard S; Castracane, V Daniel; Kauffman, Robert P

    2004-02-01

    Approximately 50% to 70% of all women with polycystic ovary syndrome (PCOS) have some degree of insulin resistance, and this hormone insensitivity probably contributes to the hyperandrogenism that is responsible for the signs and symptoms of PCOS. Although uncertainty exists, early detection and treatment of insulin resistance in this population could ultimately reduce the incidence or severity of diabetes mellitus, dyslipidemia, hypertension, and cardiovascular disease. Even if that proves to be the case, there are still several problems with our current approach to insulin sensitivity assessment in PCOS, including the apparent lack of consensus on what defines PCOS and "normal" insulin sensitivity, ethnic and genetic variability, the presence of other factors contributing to insulin resistance such as obesity, stress, and aging, and concern about whether simplified models of insulin sensitivity have the precision to predict treatment needs, responses, and future morbidity. Although the hyperinsulinemic-euglycemic clamp technique is the gold standard for measuring insulin sensitivity, it is too expensive, time-consuming, and labor-intensive to be of practical use in an office setting. Homeostatic measurements (fasting glucose/insulin ratio or homeostatic model assessment [HOMA] value) and minimal model tests (particularly the oral glucose tolerance test [OGTT]) represent the easiest office-based assessments of insulin resistance in the PCOS patient. The OGTT is probably the best simple, office-based method to assess women with PCOS because it provides information about both insulin resistance and glucose intolerance. The diagnosis of glucose intolerance holds greater prognostic and treatment implications. All obese women with PCOS should be screened for the presence of insulin resistance by looking for other stigmata of the insulin resistance syndrome such as hypertension, dyslipidemia, central obesity, and glucose intolerance.

  2. Familial short fifth metacarpals and insulin resistance

    International Nuclear Information System (INIS)

    Hyari, Muwafag; Hamamy, Hanan; Barham, Muries; Ajlouni, Kamel; Al-Hadidy, Azmy

    2006-01-01

    Very few reports on the phenotype of short fifth metacarpals have been published in the medical literature. We report a Jordanian family in which three sisters aged 15, 13 and 8 years revealed bilateral shortening of the fifth fingers and radiological shortening of the fifth metacarpals. The father had unilateral short fifth metacarpal. The elder two sisters, their father as well as their brother and another sister manifested insulin resistance. Spherocytosis was diagnosed in one of the girls and her father. The parents are non-consanguineous. This constellation of findings has not been previously reported and could point to the presence of two disorders segregating in the family or to a novel syndrome with autosomal dominant inheritance and variable expressivity. (orig.)

  3. Insulin resistance in human subjects having impaired glucose regulation

    International Nuclear Information System (INIS)

    Khan, S.H.; Khan, F.A.; Ijaz, A.

    2007-01-01

    To determine insulin resistance in human subjects having impaired glucose regulation (IGR) by Homeostasis Model Assessment for Insulin Resistance (HOMA-IR). A total of 100 subjects with impaired glucose regulation were selected for evaluation of metabolic syndrome as per the criteria of National Cholesterol Education Program, Adult Treatment Panel III (NCEP, ATP III), along with 47 healthy age and gender-matched controls. Physical examination to determine blood pressure and waist circumference was carried out and so was sampling for plasma glucose, serum triglycerides, HDL-cholesterol and insulin. Insulin resistance was calculated by the HOMA-IR. Finally, subjects with and without metabolic syndrome were compared with controls (n=47), using one-way ANOVA for studying insulin resistance between groups, with Tukey's post-hoc comparison. The frequency of finding metabolic syndrome in cases of IGR remained 47%. The insulin resistance demonstrated stepwise worsening from control population (mean=1.54, 95 % CI: 1.77 - 2.37) to subjects suffering from only IGR (mean=2.07, 95 % CI: 1.77- 2.37) to metabolic syndrome (mean=2.67, 95 %, CI: 2.34 - 3.00) (p < 0.001). Patients with impaired glucose regulation may have significant insulin resistance. It is, thus, recommended that a vigorous search be made to measure insulin resistance in all cases diagnosed to have impaired glucose regulation. (author)

  4. Dietary fat and insulin resistance: a connection through leptin and PPARγ activation

    Directory of Open Access Journals (Sweden)

    Doaa Nader Al-Jada

    2016-06-01

    Full Text Available Insulin resistance refers to reduced insulin action in peripheral tissues and impaired suppression of endogenous glucose production, a state which is critical for maintaining normal glucose homeostasis. Insulin resistance is partly explained by genetic factors and is strongly influenced by the individual's habitual lifestyle. Investigating factors that may influence the development of insulin resistance and their mechanisms of action is highly significant; one of these factors include dietary fat. Both quantitative and qualitative terms of dietary fat have been known to play an important role in the development of insulin resistance, although the mechanism underlying this effect is not fully understood. In this regard, the classical view has been that dietary fat quality mainly affects cell membrane fatty acid composition and consequently the membrane function. Recently, the relationship between dietary fat and insulin resistance has entered an advanced level due to the discovery that different fatty acids can regulate gene expression, transcriptional activity and adipocytokines secretion. In essence, this provides new mechanisms by which fatty acids exert their cellular effects. The present review critically assesses the effect of dietary fat quality on the development of insulin resistance in relation to the adipocytokine, leptin and the activation of the transcription factor, peroxisome proliferator-activated receptor gamma (PPARγ. It is evident that fat quality influences the development of insulin resistance and has a more important role than quantity. Leptin and PPARγ prove to be potential candidates linking dietary fat with insulin resistance. However, the exact role or mechanism of action of various types of dietary fat in the development of insulin resistance is still uncertain. Further well-controlled studies in humans are necessary to establish better evidence-based dietary fat recommendations for diabetes prevention and its

  5. Crif1 Deficiency Reduces Adipose OXPHOS Capacity and Triggers Inflammation and Insulin Resistance in Mice

    Science.gov (United States)

    Ryu, Min Jeong; Kim, Soung Jung; Kim, Yong Kyung; Choi, Min Jeong; Tadi, Surendar; Lee, Min Hee; Lee, Seong Eun; Chung, Hyo Kyun; Jung, Saet Byel; Kim, Hyun-Jin; Jo, Young Suk; Kim, Koon Soon; Lee, Sang-Hee; Kim, Jin Man; Kweon, Gi Ryang; Park, Ki Cheol; Lee, Jung Uee; Kong, Young Yun; Lee, Chul-Ho; Chung, Jongkyeong; Shong, Minho

    2013-01-01

    Impaired mitochondrial oxidative phosphorylation (OXPHOS) has been proposed as an etiological mechanism underlying insulin resistance. However, the initiating organ of OXPHOS dysfunction during the development of systemic insulin resistance has yet to be identified. To determine whether adipose OXPHOS deficiency plays an etiological role in systemic insulin resistance, the metabolic phenotype of mice with OXPHOS–deficient adipose tissue was examined. Crif1 is a protein required for the intramitochondrial production of mtDNA–encoded OXPHOS subunits; therefore, Crif1 haploinsufficient deficiency in mice results in a mild, but specific, failure of OXPHOS capacity in vivo. Although adipose-specific Crif1-haploinsufficient mice showed normal growth and development, they became insulin-resistant. Crif1-silenced adipocytes showed higher expression of chemokines, the expression of which is dependent upon stress kinases and antioxidant. Accordingly, examination of adipose tissue from Crif1-haploinsufficient mice revealed increased secretion of MCP1 and TNFα, as well as marked infiltration by macrophages. These findings indicate that the OXPHOS status of adipose tissue determines its metabolic and inflammatory responses, and may cause systemic inflammation and insulin resistance. PMID:23516375

  6. Targeting development of incretin-producing cells increases insulin secretion

    DEFF Research Database (Denmark)

    Petersen, Natalia; Reimann, Frank; van Es, Johan H

    2015-01-01

    the number of intestinal L cells, which produce GLP-1, is an alternative strategy to augment insulin responses and improve glucose tolerance. Blocking the NOTCH signaling pathway with the γ-secretase inhibitor dibenzazepine increased the number of L cells in intestinal organoid-based mouse and human culture...... of the development of incretin-producing cells in the intestine has potential as a therapeutic strategy to improve glycemic control....

  7. The influence of GLP-1 on glucose-stimulated insulin secretion

    DEFF Research Database (Denmark)

    Kjems, Lise L; Holst, Jens Juul; Vølund, Aage

    2003-01-01

    . However, the dose-response relationship between GLP-1 and basal and glucose-stimulated prehepatic insulin secretion rate (ISR) is currently not known. Seven patients with type 2 diabetes and seven matched nondiabetic control subjects were studied. ISR was determined during a graded glucose infusion of 2...

  8. High passage MIN6 cells have impaired insulin secretion with impaired glucose and lipid oxidation.

    Directory of Open Access Journals (Sweden)

    Kim Cheng

    Full Text Available Type 2 diabetes is a metabolic disorder characterized by the inability of beta-cells to secrete enough insulin to maintain glucose homeostasis. MIN6 cells secrete insulin in response to glucose and other secretagogues, but high passage (HP MIN6 cells lose their ability to secrete insulin in response to glucose. We hypothesized that metabolism of glucose and lipids were defective in HP MIN6 cells causing impaired glucose stimulated insulin secretion (GSIS. HP MIN6 cells had no first phase and impaired second phase GSIS indicative of global functional impairment. This was coupled with a markedly reduced ATP content at basal and glucose stimulated states. Glucose uptake and oxidation were higher at basal glucose but ATP content failed to increase with glucose. HP MIN6 cells had decreased basal lipid oxidation. This was accompanied by reduced expressions of Glut1, Gck, Pfk, Srebp1c, Ucp2, Sirt3, Nampt. MIN6 cells represent an important model of beta cells which, as passage numbers increased lost first phase but retained partial second phase GSIS, similar to patients early in type 2 diabetes onset. We believe a number of gene expression changes occurred to produce this defect, with emphasis on Sirt3 and Nampt, two genes that have been implicated in maintenance of glucose homeostasis.

  9. Insulin Sensitivity Determines Effects of Insulin and Meal Ingestion on Systemic Vascular Resistance in Healthy Subjects.

    Science.gov (United States)

    Woerdeman, Jorn; Meijer, Rick I; Eringa, Etto C; Hoekstra, Trynke; Smulders, Yvo M; Serné, Erik H

    2016-01-01

    In addition to insulin's metabolic actions, insulin can dilate arterioles which increase blood flow to metabolically active tissues. This effect is blunted in insulin-resistant subjects. Insulin's effect on SVR, determined by resistance arterioles, has, however, rarely been examined directly. We determined the effects of both hyperinsulinemia and a mixed meal on SVR and its relationship with insulin sensitivity. Thirty-seven lean and obese women underwent a hyperinsulinemic-euglycemic clamp, and 24 obese volunteers underwent a mixed-meal test. SVR was assessed using CPP before and during hyperinsulinemia as well as before and 60 and 120 minutes after a meal. SVR decreased significantly during hyperinsulinemia (-13%; p Insulin decreased SVR more strongly in insulin-sensitive individuals (standardized β: -0.44; p = 0.01). In addition, SVR at 60 minutes after meal ingestion was inversely related to the Matsuda index (β: -0.39; p = 0.04) and the change in postprandial SVR was directly related to postprandial glycemia (β: 0.53; p insulin resistance. This suggests that resistance to insulin-induced vasodilatation contributes to regulation of vascular resistance. © 2015 John Wiley & Sons Ltd.

  10. Relationship between insulin resistance and plasma endothelin in hypertension patients

    International Nuclear Information System (INIS)

    Duan Yongqiang; Wang Zuobing; Yu Hui; Cao Wei; Wang Jing; Li Xiaoqin

    2011-01-01

    To explore the relationship between plasma endothelin and hypertension insulin resistance, and the improvement of insulin resistance in hypertension patients treated with captopril and l-amlodipine, 25 patients with primary hypertension and impaired glucose tolerance were selected and treated by captopril and l-amlodipine. Systolic pressure, diastolic pressure, fasting blood glucose, insulin and insulin antibody were measured before and after treatment and compared with healthy controls. The results showed that the plasma ET-1 level in hypertension group was significantly higher than that of healthy controls (P<0.01), and he plasma ET-1 level was positively correlated with FPG, FINS, Anti-INS, HOMA-IR. The systolic pressure, diastolic pressure, fasting blood glucose, insulin, insulin antibody and insulin resistance index in hypertension patients were decreased significantly after treatment (P<0.05). There is a good correlation between endothelin and insulin resistance index in hypertension patients. Captopril and l-amlodipine had obvious improvement effect on insulin resistance in hypertension patients. (authors)

  11. Circulating Glucagon 1-61 Regulates Blood Glucose by Increasing Insulin Secretion and Hepatic Glucose Production

    Directory of Open Access Journals (Sweden)

    Nicolai J. Wewer Albrechtsen

    2017-11-01

    Full Text Available Glucagon is secreted from pancreatic α cells, and hypersecretion (hyperglucagonemia contributes to diabetic hyperglycemia. Molecular heterogeneity in hyperglucagonemia is poorly investigated. By screening human plasma using high-resolution-proteomics, we identified several glucagon variants, among which proglucagon 1-61 (PG 1-61 appears to be the most abundant form. PG 1-61 is secreted in subjects with obesity, both before and after gastric bypass surgery, with protein and fat as the main drivers for secretion before surgery, but glucose after. Studies in hepatocytes and in β cells demonstrated that PG 1-61 dose-dependently increases levels of cAMP, through the glucagon receptor, and increases insulin secretion and protein levels of enzymes regulating glycogenolysis and gluconeogenesis. In rats, PG 1-61 increases blood glucose and plasma insulin and decreases plasma levels of amino acids in vivo. We conclude that glucagon variants, such as PG 1-61, may contribute to glucose regulation by stimulating hepatic glucose production and insulin secretion.

  12. Factors influencing insulin and glucagon secretion in lean and genetically obese mice

    International Nuclear Information System (INIS)

    Beloff-Chain, A.; Newman, M.E.; Mansford, K.R.L.

    1977-01-01

    The control of 125 I-labelled insulin and glucagon secretion from isolated pancreatic islets of lean and genetically obese mice has been compared. The enlarged islets of obese mouse pancreas and islets of obese mice maintained on a restricted diet manifested a greater response to glucose stimulation of insulin secretion than the lean mice islets. The glucagon content of the islets, the secretion of glucagon in a medium containing 150 mg% glucose and the stimulation of glucagon secretion by arginine did not differ significantly in the two groups. Adrenaline stimulated glucagon secretion in vitro from obese mice but not from lean mice. Antiinsulin serum injections into obese mice increased the plasma glucagon levels about twofold and had no effect on glucagon levels in lean mice, although the level of hyperglycaemia was the same in both groups. It is suggested that the suppression of glucagon release by glucose requires a higher concentration of insulin in the obese mouse pancreas than in lean mice. (orig./AJ) [de

  13. Factors influencing insulin and glucagon secretion in lean and genetically obese mice

    Energy Technology Data Exchange (ETDEWEB)

    Beloff-Chain, A; Newman, M E; Mansford, K R.L. [Imperial Coll. of Science and Technology, London (UK). Dept. of Biochemistry

    1977-01-01

    The control of /sup 125/I-labelled insulin and glucagon secretion from isolated pancreatic islets of lean and genetically obese mice has been compared. The enlarged islets of obese mouse pancreas and islets of obese mice maintained on a restricted diet manifested a greater response to glucose stimulation of insulin secretion than the lean mice islets. The glucagon content of the islets, the secretion of glucagon in a medium containing 150 mg% glucose and the stimulation of glucagon secretion by arginine did not differ significantly in the two groups. Adrenaline stimulated glucagon secretion in vitro from obese mice but not from lean mice. Antiinsulin serum injections into obese mice increased the plasma glucagon levels about twofold and had no effect on glucagon levels in lean mice, although the level of hyperglycaemia was the same in both groups. It is suggested that the suppression of glucagon release by glucose requires a higher concentration of insulin in the obese mouse pancreas than in lean mice.

  14. Intake of Lactobacillus reuteri Improves Incretin and Insulin Secretion in Glucose-Tolerant Humans

    DEFF Research Database (Denmark)

    Simon, Marie-Christine; Strassburger, Klaus; Nowotny, Bettina

    2015-01-01

    production. Muscle and hepatic lipid contents were assessed by (1)H-magnetic resonance spectroscopy, and immune status, cytokines, and endotoxin were measured with specific assays. RESULTS: In glucose-tolerant volunteers, daily administration of L. reuteri SD5865 increased glucose-stimulated GLP-1 and GLP-2....... reuteri SD5865 or placebo over 4 weeks. Oral glucose tolerance and isoglycemic glucose infusion tests were used to assess incretin effect and GLP-1 and GLP-2 secretion, and euglycemic-hyperinsulinemic clamps with [6,6-(2)H2]glucose were used to measure peripheral insulin sensitivity and endogenous glucose...... cytokines. CONCLUSIONS: Enrichment of gut microbiota with L. reuteri increases insulin secretion, possibly due to augmented incretin release, but does not directly affect insulin sensitivity or body fat distribution. This suggests that oral ingestion of one specific strain may serve as a novel therapeutic...

  15. Redifferentiation of insulin-secreting cells after in vitro expansion of adult human pancreatic islet tissue

    International Nuclear Information System (INIS)

    Lechner, Andreas; Nolan, Anna L.; Blacken, Robyn A.; Habener, Joel F.

    2005-01-01

    Cellular replacement therapy holds promise for the treatment of diabetes mellitus but donor tissue is severely limited. Therefore, we investigated whether insulin-secreting cells could be differentiated in vitro from a monolayer of cells expanded from human donor pancreatic islets. We describe a three-step culture protocol that allows for the efficient generation of insulin-producing cell clusters from in vitro expanded, hormone-negative cells. These clusters express insulin at levels of up to 34% that of average freshly isolated human islets and secrete C-peptide upon membrane depolarization. They also contain cells expressing the other major islet hormones (glucagon, somatostatin, and pancreatic polypeptide). The source of the newly differentiated endocrine cells could either be indigenous stem/progenitor cells or the proliferation-associated dedifferentiation and subsequent redifferentiation of mature endocrine cells. The in vitro generated cell clusters may be efficacious in providing islet-like tissue for transplantation into diabetic recipients

  16. Postreceptor defects causing insulin resistance in normoinsulinemic non-insulin-dependent diabetes mellitus

    International Nuclear Information System (INIS)

    Bolinder, J.; Ostman, J.; Arner, P.

    1982-01-01

    The mechanisms of the diminished hypoglycemic response to insulin in non-insulin-dependent diabetes mellitus (NIDDM) with normal levels of circulating plasma insulin were investigated. Specific binding of mono- 125 I (Tyr A14)-insulin to isolated adipocytes and effects of insulin (5--10,000 microunits/ml) on glucose oxidation and lipolysis were determined simultaneously in subcutaneous adipose tissue of seven healthy subjects of normal weight and seven untreated NIDDM patients with normal plasma insulin levels. The two groups were matched for age, sex, and body weight. Insulin binding, measured in terms of receptor number and affinity, was normal in NIDDM, the total number of receptors averaging 350,000 per cell. Neither sensitivity nor the maximum antilipolytic effect of insulin was altered in NIDDM patients as compared with control subjects; the insulin concentration producing half the maximum effect (ED50) was 10 microunits/ml. As regards the effect of insulin on glucose oxidation, for the control subjects ED50 was 30 microunits/ml, whereas in NIDDM patients, insulin exerted no stimulatory effect. The results obtained suggest that the effect of insulin on glucose utilization in normoinsulinemic NIDDM may be diminished in spite of normal insulin binding to receptors. The resistance may be due solely to postreceptor defects, and does not involve antilipolysis

  17. Insulin resistance and mitochondrial function in skeletal muscle

    DEFF Research Database (Denmark)

    Dela, Flemming; Helge, Jørn Wulff

    2013-01-01

    are used in the attempt to resolve the mechanisms of insulin resistance. In this context, a dysfunction of mitochondria in the skeletal muscle has been suggested to play a pivotal role. It has been postulated that a decrease in the content of mitochondria in the skeletal muscle can explain the insulin...... resistance. Complementary to this also specific defects of components in the respiratory chain in the mitochondria have been suggested to play a role in insulin resistance. A key element in these mechanistic suggestions is inability to handle substrate fluxes and subsequently an accumulation of ectopic...... intramyocellular lipids, interfering with insulin signaling. In this review we will present the prevailing view-points and argue for the unlikelihood of this scenario being instrumental in human insulin resistance. This article is part of a Directed Issue entitled: Bioenergetic dysfunction....

  18. Persistent Organic Pollutant Exposure Leads to Insulin Resistance Syndrome

    DEFF Research Database (Denmark)

    Ruzzin, Jérôme; Petersen, Rasmus; Meugnier, Emmanuelle

    2010-01-01

    BACKGROUND: The incidence of the insulin resistance syndrome has increased at an alarming rate worldwide creating a serious challenge to public health care in the 21st century. Recently, epidemiological studies have associated the prevalence of type 2 diabetes with elevated body burdens...... of persistent organic pollutants (POPs). However, experimental evidence demonstrating a causal link between POPs and the development of insulin resistance is lacking. OBJECTIVE: We investigated whether exposure to POPs contributes to insulin resistance and metabolic disorders. METHODS: Wistar rats were exposed...... salmon oil. We measured body weight, whole-body insulin sensitivity, POP accumulation, lipid and glucose homeostasis, gene expression and performed microarray analysis. RESULTS: Adult male rats exposed to crude, but not refined, salmon oil developed insulin resistance, abdominal obesity...

  19. Higher fetal insulin resistance in Chinese pregnant women with gestational diabetes mellitus and correlation with maternal insulin resistance.

    Science.gov (United States)

    Wang, Qiuwei; Huang, Ruiping; Yu, Bin; Cao, Fang; Wang, Huiyan; Zhang, Ming; Wang, Xinhong; Zhang, Bin; Zhou, Hong; Zhu, Ziqiang

    2013-01-01

    The aim of this study was to determine the effect of gestational diabetes mellitus (GDM) on fetal insulin resistance or β-cell function in Chinese pregnant women with GDM. Maternal fasting blood and venous cord blood samples (reflecting fetal condition) were collected in 65 well-controlled Chinese GDM mothers (only given dietary intervention) and 83 control subjects. The insulin, glucose and proinsulin concentrations of both maternal and cord blood samples were measured, and the homeostasis model assessment of insulin resistance (HOMA-IR) and the proinsulin-to-insulin ratios (an indicator of fetal β-cell function) were calculated in maternal and cord blood respectively. Both maternal and fetal levels of insulin, proinsulin and HOMA-IR but not proinsulin-to-insulin ratios were significantly higher in the GDM group than in the control group (maternal insulin, 24.8 vs. 15.4 µU/mL, P = 0.004, proinsulin, 23.3 vs. 16.2 pmol/L, P = 0.005, and HOMA-IR, 5.5 vs. 3.5, P = 0.041, respectively; fetal: insulin, 15.1 vs. 7.9 µU/mL, Pinsulin ratios was significantly correlated to maternal HOMA-IR (r = 0.307, P = 0.019), in the pregnant women with GDM. Fetal insulin resistance was higher in Chinese pregnant women with GDM than control subjects, and correlated with maternal insulin resistance.

  20. BAG3 regulates formation of the SNARE complex and insulin secretion

    Science.gov (United States)

    Iorio, V; Festa, M; Rosati, A; Hahne, M; Tiberti, C; Capunzo, M; De Laurenzi, V; Turco, M C

    2015-01-01

    Insulin release in response to glucose stimulation requires exocytosis of insulin-containing granules. Glucose stimulation of beta cells leads to focal adhesion kinase (FAK) phosphorylation, which acts on the Rho family proteins (Rho, Rac and Cdc42) that direct F-actin remodeling. This process requires docking and fusion of secretory vesicles to the release sites at the plasma membrane and is a complex mechanism that is mediated by SNAREs. This transiently disrupts the F-actin barrier and allows the redistribution of the insulin-containing granules to more peripheral regions of the β cell, hence facilitating insulin secretion. In this manuscript, we show for the first time that BAG3 plays an important role in this process. We show that BAG3 downregulation results in increased insulin secretion in response to glucose stimulation and in disruption of the F-actin network. Moreover, we show that BAG3 binds to SNAP-25 and syntaxin-1, two components of the t-SNARE complex preventing the interaction between SNAP-25 and syntaxin-1. Upon glucose stimulation BAG3 is phosphorylated by FAK and dissociates from SNAP-25 allowing the formation of the SNARE complex, destabilization of the F-actin network and insulin release. PMID:25766323

  1. Insulin hypersecretion together with high luteinizing hormone concentration augments androgen secretion in oral glucose tolerance test in women with polycystic ovarian disease.

    Science.gov (United States)

    Anttila, L; Koskinen, P; Jaatinen, T A; Erkkola, R; Irjala, K; Ruutiainen, K

    1993-08-01

    Female hyperandrogenism is often associated with hyperinsulinaemia and insulin resistance. We evaluated the hormone responses in an oral glucose tolerance test to investigate the interactions of gonadotrophins, insulin, C-peptide and androgens in women with polycystic ovarian disease (PCOD). In 28 patients with ultrasonographically diagnosed PCOD, hyperinsulinaemia and insulin resistance were mainly associated with obesity. Both basal and cumulative sum of insulin to C-peptide ratios were high in obese subjects, suggesting decreasing hepatic removal of insulin caused by obesity. Nevertheless, in some lean PCOD women, despite normal fasting insulin concentrations, insulin hypersecretion existed. The mean concentration of testosterone decreased significantly during the oral glucose tolerance test both in PCOD and control women, and of androstenedione in the PCOD patients only. However, an increase in androgen responses was found in a subgroup of PCOD patients, who had both elevated luteinizing hormone (LH) concentrations and hyperinsulinaemic response to oral glucose. In the remaining PCOD patients an inverse correlation between LH and insulin was found. The patients with hyperinsulinaemia together with LH hypersecretion may represent a subgroup of PCOD with deranged regulation of androgen secretion.

  2. Alternative translation initiation of Caveolin-2 desensitizes insulin signaling through dephosphorylation of insulin receptor by PTP1B and causes insulin resistance.

    Science.gov (United States)

    Kwon, Hayeong; Jang, Donghwan; Choi, Moonjeong; Lee, Jaewoong; Jeong, Kyuho; Pak, Yunbae

    2018-06-01

    Insulin resistance, defined as attenuated sensitivity responding to insulin, impairs insulin action. Direct causes and molecular mechanisms of insulin resistance have thus far remained elusive. Here we show that alternative translation initiation (ATI) of Caveolin-2 (Cav-2) regulates insulin sensitivity. Cav-2β isoform yielded by ATI desensitizes insulin receptor (IR) via dephosphorylation by protein-tyrosine phosphatase 1B (PTP1B), and subsequent endocytosis and lysosomal degradation of IR, causing insulin resistance. Blockage of Cav-2 ATI protects against insulin resistance by preventing Cav-2β-PTP1B-directed IR desensitization, thereby normalizing insulin sensitivity and glucose uptake. Our findings show that Cav-2β is a negative regulator of IR signaling, and identify a mechanism causing insulin resistance through control of insulin sensitivity via Cav-2 ATI. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. In nondiabetic, human immunodeficiency virus-infected patients with lipodystrophy, hepatic insulin extraction and posthepatic insulin clearance rate are decreased in proportion to insulin resistance

    DEFF Research Database (Denmark)

    Haugaard, Steen B; Andersen, Ove; Hansen, Birgitte R

    2005-01-01

    In healthy, nondiabetic individuals with insulin resistance, fasting insulin is inversely correlated to the posthepatic insulin clearance rate (MCRi) and the hepatic insulin extraction (HEXi). We investigated whether similar early mechanisms to facilitate glucose homeostasis exist in nondiabetic...... > .1). Our data suggest that HEXi and MCRi are decreased in proportion to the degree of insulin resistance in nondiabetic HIV-infected patients with lipodystrophy....... insulin clearance rate was estimated as the ratio of posthepatic insulin appearance rate to steady-state plasma insulin concentration during a euglycemic hyperinsulinemic clamp (40 mU.m-2 .min-1). Posthepatic insulin appearance rate during the clamp was calculated, taking into account the remnant...

  4. 1,5-anhydroglucitol is associated with early-phase insulin secretion in chinese patients with newly diagnosed type 2 diabetes mellitus.

    Science.gov (United States)

    Ma, Xiaojing; Hao, Yaping; Hu, Xiang; Luo, Yuqi; Deng, Zixuan; Zhou, Jian; Bao, Yuqian; Jia, Weiping

    2015-05-01

    The goal of the present study was to explore the correlations of 1,5-anhydroglucitol (l,5-AG), glycated hemoglobin (HbA1c), and glycated albumin (GA) with insulin sensitivity and secretion. In total, 302 patients with newly diagnosed type 2 diabetes mellitus (166 men, 136 women) were enrolled in this study. The homeostasis model assessment for insulin resistance (HOMA-IR) and homeostasis model assessment for β-cell function (HOMA-β) were calculated to determine the basal insulin sensitivity and secretion. The insulinogenic index (IGI) was used to evaluate early-phase insulin secretion. 1,5-AG and GA were assayed via the enzymatic method, and HbA1c was detected by high-pressure liquid chromatography. Among all 302 subjects, the serum 1,5-AG level was 13.1±7.2 μg/mL, and the HbA1c and GA levels [median (interquartile range)] were 6.7% (6.2-7.3%) and 17.7% (16.0-19.5%), respectively. Increased 1,5-AG quartiles were accompanied by trends toward a decreased HOMA-IR and an increased HOMA-β and IGI (for all trends, P1). 1,5-AG was negatively associated with HOMA-IR (r=-0.200, P1) and positively associated with HOMA-β and IGI (r=0.210 and 0.413, respectively; both P1). 1,5-AG was independently related to HOMA-IR and HOMA-β and exhibited an independent positive association with IGI (standardized β=0.242, P1). Additionally, both HbA1c and GA were independently correlated with HOMA-IR and HOMA-β. 1,5-AG is not only correlated with basal insulin sensitivity and secretion, but also closely associated with early-phase insulin secretion in Chinese patients with newly diagnosed type 2 diabetes mellitus.

  5. Liraglutide increases FGF-21 activity and insulin sensitivity in high fat diet and adiponectin knockdown induced insulin resistance.

    Directory of Open Access Journals (Sweden)

    Mengliu Yang

    Full Text Available BACKGROUND: Liraglutide is a glucagon-like peptide-1 analogue that stimulates insulin secretion and improves β-cell function. However, it is not clear whether liraglutide achieves its glucose lowering effect only by its known effects or whether other as yet unknown mechanisms are involved. The aim of this study was to examine the effects of liraglutide on Fibroblast growth factor-21 (FGF-21 activity in High-fat diet (HFD fed ApoE(-/- mice with adiponectin (Acrp30 knockdown. METHOD: HFD-fed ApoE(-/- mice were treated with adenovirus vectors expressing shAcrp30 to produce insulin resistance. Hyperinsulinemic-euglycemic clamp studies were performed to evaluate insulin sensitivity of the mouse model. QRT-PCR and Western blot were used to measure the mRNA and protein expression of the target genes. RESULTS: The combination of HFD, ApoE deficiency, and hypoadiponectinemia resulted in an additive effect on insulin resistance. FGF-21 mRNA expressions in both liver and adipose tissues were significantly increased while FGF-21 receptor 1 (FGFR-1 and β-Klotho mRNA levels in adipose tissue, as well as FGFR-1-3 and β-Klotho mRNA levels in liver were significantly decreased in this model. Liraglutide treatment markedly improved insulin resistance and increased FGF-21 expression in liver and FGFR-3 in adipose tissue, restored β-Klotho mRNA expression in adipose tissue as well as FGFR-1-3, β-Klotho levels and phosphorylation of FGFR1 up to the levels observed in control mice in liver. Liraglutide treatment also further increased FGF-21 proteins in liver and plasma. In addition, as shown by hyperinsulinemic-euglycemic clamp, liraglutide treatment also markedly improved glucose metabolism and insulin sensitivity in these animals. CONCLUSION: These findings demonstrate an additive effect of HFD, ApoE deficiency, and adiponectin knockdown on insulin resistance and unveil that the regulation of glucose metabolism and insulin sensitivity by liraglutide may be

  6. Autophagy downregulation contributes to insulin resistance mediated injury in insulin receptor knockout podocytes in vitro

    Directory of Open Access Journals (Sweden)

    Ying Xu

    2016-04-01

    Full Text Available It is unknown whether autophagy activity is altered in insulin resistant podocytes and whether autophagy could be a therapeutic target for diabetic nephropathy (DN. Here we used shRNA transfection to knockdown the insulin receptor (IR gene in cultured human immortalized podocytes as an in vitro insulin resistant model. Autophagy related proteins LC3, Beclin, and p62 as well as nephrin, a podocyte injury marker, were assessed using western blot and immunofluorescence staining. Our results show that autophagy is suppressed when podocytes lose insulin sensitivity and that treatment of rapamycin, an mTOR specific inhibitor, could attenuate insulin resistance induced podocytes injury via autophagy activation. The present study deepens our understanding of the role of autophagy in the pathogenesis of DN.

  7. Validation of methods for measurement of insulin secretion in humans in vivo

    DEFF Research Database (Denmark)

    Kjems, L L; Christiansen, E; Vølund, A

    2000-01-01

    To detect and understand the changes in beta-cell function in the pathogenesis of type 2 diabetes, an accurate and precise estimation of prehepatic insulin secretion rate (ISR) is essential. There are two common methods to assess ISR, the deconvolution method (by Eaton and Polonsky)-considered th......To detect and understand the changes in beta-cell function in the pathogenesis of type 2 diabetes, an accurate and precise estimation of prehepatic insulin secretion rate (ISR) is essential. There are two common methods to assess ISR, the deconvolution method (by Eaton and Polonsky...... of these mathematical techniques for quantification of insulin secretion have been tested in dogs, but not in humans. In the present studies, we examined the validity of both methods to recover the known infusion rates of insulin and C-peptide mimicking ISR during an oral glucose tolerance test. ISR from both......, and a close agreement was found for the results of an oral glucose tolerance test. We also studied whether C-peptide kinetics are influenced by somatostatin infusion. The decay curves after bolus injection of exogenous biosynthetic human C-peptide, the kinetic parameters, and the metabolic clearance rate were...

  8. Related Factors of Insulin Resistance in Korean Children: Adiposity and Maternal Insulin Resistance

    Directory of Open Access Journals (Sweden)

    Kang-Sook Lee

    2011-12-01

    Full Text Available Increased adiposity and unhealthy lifestyle augment the risk for type 2 diabetes in children with familial predisposition. Insulin resistance (IR is an excellent clinical marker for identifying children at high risk for type 2 diabetes. This study was conducted to investigate parental, physiological, behavioral and socio-economic factors related to IR in Korean children. This study is a cross-sectional study using data from 111 children aged 7 years and their parents. Homeostasis model assessment of insulin resistance (HOMA-IR was calculated using fasting glucose and insulin level as a marker of IR. All children’s adiposity indices (r = 0.309–0.318, all P-value = 0.001 and maternal levels of fasting insulin (r = 0.285, P-value = 0.003 and HOMA-IR (r = 0.290, P-value = 0.002 were positively correlated with children’s HOMA-IR level. There was no statistical difference of children’s HOMA-IR level according to children’s lifestyle habits and socioeconomic status of families. An increase of 1 percentage point in body fat was related to 2.7% increase in children’s HOMA-IR (P-value < 0.001 and an increase of 1% of maternal level of HOMA-IR was related to 0.2% increase in children’s HOMA-IR (P-value = 0.002. This study shows that children’s adiposity and maternal IR are positively associated with children’s IR.

  9. [Insulin resistance in the pathogenesis of polycystic ovarian disease (PCOD)].

    Science.gov (United States)

    Jakowicki, J

    1994-10-01

    In polycystic ovarian disease there is a strong association between hyperinsulinemia and hyperandrogenism but not with obesity alone. The magnitude of peripheral insulin resistance is similar to that seen in non-insulin-dependent diabetes mellitus. Mild hyperinsulinemia in PCOD patients is not impair the carbohydrate metabolism. The elimination of the cause of hyperandrogenism by bilateral oophorectomy, long-acting Gn-RH agonist or antiandrogen cyproterone acetate did not improve the associated insulin resistance. In opposition to insulin resistance in the tissues responsible for metabolism of carbohydrate, the ovary remains sensitive to the effects of pancreatic hormone. Presumably this mechanism involved the interaction with IGF-I receptors to stimulate thecal and stromal androgen production. Insulin may sensitize the stroma to the stimulatory effect of LH. In the mechanism of follicular arrest take part increased level of binding proteins for IGF-I, mainly IGFBP 2, -4 and 5 inhibit FSH and IGF-I action.

  10. The Association Between IGF-I and Insulin Resistance

    DEFF Research Database (Denmark)

    Friedrich, Nele; Thuesen, Betina; Jørgensen, Torben

    2012-01-01

    OBJECTIVEIGF-I has an almost 50% amino acid sequence homology with insulin and elicits nearly the same hypoglycemic response. Studies showed that low and high IGF-I levels are related to impaired glucose tolerance and to a higher risk of type 2 diabetes. The aim of the current study was to evaluate...... the association between IGF-I level and insulin resistance in a Danish general population.RESEARCH DESIGN AND METHODSIncluded were 3,354 adults, aged 19-72 years, from the cross-sectional Health2006 study. The homeostasis model assessment of insulin resistance (HOMA-IR) was used as the index to estimate insulin...... with intermediate (Q3) IGF-I levels. These associations remained statistically significant after the exclusion of subjects with type 2 diabetes and by using the updated computer HOMA2-IR model.CONCLUSIONSLow- and high-normal IGF-I levels are both related to insulin resistance. The biological mechanism...

  11. Obestatin regulates adipocyte function and protects against diet-induced insulin resistance and inflammation.

    Science.gov (United States)

    Granata, Riccarda; Gallo, Davide; Luque, Raul M; Baragli, Alessandra; Scarlatti, Francesca; Grande, Cristina; Gesmundo, Iacopo; Córdoba-Chacón, Jose; Bergandi, Loredana; Settanni, Fabio; Togliatto, Gabriele; Volante, Marco; Garetto, Stefano; Annunziata, Marta; Chanclón, Belén; Gargantini, Eleonora; Rocchietto, Stefano; Matera, Lina; Datta, Giacomo; Morino, Mario; Brizzi, Maria Felice; Ong, Huy; Camussi, Giovanni; Castaño, Justo P; Papotti, Mauro; Ghigo, Ezio

    2012-08-01

    The metabolic actions of the ghrelin gene-derived peptide obestatin are still unclear. We investigated obestatin effects in vitro, on adipocyte function, and in vivo, on insulin resistance and inflammation in mice fed a high-fat diet (HFD). Obestatin effects on apoptosis, differentiation, lipolysis, and glucose uptake were determined in vitro in mouse 3T3-L1 and in human subcutaneous (hSC) and omental (hOM) adipocytes. In vivo, the influence of obestatin on glucose metabolism was assessed in mice fed an HFD for 8 wk. 3T3-L1, hSC, and hOM preadipocytes and adipocytes secreted obestatin and showed specific binding for the hormone. Obestatin prevented apoptosis in 3T3-L1 preadipocytes by increasing phosphoinositide 3-kinase (PI3K)/Akt and extracellular signal-regulated kinase (ERK)1/2 signaling. In both mice and human adipocytes, obestatin inhibited isoproterenol-induced lipolysis, promoted AMP-activated protein kinase phosphorylation, induced adiponectin, and reduced leptin secretion. Obestatin also enhanced glucose uptake in either the absence or presence of insulin, promoted GLUT4 translocation, and increased Akt phosphorylation and sirtuin 1 (SIRT1) protein expression. Inhibition of SIRT1 by small interfering RNA reduced obestatin-induced glucose uptake. In HFD-fed mice, obestatin reduced insulin resistance, increased insulin secretion from pancreatic islets, and reduced adipocyte apoptosis and inflammation in metabolic tissues. These results provide evidence of a novel role for obestatin in adipocyte function and glucose metabolism and suggest potential therapeutic perspectives in insulin resistance and metabolic dysfunctions.

  12. A case of insulin and ACTH co-secretion by a neuroendocrine tumour.

    Science.gov (United States)

    Solomou, S; Khan, R; Propper, D; Berney, D; Druce, M

    2014-01-01

    A 33-year-old male was diagnosed with a metastatic neuroendocrine carcinoma of uncertain primary. He defaulted from follow-up without therapy and some months later developed episodic severe hypoglycaemia, which was found to be associated with inappropriately elevated insulin and C-peptide levels. It was considered likely that the neuroendocrine tumour was the source of the insulin secretion. Diazoxide and somatostatin analogue were used to control hypoglycaemia. Much later in the course of the disease, he developed metabolic derangement, increased skin pigmentation and psychological disturbance, without frankly Cushingoid physical findings. Investigations revealed highly elevated cortisol levels (the levels having previously been normal) with markedly raised ACTH levels, consistent with the co-secretion of ACTH and insulin by the tumour. Treatment with metyrapone improved his psychological state and electrolyte imbalance. Unfortunately, despite several cycles of first-, second- and third-line chemotherapy from the start of the first hormonal presentation onwards, imaging revealed widespread progressive metastatic disease and the patient eventually passed away. This case highlights the importance of keeping in mind the biochemical heterogeneity of endocrine tumours during their treatment. The clinical presentation of insulin-secreting tumours includes symptoms of neuroglycopaenia and sympathetic overstimulation.Tumour-associated hypoglycaemia can be due to pancreatic insulinomas, and although ectopic hormone production occurs in a number of tumours, ectopic secretion of insulin is rare.A possible switch in the type of hormone produced can occur during the growth and progression of neuroendocrine tumours and, when treating neuroendocrine tumours, it is important to keep in mind their biochemical heterogeneity.

  13. Impaired Sympathoadrenal Axis Function Contributes to Enhanced Insulin Secretion in Prediabetic Obese Rats

    Directory of Open Access Journals (Sweden)

    Ana Eliza Andreazzi

    2011-01-01

    Full Text Available The involvement of sympathoadrenal axis activity in obesity onset was investigated using the experimental model of treating neonatal rats with monosodium L-glutamate. To access general sympathetic nervous system activity, we recorded the firing rates of sympathetic superior cervical ganglion nerves in animals. Catecholamine content and secretion from isolated adrenal medulla were measured. Intravenous glucose tolerance test was performed, and isolated pancreatic islets were stimulated with glucose and adrenergic agonists. The nerve firing rate of obese rats was decreased compared to the rate for lean rats. Basal catecholamine secretion decreased whereas catecholamine secretion induced by carbachol, elevated extracellular potassium, and caffeine in the isolated adrenal medulla were all increased in obese rats compared to control. Both glucose intolerance and hyperinsulinaemia were observed in obese rats. Adrenaline strongly inhibited glucose-induced insulin secretion in obese animals. These findings suggest that low sympathoadrenal activity contributes to impaired glycaemic control in prediabetic obese rats.

  14. Glucagon-like peptide 1 (GLP-1) suppresses ghrelin levels in humans via increased insulin secretion

    DEFF Research Database (Denmark)

    Hagemann, Dirk; Holst, Jens Juul; Gethmann, Arnica

    2007-01-01

    INTRODUCTION: Ghrelin is an orexigenic peptide predominantly secreted by the stomach. Ghrelin plasma levels rise before meal ingestion and sharply decline afterwards, but the mechanisms controlling ghrelin secretion are largely unknown. Since meal ingestion also elicits the secretion...... of the incretin hormone glucagon-like peptide 1 (GLP-1), we examined whether exogenous GLP-1 administration reduces ghrelin secretion in humans. PATIENTS AND METHODS: 14 healthy male volunteers were given intravenous infusions of GLP-1(1.2 pmol x kg(-1) min(-1)) or placebo over 390 min. After 30 min, a solid test...... meal was served. Venous blood was drawn frequently for the determination of glucose, insulin, C-peptide, GLP-1 and ghrelin. RESULTS: During the infusion of exogenous GLP-1 and placebo, GLP-1 plasma concentrations reached steady-state levels of 139+/-15 pmol/l and 12+/-2 pmol/l, respectively (p

  15. Environmental factors and dam characteristics associated with insulin sensitivity and insulin secretion in newborn Holstein calves

    International Nuclear Information System (INIS)

    Kamal, M.M.; Van Eetvelde, M.; Bogaert, H.; Hostens, M.; Vandaele, L.; Shamsuddin, M.; Opsomer, G.

    2015-01-01

    The objective of the present retrospective cohort study was to evaluate potential associations between environmental factors and dam characteristics, including level of milk production during gestation, and insulin traits in newborn Holstein calves

  16. Complete loss of insulin secretion capacity in type 1A diabetes patients during long-term follow up.

    Science.gov (United States)

    Uno, Sae; Imagawa, Akihisa; Kozawa, Junji; Fukui, Kenji; Iwahashi, Hiromi; Shimomura, Iichiro

    2017-10-16

    Patients with type 1 diabetes are classified into three subtypes in Japan: acute onset, fulminant and slowly progressive. Acute-onset type 1 diabetes would be equivalent to type 1A diabetes, the typical type 1 diabetes in Western countries. The insulin secretion capacity in Japanese patients with long-standing type 1A diabetes is unclear. The aim of the present study was to clarify the course of endogenous insulin secretion during long-term follow up and the factors associated with residual insulin secretion in patients with acute-onset type 1 diabetes (autoimmune). We retrospectively investigated endogenous insulin secretion capacity in 71 patients who fulfilled the diagnostic criteria for acute-onset type 1 diabetes (autoimmune) in Japan. To assess the residual insulin secretion capacity, we evaluated randomly measured C-peptide levels and the results of glucagon stimulation test in 71 patients. In the first year of disease, the child- and adolescent-onset patients had significantly more in residual insulin secretion than the adult-onset patients (34 patients in total). C-peptide levels declined more rapidly in patients whose age of onset was ≤18 years than in patients whose age of onset was ≥19 years. Endogenous insulin secretion capacity stimulated by glucagon was completely lost in almost all patients at >15 years after onset (61 patients in total). Most patients with acute-onset type 1 diabetes (autoimmune) completely lose their endogenous insulin secretion capacity during the disease duration in Japan. Age of onset might affect the course of insulin secretion. © 2017 The Authors. Journal of Diabetes Investigation published by Asian Association for the Study of Diabetes (AASD) and John Wiley & Sons Australia, Ltd.

  17. [Severe type A insulin resistance syndrome due to a mutation in the insulin receptor gene].

    Science.gov (United States)

    Ros, P; Colino-Alcol, E; Grasso, V; Barbetti, F; Argente, J

    2015-01-01

    Insulin resistance syndromes without lipodystrophy are an infrequent and heterogeneous group of disorders with variable clinical phenotypes, associated with hyperglycemia and hyperinsulinemia. The three conditions related to mutations in the insulin receptor gene are leprechaunism or Donohue syndrome, Rabson-Mendenhall syndrome, and Type A syndrome. A case is presented on a patient diagnosed with type A insulin resistance, defined by the triad of extreme insulin resistance, acanthosis nigricans, and hyperandrogenism, carrying a heterozygous mutation in exon 19 of the insulin receptor gene coding for its tyrosine kinase domain that is crucial for the catalytic activity of the receptor. The molecular basis of the syndrome is reviewed, focusing on the structure-function relationships of the insulin receptor, knowing that the criteria for survival are linked to residual insulin receptor function. It is also pointed out that, although type A insulin resistance appears to represent a somewhat less severe condition, these patients have a high morbidity and their treatment is still unsatisfactory. Copyright © 2014 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

  18. Insulin resistance in Nigerians with essential hypertension | Akande ...

    African Journals Online (AJOL)

    Homeostasis model assessment (HOMA) was used to determine insulin resistance (IR). Results: The hypertensive subjects had significantly higher fasting insulin and HOMA-IR compared with normotensives (p =0.02 and 0.04) respectively. There were significant correlations between HOMA-IR, BMI, waist and hip ...

  19. Radiation resistivity of frozen insulin solutions and suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Soboleva, N N; Ivanova, A I; Talrose, V L; Trofimov, V I; Fedotov, V P [AN SSSR, Moscow. Inst. Fizicheskoj Khimii; Research Institute for Biological Testing of Chemicals, Moscow (USSR); Institute of Experimental Endocrinology and Hormon Chemistry, Moscow (USSR))

    1981-10-01

    The effect of great increase in radiation resistance of insulin solutions and suspensions after irradiation at low temperatures in the frozen state was observed by absorption spectrophotometry, paper chromatography and biological analysis. The data obtained suggest irradiation of frozen insulin solutions and suspensions as a method for its sterilization.

  20. Cognitively impaired elderly exhibit insulin resistance and no memory improvement with infused insulin.

    Science.gov (United States)

    Morris, Jill K; Vidoni, Eric D; Mahnken, Jonathan D; Montgomery, Robert N; Johnson, David K; Thyfault, John P; Burns, Jeffrey M

    2016-03-01

    Insulin resistance is a risk factor for Alzheimer's disease (AD), although its role in AD etiology is unclear. We assessed insulin resistance using fasting and insulin-stimulated measures in 51 elderly subjects with no dementia (ND; n = 37) and with cognitive impairment (CI; n = 14). CI subjects exhibited either mild CI or AD. Fasting insulin resistance was measured using the homeostatic model assessment of insulin resistance (HOMA-IR). Insulin-stimulated glucose disposal was assessed using the hyperinsulinemic-euglycemic clamp to calculate glucose disposal rate into lean mass, the primary site of insulin-stimulated glucose disposal. Because insulin crosses the blood-brain barrier, we also assessed whether insulin infusion would improve verbal episodic memory compared to baseline. Different but equivalent versions of cognitive tests were administered in counterbalanced order in the basal and insulin-stimulated state. Groups did not differ in age or body mass index. Cognitively impaired subjects exhibited greater insulin resistance as measured at fasting (HOMA-IR; ND: 1.09 [1.1] vs. CI: 2.01 [2.3], p = 0.028) and during the hyperinsulinemic clamp (glucose disposal rate into lean mass; ND: 9.9 (4.5) vs. AD 7.2 (3.2), p = 0.040). Cognitively impaired subjects also exhibited higher fasting insulin compared to ND subjects, (CI: 8.7 [7.8] vs. ND: 4.2 [3.8] μU/mL; p = 0.023) and higher fasting amylin (CI: 24.1 [39.1] vs. 8.37 [14.2]; p = 0.050) with no difference in fasting glucose. Insulin infusion elicited a detrimental effect on one test of verbal episodic memory (Free and Cued Selective Reminding Test) in both groups (p insulin resistance was observed in cognitively impaired subjects compared to ND controls, insulin infusion did not improve memory. Furthermore, a significant correlation between HOMA-IR and glucose disposal rate was present only in ND (p = 0.0002) but not in cognitively impaired (p = 0.884) subjects, indicating potentially important

  1. Nuclear SREBP-1a causes loss of pancreatic β-cells and impaired insulin secretion

    International Nuclear Information System (INIS)

    Iwasaki, Yuko; Iwasaki, Hitoshi; Yatoh, Shigeru; Ishikawa, Mayumi; Kato, Toyonori; Matsuzaka, Takashi; Nakagawa, Yoshimi; Yahagi, Naoya; Kobayashi, Kazuto; Takahashi, Akimitsu; Suzuki, Hiroaki; Yamada, Nobuhiro; Shimano, Hitoshi

    2009-01-01

    Transgenic mice expressing nuclear sterol regulatory element-binding protein-1a under the control of the insulin promoter were generated to determine the role of SREBP-1a in pancreatic β-cells. Only low expressors could be established, which exhibited mild hyperglycemia, impaired glucose tolerance, and reduced plasma insulin levels compared to C57BL/6 controls. The islets isolated from the transgenic mice were fewer and smaller, and had decreased insulin content and unaltered glucagon staining. Both glucose- and potassium-stimulated insulin secretions were decreased. The transgenic islets consistently expressed genes for fatty acids and cholesterol synthesis, resulting in accumulation of triglycerides but not cholesterol. PDX-1, ΒΕΤΑ2, MafA, and IRS-2 were suppressed, partially explaining the loss and dysfunction of β-cell mass. The transgenic mice on a high fat/high sucrose diet still exhibited impaired insulin secretion and continuous β-cell growth defect. Therefore, nuclear SREBP-1a, even at a low level, strongly disrupts β-cell mass and function.

  2. Integrative network analysis highlights biological processes underlying GLP-1 stimulated insulin secretion: A DIRECT study.

    Directory of Open Access Journals (Sweden)

    Valborg Gudmundsdottir

    Full Text Available Glucagon-like peptide 1 (GLP-1 stimulated insulin secretion has a considerable heritable component as estimated from twin studies, yet few genetic variants influencing this phenotype have been identified. We performed the first genome-wide association study (GWAS of GLP-1 stimulated insulin secretion in non-diabetic individuals from the Netherlands Twin register (n = 126. This GWAS was enhanced using a tissue-specific protein-protein interaction network approach. We identified a beta-cell protein-protein interaction module that was significantly enriched for low gene scores based on the GWAS P-values and found support at the network level in an independent cohort from Tübingen, Germany (n = 100. Additionally, a polygenic risk score based on SNPs prioritized from the network was associated (P < 0.05 with glucose-stimulated insulin secretion phenotypes in up to 5,318 individuals in MAGIC cohorts. The network contains both known and novel genes in the context of insulin secretion and is enriched for members of the focal adhesion, extracellular-matrix receptor interaction, actin cytoskeleton regulation, Rap1 and PI3K-Akt signaling pathways. Adipose tissue is, like the beta-cell, one of the target tissues of GLP-1 and we thus hypothesized that similar networks might be functional in both tissues. In order to verify peripheral effects of GLP-1 stimulation, we compared the transcriptome profiling of ob/ob mice treated with liraglutide, a clinically used GLP-1 receptor agonist, versus baseline controls. Some of the upstream regulators of differentially expressed genes in the white adipose tissue of ob/ob mice were also detected in the human beta-cell network of genes associated with GLP-1 stimulated insulin secretion. The findings provide biological insight into the mechanisms through which the effects of GLP-1 may be modulated and highlight a potential role of the beta-cell expressed genes RYR2, GDI2, KIAA0232, COL4A1 and COL4A2 in GLP-1 stimulated

  3. High dietary protein intake, reducing or eliciting insulin resistance?

    NARCIS (Netherlands)

    Rietman, A.; Schwarz, J.; Tome, D.; Kok, F.J.; Mensink, M.R.

    2014-01-01

    Dietary proteins have an insulinotropic effect and thus promote insulin secretion, which indeed leads to enhanced glucose clearance from the blood. In the long term, however, a high dietary protein intake is associated with an increased risk of type 2 diabetes. Moreover, branched-chain amino acids

  4. The effect of a very low calorie diet on insulin sensitivity, beta cell function, insulin clearance, incretin hormone secretion, androgen levels and body composition in obese young women

    DEFF Research Database (Denmark)

    Svendsen, Pernille F; Jensen, Frank K; Holst, Jens Juul

    2012-01-01

    Evaluation of the effect of an 8-week very low calorie diet (VLCD, 500-600 kcal daily) on weight, body fat distribution, glucose, insulin and lipid metabolism, androgen levels and incretin secretion in obese women.......Evaluation of the effect of an 8-week very low calorie diet (VLCD, 500-600 kcal daily) on weight, body fat distribution, glucose, insulin and lipid metabolism, androgen levels and incretin secretion in obese women....

  5. Intra- and Inter-islet Synchronization of Metabolically Driven Insulin Secretion

    DEFF Research Database (Denmark)

    Pedersen, Morten Gram; Bertram, Richard; Sherman, Arthur

    2005-01-01

    mechanisms for intra-islet and inter-islet synchronization. We show that electrical coupling is sufficient to synchronize both electrical bursting activity and metabolic oscillations. We also demonstrate that islets can synchronize by mutually entraining each other by their effects on a simple model "liver......,'' which responds to the level of insulin secretion by adjusting the blood glucose concentration in an appropriate way. Since all islets are exposed to the blood, the distributed islet-liver system can synchronize the individual islet insulin oscillations. Thus, we demonstrate how intra-islet and inter...

  6. Fasting insulin, insulin resistance and risk of hypertension in the general population: A meta-analysis.

    Science.gov (United States)

    Wang, Feng; Han, Lili; Hu, Dayi

    2017-01-01

    Studies on the association of fasting insulin concentrations or insulin resistance with subsequent risk of hypertension have yielded conflicting results. To quantitatively assess the association of fasting insulin concentrations or homeostasis model assessment insulin resistance (HOMA-IR) with incident hypertension in a general population by performing a meta-analysis. We searched the PubMed and Embase databases until August 31, 2016 for prospective observational studies investigating the elevated fasting insulin concentrations or HOMA-IR with subsequent risk of hypertension in the general population. Pooled risk ratio (RR) and 95% confidence interval (CI) of hypertension was calculated for the highest versus the lowest category of fasting insulin or HOMA-IR. Eleven studies involving 10,230 hypertension cases were identified from 55,059 participants. Meta-analysis showed that the pooled adjusted RR of hypertension was 1.54 (95% CI 1.34-1.76) for fasting insulin concentrations and 1.43 (95% CI 1.27-1.62) for HOMA-IR comparing the highest to the lowest category. Subgroup analysis results showed that the association of fasting insulin concentrations with subsequent risk of hypertension seemed more pronounced in women (RR 2.07; 95% CI 1.19-3.60) than in men (RR 1.48; 95% CI 1.17-1.88). This meta-analysis suggests that elevated fasting insulin concentrations or insulin resistance as estimated by homeostasis model assessment is independently associated with an exacerbated risk of hypertension in the general population. Early intervention of hyperinsulinemia or insulin resistance may help clinicians to identify the high risk of hypertensive population. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Xylitol prevents NEFA-induced insulin resistance in rats

    Science.gov (United States)

    Kishore, P.; Kehlenbrink, S.; Hu, M.; Zhang, K.; Gutierrez-Juarez, R.; Koppaka, S.; El-Maghrabi, M. R.

    2013-01-01

    Aims/hypothesis Increased NEFA levels, characteristic of type 2 diabetes mellitus, contribute to skeletal muscle insulin resistance. While NEFA-induced insulin resistance was formerly attributed to decreased glycolysis, it is likely that glucose transport is the rate-limiting defect. Recently, the plant-derived sugar alcohol xylitol has been shown to have favourable metabolic effects in various animal models. Furthermore, its derivative xylulose 5-phosphate may prevent NEFA-induced suppression of glycolysis. We therefore examined whether and how xylitol might prevent NEFA-induced insulin resistance. Methods We examined the ability of xylitol to prevent NEFA-induced insulin resistance. Sustained ~1.5-fold elevations in NEFA levels were induced with Intralipid/heparin infusions during 5 h euglycaemic–hyperinsulinaemic clamp studies in 24 conscious non-diabetic Sprague-Dawley rats, with or without infusion of xylitol. Results Intralipid infusion reduced peripheral glucose uptake by ~25%, predominantly through suppression of glycogen synthesis. Co-infusion of xylitol prevented the NEFA-induced decreases in both glucose uptake and glycogen synthesis. Although glycolysis was increased by xylitol infusion alone, there was minimal NEFA-induced suppression of glycolysis, which was not affected by co-infusion of xylitol. Conclusions/interpretation We conclude that xylitol prevented NEFA-induced insulin resistance, with favourable effects on glycogen synthesis accompanying the improved insulin-mediated glucose uptake. This suggests that this pentose sweetener has beneficial insulin-sensitising effects. PMID:22460760

  8. The etiology of oxidative stress in insulin resistance

    Directory of Open Access Journals (Sweden)

    Samantha Hurrle

    2017-10-01

    Full Text Available Insulin resistance is a prevalent syndrome in developed as well as developing countries. It is the predisposing factor for type 2 diabetes mellitus, the most common end stage development of metabolic syndrome in the United States. Previously, studies investigating type 2 diabetes have focused on beta cell dysfunction in the pancreas and insulin resistance, and developing ways to correct these dysfunctions. However, in recent years, there has been a profound interest in the role that oxidative stress in the peripheral tissues plays to induce insulin resistance. The objective of this review is to focus on the mechanism of oxidative species generation and its direct correlation to insulin resistance, to discuss the role of obesity in the pathophysiology of this phenomenon, and to explore the potential of antioxidants as treatments for metabolic dysfunction.

  9. Prevalence of the insulin resistance syndrome in obesity

    OpenAIRE

    Viner, R; Segal, T; Lichtarowicz-Kryn..., E; Hindmarsh, P

    2005-01-01

    Aims: To assess prevalence of the insulin resistance syndrome (IRS: obesity, abnormal glucose homoeostasis, dyslipidaemia, and hypertension) in obese UK children and adolescents of different ethnicities and to assess whether fasting data is sufficient to identify IRS in childhood obesity.

  10. Diagnostic criteria for sarcopenia relate differently to insulin resistance

    NARCIS (Netherlands)

    Bijlsma, A.Y.; Meskers, C.G.M.; van Heemst, D.; Westendorp, R.G.J.; Craen, A.J.M.; Maier, A.B.

    2013-01-01

    Skeletal muscle is important in insulinstimulated glucose uptake. Sarcopenia is, therefore, a possible risk factor for insulin resistance. Currently, different diagnostic criteria for sarcopenia include low muscle mass, muscle strength, and walking speed. We assessed these muscle characteristics in

  11. Exploring pathway interactions in insulin resistant mouse liver

    NARCIS (Netherlands)

    Kelder, T.; Eijssen, L.; Kleemann, R.; Erk, M. van; Kooistra, T.; Evelo, C.

    2011-01-01

    Background: Complex phenotypes such as insulin resistance involve different biological pathways that may interact and influence each other. Interpretation of related experimental data would be facilitated by identifying relevant pathway interactions in the context of the dataset.Results: We

  12. Suppression in growth hormone during overeating ameliorates the increase in insulin resistance and cardiovascular disease risk.

    Science.gov (United States)

    Cornford, Andrea S; Barkan, Ariel L; Hinko, Alexander; Horowitz, Jeffrey F

    2012-11-15

    Previously, we reported that overeating for only a few days markedly suppressed the secretion of growth hormone (GH). The purpose of the present study was to determine the role of this reduction in GH concentration on key metabolic adaptations that occur during 2 wk of overeating. Nine nonobese, healthy adults were admitted to the hospital for 2 wk, during which time they ate ∼4,000 kcal/day (70 kcal·kg fat-free mass(-1)·day(-1); 50% carbohydrate, 35% fat, and 15% protein), and their plasma GH concentration was allowed to decline naturally (control). An additional eight subjects underwent the same overeating intervention and received exogenous GH treatment (GHT) administered in four daily injections to mimic physiological GH secretion throughout the 2-wk overeating period. We measured plasma insulin and glucose concentrations in the fasting and postprandial state as well as fasting lipolytic rate, proteolytic rate, and fractional synthetic rate (FSR) using stable-isotope tracer methods. GHT prevented the fall in plasma GH concentration, maintaining plasma GH concentration at baseline levels (1.2 ± 0.2 ng/ml), which increased fasting and postprandial assessments of insulin resistance (P overeating also blunted the increase in systemic proteolysis (P overeating. In conclusion, our main findings suggest that the suppression in GH secretion that naturally occurs during the early stages of overeating may help attenuate the insulin resistance and hyperlipidemia that typically accompany overeating.

  13. Childhood craniopharyngioma: greater hypothalamic involvement before surgery is associated with higher homeostasis model insulin resistance index

    Science.gov (United States)

    Trivin, Christine; Busiah, Kanetee; Mahlaoui, Nizar; Recasens, Christophe; Souberbielle, Jean-Claude; Zerah, Michel; Sainte-Rose, Christian; Brauner, Raja

    2009-01-01

    Background Obesity seems to be linked to the hypothalamic involvement in craniopharyngioma. We evaluated the pre-surgery relationship between the degree of this involvement on magnetic resonance imaging and insulin resistance, as evaluated by the homeostasis model insulin resistance index (HOMA). As insulin-like growth factor 1, leptin, soluble leptin receptor (sOB-R) and ghrelin may also be involved, we compared their plasma concentrations and their link to weight change. Methods 27 children with craniopharyngioma were classified as either grade 0 (n = 7, no hypothalamic involvement), grade 1 (n = 8, compression without involvement), or grade 2 (n = 12, severe involvement). Results Despite having similar body mass indexes (BMI), the grade 2 patients had higher glucose, insulin and HOMA before surgery than the grade 0 (P = 0.02, craniopharyngioma before surgery seems to determine the degree of insulin resistance, regardless of the BMI. The pre-surgery HOMA values were correlated with the post-surgery weight gain. This suggests that obesity should be prevented by reducing inn secretion in those cases with hypothalamic involvement. PMID:19341477

  14. Effects of Bariatric Surgery on Adipokine-Induced Inflammation and Insulin Resistance

    Directory of Open Access Journals (Sweden)

    Zeynep eGoktas

    2013-06-01

    Full Text Available Over a third of the US population is obese and at high risk for developing type 2 diabetes, insulin resistance and other metabolic disorders. Obesity is considered a chronic low grade inflammatory condition that is primarily attributed to expansion and inflammation of adipose tissues. Indeed, adipocytes produce and secrete numerous proinflammatory and anti-inflammatory cytokines known as adipokines. When the balance of these adipokines is shifted towards higher production of proinflammatory factors, local inflammation within adipose tissues and subsequently systemic inflammation occur. These adipokines including leptin, visfatin, resistin, apelin, vaspin, and retinol binding protein-4 can regulate inflammatory responses and contribute to the pathogenesis of diabetes. These effects are mediated by key inflammatory signaling molecules including activated serine kinases such as c-Jun N-terminal kinase (JNK and serine kinases inhibitor κB kinase (IKK and insulin signaling molecules including insulin receptor substrates, protein kinase B (PKB, also known as Akt, and nuclear factor kappa B (NF-kB. Bariatric surgery can decrease body weight and improve insulin resistance in morbidly obese subjects. However, despite reports suggesting reduced inflammation and weight-independent effects of bariatric surgery on glucose metabolism, mechanisms behind such improvements are not yet well understood. This review article focuses on some of these novel adipokines and discusses their changes after bariatric surgery and their relationship to insulin resistance, fat mass, inflammation, and glucose homeostasis.

  15. Childhood craniopharyngioma: greater hypothalamic involvement before surgery is associated with higher homeostasis model insulin resistance index

    Directory of Open Access Journals (Sweden)

    Sainte-Rose Christian

    2009-04-01

    Full Text Available Abstract Background Obesity seems to be linked to the hypothalamic involvement in craniopharyngioma. We evaluated the pre-surgery relationship between the degree of this involvement on magnetic resonance imaging and insulin resistance, as evaluated by the homeostasis model insulin resistance index (HOMA. As insulin-like growth factor 1, leptin, soluble leptin receptor (sOB-R and ghrelin may also be involved, we compared their plasma concentrations and their link to weight change. Methods 27 children with craniopharyngioma were classified as either grade 0 (n = 7, no hypothalamic involvement, grade 1 (n = 8, compression without involvement, or grade 2 (n = 12, severe involvement. Results Despite having similar body mass indexes (BMI, the grade 2 patients had higher glucose, insulin and HOMA before surgery than the grade 0 (P = 0.02, The data for the whole population before and 6–18 months after surgery showed increases in BMI (P Conclusion The hypothalamic involvement by the craniopharyngioma before surgery seems to determine the degree of insulin resistance, regardless of the BMI. The pre-surgery HOMA values were correlated with the post-surgery weight gain. This suggests that obesity should be prevented by reducing inn secretion in those cases with hypothalamic involvement.

  16. [Reliability of HOMA-IR for evaluation of insulin resistance during perioperative period].

    Science.gov (United States)

    Fujino, Hiroko; Itoda, Shoko; Sako, Saori; Matsuo, Kazuki; Sakamoto, Eiji; Yokoyama, Takeshi

    2013-02-01

    Hyperglycemia due to increase in insulin resistance (IR) is often observed after surgery in spite of normal insulin secretion. To evaluate the degree of IR, the golden standard method is the normoglycemic hyperinsulinemic clamp technique (glucose clamp: GC). The GC using the artificial pancreas, STG-22 (Nikkiso, Tokyo, Japan), was established as a more reliable method, since it was evaluated during steady-state period under constant insulin infusion. Homeostasis model assessment insulin resistance (HOMA-IR), however, is frequently employed in daily practice because of its convenience. We, therefore, investigated the reliability of HOMA-IR in comparison with the glucose clamp using the STG-22. Eight healthy patients undergoing maxillofacial surgery were employed in this study after obtaining written informed consent. Their insulin resistance was evaluated by HOMA-IR and the GC using the STG-22 before and after surgery. HOMA-IR increased from 0.81 +/- 0.48 to 1.17 +/- 0.50, although there were no significant differences between before and after surgery. On the other hand, M-value by GC significantly decreased after surgery from 8.82 +/- 2.49 mg x kg(-1) x min(-1) to 3.84 +/- 0.79 mg x kg(-1) x min(-1) (P = 0.0003). In addition, no significant correlation was found between the values of HOMA-IR and the M-value by GC. HOMA-IR may not be reliable to evaluate IR for perioperative period.

  17. Insulin Secretion and Risk for Future Diabetes in Subjects with a Nonpositive Insulinogenic Index

    Directory of Open Access Journals (Sweden)

    Daisuke Aono

    2018-01-01

    Full Text Available Aim. To characterize subjects with a nonpositive insulinogenic index and longitudinally observe changes in their glucose tolerance. Subjects and Methods. A historical cohort study was conducted using data from the medical checkups of public school workers. Indices of insulin secretion and insulin sensitivity derived from oral glucose tolerance test (OGTT and the incidences of diabetes and impaired glucose tolerance (IGT were compared among subgroups of subjects with different insulinogenic index (change in insulin/change in glucose over the first 30 min on the OGTT. Results. Of the 1464 nondiabetic subjects at baseline, 72 (4.9% subjects had a nonpositive insulinogenic index: 42 of those subjects had a nonpositive glucose response (ΔGlu0–30 ≤ 0 and 30 had a nonpositive insulin response (ΔIns0–30 ≤ 0. Compared with subjects who had normal glucose tolerance (NGT with insulinogenic index ≥ 0.4, subjects with a nonpositive glucose response had a higher first-phase Stumvoll and lower incidences of diabetes and IGT based on a log-rank test (p<0.05, whereas subjects with a nonpositive insulin response had lower indices of insulin secretion and a higher incidence of diabetes (p<0.05. Conclusions. These results demonstrate that in the first 30 min on the OGTT, subjects with a nonpositive insulinogenic index due to a nonpositive glucose response (ΔGlu0–30 ≤ 0 had a lower risk for future diabetes and that subjects with nonpositive insulin response (ΔIns0–30 ≤ 0 had a higher risk for future one.

  18. Insulin resistance and exercise tolerance in heart failure patients

    DEFF Research Database (Denmark)

    Snoer, Martin; Monk-Hansen, Tea; Olsen, Rasmus Huan

    2012-01-01

    Insulin resistance has been linked to exercise intolerance in heart failure patients. The aim of this study was to assess the potential role of coronary flow reserve (CFR), endothelial function and arterial stiffness in explaining this linkage.......Insulin resistance has been linked to exercise intolerance in heart failure patients. The aim of this study was to assess the potential role of coronary flow reserve (CFR), endothelial function and arterial stiffness in explaining this linkage....

  19. RELATIONSHIP BETWEEN URIC ACID METABOLISM AND INSULIN RESISTANCE

    OpenAIRE

    辻本, 伸宏; 金内, 雅夫; 尾崎, 博基; 藤田, 泰三; 中嶋, 民夫; 土肥, 和紘

    1998-01-01

    To investigate the relationship between uric acid (UA) metabolism and insulin resistance, serum creatinine concentration (Scr), serum UA concentration (SuA) and the urinary excretion of creatinine and UA were determined in 25 non-diabetic patients. Creatinine clearance (Ccr) and UA clearance/creatinine clearance ratio (CuA/Ccr) were also calculated. Insulin resistance was evaluated by the euglycemic glucose clamp tech- nique and expressed as the mean value of the glucose infusion rate (M-valu...

  20. Insulin Resistance Induced by Hyperinsulinemia Coincides with a Persistent Alteration at the Insulin Receptor Tyrosine Kinase Domain

    Science.gov (United States)

    Catalano, Karyn J.; Maddux, Betty A.; Szary, Jaroslaw; Youngren, Jack F.; Goldfine, Ira D.; Schaufele, Fred

    2014-01-01

    Insulin resistance, the diminished response of target tissues to insulin, is associated with the metabolic syndrome and a predisposition towards diabetes in a growing proportion of the worldwide population. Under insulin resistant states, the cellular response of the insulin signaling pathway is diminished and the body typically responds by increasing serum insulin concentrations to maintain insulin signaling. Some evidence indicates that the increased insulin concentration may itself further dampen insulin response. If so, insulin resistance would worsen as the level of circulating insulin increases during compensation, which could contribute to the transition of insulin resistance to more severe disease. Here, we investigated the consequences of excess insulin exposure to insulin receptor (IR) activity. Cells chronically exposed to insulin show a diminished the level of IR tyrosine and serine autophosphorylation below that observed after short-term insulin exposure. The diminished IR response did not originate with IR internalization since IR amounts at the cell membrane were similar after short- and long-term insulin incubation. Förster resonance energy transfer between fluorophores attached to the IR tyrosine kinase (TK) domain showed that a change in the TK domain occurred upon prolonged, but not short-term, insulin exposure. Even though the altered ‘insulin refractory’ IR TK FRET and IR autophosphorylation levels returned to baseline (non-stimulated) levels after wash-out of the original insulin stimulus, subsequent short-term exposure to insulin caused immediate re-establishment of the insulin-refractory levels. This suggests that some cell-based ‘memory’ of chronic hyperinsulinemic exposure acts directly at the IR. An improved understanding of that memory may help define interventions to reset the IR to full insulin responsiveness and impede the progression of insulin resistance to more severe disease states. PMID:25259572

  1. Insulin resistance induced by hyperinsulinemia coincides with a persistent alteration at the insulin receptor tyrosine kinase domain.

    Directory of Open Access Journals (Sweden)

    Karyn J Catalano

    Full Text Available Insulin resistance, the diminished response of target tissues to insulin, is associated with the metabolic syndrome and a predisposition towards diabetes in a growing proportion of the worldwide population. Under insulin resistant states, the cellular response of the insulin signaling pathway is diminished and the body typically responds by increasing serum insulin concentrations to maintain insulin signaling. Some evidence indicates that the increased insulin concentration may itself further dampen insulin response. If so, insulin resistance would worsen as the level of circulating insulin increases during compensation, which could contribute to the transition of insulin resistance to more severe disease. Here, we investigated the consequences of excess insulin exposure to insulin receptor (IR activity. Cells chronically exposed to insulin show a diminished the level of IR tyrosine and serine autophosphorylation below that observed after short-term insulin exposure. The diminished IR response did not originate with IR internalization since IR amounts at the cell membrane were similar after short- and long-term insulin incubation. Förster resonance energy transfer between fluorophores attached to the IR tyrosine kinase (TK domain showed that a change in the TK domain occurred upon prolonged, but not short-term, insulin exposure. Even though the altered 'insulin refractory' IR TK FRET and IR autophosphorylation levels returned to baseline (non-stimulated levels after wash-out of the original insulin stimulus, subsequent short-term exposure to insulin caused immediate re-establishment of the insulin-refractory levels. This suggests that some cell-based 'memory' of chronic hyperinsulinemic exposure acts directly at the IR. An improved understanding of that memory may help define interventions to reset the IR to full insulin responsiveness and impede the progression of insulin resistance to more severe disease states.

  2. Acupuncture Alters Expression of Insulin Signaling Related Molecules and Improves Insulin Resistance in OLETF Rats

    Directory of Open Access Journals (Sweden)

    Xin-Yu Huang

    2016-01-01

    Full Text Available To determine effect of acupuncture on insulin resistance in Otsuka Long-Evans Tokushima Fatty (OLETF rats and to evaluate expression of insulin signaling components. Rats were divided into three groups: Sprague-Dawley (SD rats, OLETF rats, and acupuncture+OLETF rats. Acupuncture was subcutaneously applied to Neiguan (PC6, Zusanli (ST36, and Sanyinjiao (SP6; in contrast, acupuncture to Shenshu (BL23 was administered perpendicularly. For Neiguan (PC6 and Zusanli (ST36, needles were connected to an electroacupuncture (EA apparatus. Fasting blood glucose (FPG was measured by glucose oxidase method. Plasma fasting insulin (FINS and serum C peptide (C-P were determined by ELISA. Protein and mRNA expressions of insulin signaling molecules were determined by Western blot and real-time RT-PCR, respectively. OLETF rats exhibit increased levels of FPG, FINS, C-P, and homeostasis model assessment-estimated insulin resistance (HOMA-IR, which were effectively decreased by acupuncture treatment. mRNA expressions of several insulin signaling related molecules IRS1, IRS2, Akt2, aPKCζ, and GLUT4 were decreased in OLETF rats compared to SD controls. Expression of these molecules was restored back to normal levels upon acupuncture administration. PI3K-p85α was increased in OLETF rats; this increase was also reversed by acupuncture treatment. Acupuncture improves insulin resistance in OLETF rats, possibly via regulating expression of key insulin signaling related molecules.

  3. Integrative network analysis highlights biological processes underlying GLP-1 stimulated insulin secretion: A DIRECT study

    DEFF Research Database (Denmark)

    Gudmundsdottir, Valborg; Pedersen, Helle Krogh; Allebrandt, Karla Viviani

    2018-01-01

    Glucagon-like peptide 1 (GLP-1) stimulated insulin secretion has a considerable heritable component as estimated from twin studies, yet few genetic variants influencing this phenotype have been identified. We performed the first genome-wide association study (GWAS) of GLP-1 stimulated insulin...... secretion in non-diabetic individuals from the Netherlands Twin register (n = 126). This GWAS was enhanced using a tissue-specific protein-protein interaction network approach. We identified a beta-cell protein-protein interaction module that was significantly enriched for low gene scores based on the GWAS...... P-values and found support at the network level in an independent cohort from Tübingen, Germany (n = 100). Additionally, a polygenic risk score based on SNPs prioritized from the network was associated (P

  4. Activation of PPARd and RXRa stimulates fatty acid oxidatin and insulin secretion inpancreatic beta-cells

    DEFF Research Database (Denmark)

    Børgesen, Michael; Ravnskjær, Kim; Frigerio, Francesca

    as a central effector of unsaturated fatty acids in pancreatic ß-cells. Interestingly, activation of PPARd increases basal as well as glucose-stimulated insulin secretion of INS-1E cells. This increase is further potentiated by RXR agonists. This observation suggests that PPARd may mediate some of the positive......ACTIVATION OF PPARd AND RXRa STIMULATES FATTY ACID OXIDATION AND INSULIN SECRETION IN PANCREATIC b-CELLS Michael Boergesen1, Kim Ravnskjaer2, Francesca Frigerio3, Allan E. Karlsen4, Pierre Maechler3 and Susanne Mandrup1 1 Department of Biochemistry and Molecular Biology, University of Southern...... of genes as PPARd specific agonists and stimulates ß-oxidation. Importantly, oleate-induction of gene expression and ß-oxidation in INS-1E cells is abolished by knock-down of PPARd using adenoviral transfer of shRNA. Thus, PPARd appears to be a central regulator of fatty acid metabolism as well...

  5. Psychological insulin resistance in type 2 diabetes patients regarding oral antidiabetes treatment, subcutaneous insulin injections, or inhaled insulin.

    Science.gov (United States)

    Petrak, Frank; Herpertz, Stephan; Stridde, Elmar; Pfützner, Andreas

    2013-08-01

    "Psychological insulin resistance" (PIR) is an obstacle to insulin treatment in type 2 diabetes, and patients' expectations regarding alternative ways of insulin delivery are poorly understood. PIR and beliefs regarding treatment alternatives were analyzed in patients with type 2 diabetes (n=532; mean glycated hemoglobin, 68±12 mmol/mol [8.34±1.5%]) comparing oral antidiabetes treatment, subcutaneous insulin injections, or inhaled insulin. Questionnaires were used to assess barriers to insulin treatment (BIT), generic and diabetes-specific quality of life (Short Form 36 and Problem Areas in Diabetes, German version), diabetes knowledge, locus of control (Questionnaire for the Assessment of Diabetes-Specific Locus of Control, in German), coping styles (Freiburg Questionnaire of Illness Coping, 15-Items Short Form), self-esteem (Rosenberg Self-Esteem Scale, German version), and mental disorders (Patient Health Questionnaire, German version). Patients discussed treatment optimization options with a physician and were asked to make a choice about future diabetes therapy options in a two-step treatment choice scenario. Step 1 included oral antidiabetes drugs or subcutaneous insulin injection (SCI). Step 2 included an additional treatment alternative of inhaled insulin (INH). Subgroups were analyzed according to their treatment choice. Most patients perceived their own diabetes-related behavior as active, problem-focused, internally controlled, and oriented toward their doctors' recommendations, although their diabetes knowledge was limited. In Step 1, rejection of the recommended insulin was 82%, and in Step 2, it was 57%. Fear of hypoglycemia was the most important barrier to insulin treatment. Patients choosing INH (versus SCI) scored higher regarding fear of injection, expected hardship from insulin therapy, and BIT-Sumscore. The acceptance of insulin is very low in type 2 diabetes patients. The option to inhale insulin increases the acceptability for some but

  6. High serum resistin is associated with an increase in adiposity but not a worsening of insulin resistance in Pima Indians

    DEFF Research Database (Denmark)

    de Courten, Barbora; Degawa-Yamauchi, Mikako; Considine, Robert V

    2004-01-01

    Resistin is an adipokine with putative prodiabetogenic properties. Like other hormones secreted by adipose tissue, resistin is being investigated as a possible etiologic link between excessive adiposity and insulin resistance. Although there is growing evidence that circulating levels...... of this adipokine are proportional to the degree of adiposity, an effect on insulin resistance in humans remains unproven. To evaluate the relations among resistin, obesity, and insulin resistance, we measured fasting serum resistin levels in 113 nondiabetic (75-g oral glucose tolerance test) Pima Indians (ages 29...... +/- 7 years, body fat 31 +/- 8%, resistin 3.7 +/- 1.1 ng/ml [means +/- SD]), who were characterized for body composition (assessed by hydrodensitometry or dual-energy X-ray absorptiometry), whole-body insulin sensitivity (M; assessed by hyperinsulinemic clamp), basal hepatic glucose output (BHGO...

  7. Superoxide generation is diminished during glucose-stimulated insulin secretion in INS-1E cells

    Czech Academy of Sciences Publication Activity Database

    Ježek, Petr; Hlavatá, Lydie; Špaček, Tomáš

    2008-01-01

    Roč. 275, Suppl.1 (2008), s. 310-310 ISSN 1742-464X. [FEBS Congress /33./ and IUBMB Conference /11./. 28.06.2008-03.07.2008, Athens] R&D Projects: GA MZd(CZ) NR7917; GA AV ČR(CZ) IAA500110701 Institutional research plan: CEZ:AV0Z50110509 Keywords : cpo1 * superoxide production * glucose-stimulated insulin secretion * INS-1E cells Subject RIV: ED - Physiology

  8. Dual role of proapoptotic BAD in insulin secretion and beta cell survival

    OpenAIRE

    Danial, Nika N.; Walensky, Loren D.; Zhang, Chen-Yu; Choi, Cheol Soo; Fisher, Jill K.; Molina, Anthony J. A.; Datta, Sandeep Robert; Pitter, Kenneth L.; Bird, Gregory H.; Wikstrom, Jakob D.; Deeney, Jude T.; Robertson, Kirsten; Morash, Joel; Kulkarni, Ameya; Neschen, Susanne

    2008-01-01

    The proapoptotic BCL-2 family member BAD resides in a glucokinase-containing complex that regulates glucose-driven mitochondrial respiration. Here, we present genetic evidence of a physiologic role for BAD in glucose-stimulated insulin secretion by beta cells. This novel function of BAD is specifically dependent upon the phosphorylation of its BH3 sequence, previously defined as an essential death domain. We highlight the pharmacologic relevance of phosphorylated BAD BH3 by using cell-permeab...

  9. Leucine metabolism in regulation of insulin secretion from pancreatic beta cells

    OpenAIRE

    Yang, Jichun; Chi, Yujing; Burkhardt, Brant R.; Guan, Youfei; Wolf, Bryan A

    2010-01-01

    Leucine, a the branched-chain amino acids that must be supplied in daily diet, plays an important role in controlling protein synthesis and regulating cell metabolism in various cell types. In pancreatic β cells, leucine acutely stimulates insulin secretion by serving as both metabolic fuel and allosteric activator of glutamate dehydrogenase to enhance glutaminolysis. Leucine has also been shown to regulate gene transcription and protein synthesis in pancreatic islet β cells via both mTOR-dep...

  10. Insulin secretion and cellular glucose metabolism after prolonged low-grade intralipid infusion in young men

    DEFF Research Database (Denmark)

    Jensen, Christine B; Storgaard, Heidi; Holst, Jens Juul

    2003-01-01

    (HI), 40 mU/m(2) x min], 3-(3)H-glucose, indirect calorimetry, and iv glucose tolerance test. Free fatty acid concentrations were similar during basal steady state but 3.7- to 13-fold higher during clamps. P-glucagon increased and the insulin/glucagon ratio decreased at both LI and HI during...... not in the nonoxidative) glucose metabolism in young healthy men. Moreover, insulin hypersecretion perfectly countered the free-fatty acid-induced insulin resistance. Future studies are needed to determine the role of a prolonged moderate lipid load in subjects at increased risk of developing diabetes....

  11. Higher fetal insulin resistance in Chinese pregnant women with gestational diabetes mellitus and correlation with maternal insulin resistance.

    Directory of Open Access Journals (Sweden)

    Qiuwei Wang

    Full Text Available OBJECTIVE: The aim of this study was to determine the effect of gestational diabetes mellitus (GDM on fetal insulin resistance or β-cell function in Chinese pregnant women with GDM. MEASUREMENTS: Maternal fasting blood and venous cord blood samples (reflecting fetal condition were collected in 65 well-controlled Chinese GDM mothers (only given dietary intervention and 83 control subjects. The insulin, glucose and proinsulin concentrations of both maternal and cord blood samples were measured, and the homeostasis model assessment of insulin resistance (HOMA-IR and the proinsulin-to-insulin ratios (an indicator of fetal β-cell function were calculated in maternal and cord blood respectively. RESULTS: Both maternal and fetal levels of insulin, proinsulin and HOMA-IR but not proinsulin-to-insulin ratios were significantly higher in the GDM group than in the control group (maternal insulin, 24.8 vs. 15.4 µU/mL, P = 0.004, proinsulin, 23.3 vs. 16.2 pmol/L, P = 0.005, and HOMA-IR, 5.5 vs. 3.5, P = 0.041, respectively; fetal: insulin, 15.1 vs. 7.9 µU/mL, P<0.001, proinsulin, 25.8 vs. 15.1 pmol/L, P = 0.015, and HOMA-IR, 2.8 vs. 1.4, P = 0.017, respectively. Fetal HOMA-IR but not proinsulin-to-insulin ratios was significantly correlated to maternal HOMA-IR (r = 0.307, P = 0.019, in the pregnant women with GDM. CONCLUSIONS: Fetal insulin resistance was higher in Chinese pregnant women with GDM than control subjects, and correlated with maternal insulin resistance.

  12. Evidence for altered transport of insulin across the blood-brain barrier in insulin-resistant humans.

    Science.gov (United States)

    Heni, Martin; Schöpfer, Patricia; Peter, Andreas; Sartorius, Tina; Fritsche, Andreas; Synofzik, Matthis; Häring, Hans-Ulrich; Maetzler, Walter; Hennige, Anita M

    2014-08-01

    Eating behavior, body weight regulation, peripheral glucose metabolism, and cognitive function depend on adequate insulin action in the brain, and recent studies in humans suggested that impaired insulin action in the brain emerges upon fat intake, obesity, and genetic variants. As insulin enters into the brain in a receptor-mediated fashion, we hypothesized that whole-body insulin sensitivity might affect the transport of insulin into the brain and contribute to the aversive effect of insulin resistance in the central nervous system. In this study, we aimed to determine the ratio of insulin in the cerebrospinal fluid and serum to whole-body insulin sensitivity. Healthy human subjects participated in an oral glucose tolerance test to determine whole-body insulin sensitivity and underwent lumbar puncture. Blood and CSF concentrations of insulin were significantly correlated. The CSF/serum ratio for insulin was significantly associated with whole body insulin sensitivity with reduced insulin transported into the CSF in insulin-resistant subjects. Together, our data suggest that transport of insulin into the CSF relates to peripheral insulin sensitivity and impairs insulin action in the brain. This underlines the need for sensitizing measures in insulin-resistant subjects.

  13. Childhood obesity and insulin resistance: how should it be managed?

    Science.gov (United States)

    Ho, Mandy; Garnett, Sarah P; Baur, Louise A

    2014-12-01

    Concomitant with the rise in global pediatric obesity in the past decades, there has been a significant increase in the number of children and adolescents with clinical signs of insulin resistance. Given insulin resistance is the important link between obesity and the associated metabolic abnormalities and cardiovascular risk, clinicians should be aware of high risk groups and treatment options. As there is no universally accepted biochemical definition of insulin resistance in children and adolescents, identification and diagnosis of insulin resistance usually relies on clinical features such as acanthosis nigricans, polycystic ovary syndrome, hypertension, dyslipidemia, and nonalcoholic fatty liver disease. Treatment for reducing insulin resistance and other obesity-associated comorbidities should focus on changes in health behaviors to achieve effective weight management. Lifestyle interventions incorporating dietary change, increased physical activity, and decreased sedentary behaviors, with the involvement of family and adoption of a developmentally appropriate approach, should be used as the first line treatment. Current evidence suggests that the primary objective of dietary interventions should be to reduce total energy intake and a combination of aerobic and resistance training should be encouraged. Metformin can be used in conjunction with a lifestyle intervention program in obese adolescents with clinical insulin resistance to achieve weight loss and to improve insulin sensitivity. Ongoing evaluation and research are required to explore optimal protocol and long-term effectiveness of lifestyle interventions, as well as to determine whether the improvements in insulin sensitivity induced by lifestyle interventions and weight loss will lead to a clinical benefit including reduced cardiovascular morbidity and mortality.

  14. Kcne2 deletion impairs insulin secretion and causes type 2 diabetes mellitus.

    Science.gov (United States)

    Lee, Soo Min; Baik, Jasmine; Nguyen, Dara; Nguyen, Victoria; Liu, Shiwei; Hu, Zhaoyang; Abbott, Geoffrey W

    2017-06-01

    Type 2 diabetes mellitus (T2DM) represents a rapidly increasing threat to global public health. T2DM arises largely from obesity, poor diet, and lack of exercise, but it also involves genetic predisposition. Here we report that the KCNE2 potassium channel transmembrane regulatory subunit is expressed in human and mouse pancreatic β cells. Kcne2 deletion in mice impaired glucose tolerance as early as 5 wk of age in pups fed a Western diet, ultimately causing diabetes. In adult mice fed normal chow, skeletal muscle expression of insulin receptor β and insulin receptor substrate 1 were down-regulated 2-fold by Kcne2 deletion, characteristic of T2DM. Kcne2 deletion also caused extensive pancreatic transcriptome changes consistent with facets of T2DM, including endoplasmic reticulum stress, inflammation, and hyperproliferation. Kcne2 deletion impaired β-cell insulin secretion in vitro up to 8-fold and diminished β-cell peak outward K + current at positive membrane potentials, but also left-shifted its voltage dependence and slowed inactivation. Interestingly, we also observed an aging-dependent reduction in β-cell outward currents in both Kcne2 +/+ and Kcne2 - / - mice. Our results demonstrate that KCNE2 is required for normal β-cell electrical activity and insulin secretion, and that Kcne2 deletion causes T2DM. KCNE2 may regulate multiple K + channels in β cells, including the T2DM-linked KCNQ1 potassium channel α subunit.-Lee, S. M., Baik, J., Nguyen, D., Nguyen, V., Liu, S., Hu, Z., Abbott, G. W. Kcne2 deletion impairs insulin secretion and causes type 2 diabetes mellitus. © FASEB.

  15. Reactive oxygen species as a signal in glucose-stimulated insulin secretion.

    Science.gov (United States)

    Pi, Jingbo; Bai, Yushi; Zhang, Qiang; Wong, Victoria; Floering, Lisa M; Daniel, Kiefer; Reece, Jeffrey M; Deeney, Jude T; Andersen, Melvin E; Corkey, Barbara E; Collins, Sheila

    2007-07-01

    One of the unique features of beta-cells is their relatively low expression of many antioxidant enzymes. This could render beta-cells susceptible to oxidative damage but may also provide a system that is sensitive to reactive oxygen species as signals. In isolated mouse islets and INS-1(832/13) cells, glucose increases intracellular accumulation of H2O2. In both models, insulin secretion could be stimulated by provision of either exogenous H2O2 or diethyl maleate, which raises intracellular H2O2 levels. Provision of exogenous H2O2 scavengers, including cell permeable catalase and N-acetyl-L-cysteine, inhibited glucose-stimulated H2O2 accumulation and insulin secretion (GSIS). In contrast, cell permeable superoxide dismutase, which metabolizes superoxide into H2O2, had no effect on GSIS. Because oxidative stress is an important risk factor for beta-cell dysfunction in diabetes, the relationship between glucose-induced H2O2 generation and GSIS was investigated under various oxidative stress conditions. Acute exposure of isolated mouse islets or INS-1(832/13) cells to oxidative stressors, including arsenite, 4-hydroxynonenal, and methylglyoxal, led to decreased GSIS. This impaired GSIS was associated with increases in a battery of endogenous antioxidant enzymes. Taken together, these findings suggest that H2O2 derived from glucose metabolism is one of the metabolic signals for insulin secretion, whereas oxidative stress may disturb its signaling function.

  16. Geniposide regulates glucose-stimulated insulin secretion possibly through controlling glucose metabolism in INS-1 cells.

    Directory of Open Access Journals (Sweden)

    Jianhui Liu

    Full Text Available Glucose-stimulated insulin secretion (GSIS is essential to the control of metabolic fuel homeostasis. The impairment of GSIS is a key element of β-cell failure and one of causes of type 2 diabetes mellitus (T2DM. Although the KATP channel-dependent mechanism of GSIS has been broadly accepted for several decades, it does not fully describe the effects of glucose on insulin secretion. Emerging evidence has suggested that other mechanisms are involved. The present study demonstrated that geniposide enhanced GSIS in response to the stimulation of low or moderately high concentrations of glucose, and promoted glucose uptake and intracellular ATP levels in INS-1 cells. However, in the presence of a high concentration of glucose, geniposide exerted a contrary role on both GSIS and glucose uptake and metabolism. Furthermore, geniposide improved the impairment of GSIS in INS-1 cells challenged with a high concentration of glucose. Further experiments showed that geniposide modulated pyruvate carboxylase expression and the production of intermediates of glucose metabolism. The data collectively suggest that geniposide has potential to prevent or improve the impairment of insulin secretion in β-cells challenged with high concentrations of glucose, likely through pyruvate carboxylase mediated glucose metabolism in β-cells.

  17. The gut microbiota, obesity and insulin resistance.

    Science.gov (United States)

    Shen, Jian; Obin, Martin S; Zhao, Liping

    2013-02-01

    The human gut is densely populated by commensal and symbiotic microbes (the "gut microbiota"), with the majority of the constituent microorganisms being bacteria. Accumulating evidence indicates that the gut microbiota plays a significant role in the development of obesity, obesity-associated inflammation and insulin resistance. In this review we discuss molecular and cell biological mechanisms by which the microbiota participate in host functions that impact the development and maintenance of the obese state, including host ingestive behavior, energy harvest, energy expenditure and fat storage. We additionally explore the diverse signaling pathways that regulate gut permeability and bacterial translocation to the host and how these are altered in the obese state to promote the systemic inflammation ("metabolic endotoxemia") that is a hallmark of obesity and its complications. Fundamental to our discussions is the concept of "crosstalk", i.e., the biochemical exchange between host and microbiota that maintains the metabolic health of the superorganism and whose dysregulation is a hallmark of the obese state. Differences in community composition, functional genes and metabolic activities of the gut microbiota appear to distinguish lean vs obese individuals, suggesting that gut 'dysbiosis' contributes to the development of obesity and/or its complications. The current challenge is to determine the relative importance of obesity-associated compositional and functional changes in the microbiota and to identify the relevant taxa and functional gene modules that promote leanness and metabolic health. As diet appears to play a predominant role in shaping the microbiota and promoting obesity-associated dysbiosis, parallel initiatives are required to elucidate dietary patterns and diet components (e.g., prebiotics, probiotics) that promote healthy gut microbiota. How the microbiota promotes human health and disease is a rich area of investigation that is likely to generate

  18. Effect of cigarette smoking on insulin resistance risk.

    Science.gov (United States)

    Haj Mouhamed, D; Ezzaher, A; Neffati, F; Douki, W; Gaha, L; Najjar, M F

    2016-02-01

    Smoking is one of the main risk factors for cardiovascular disease (CVD). The mechanism(s) of the effects of smoking on CVD are not clearly understood; however, a number of atherogenic characteristics, such as insulin resistance have been reported. We aim to investigate the effects of cigarette smoking on insulin resistance and to determine the correlation between this parameter with smoking status characteristics. This study was conducted on 138 non-smokers and 162 smokers aged respectively 35.6±16.0 and 38.5±21.9 years. All subjects are not diabetic. Fasting glucose was determined by enzymatic methods and insulin by chemiluminescence method. Insulin resistance (IR) was estimated using the Homeostasis Model of Assessment equation: HOMA-IR=[fasting insulin (mU/L)×fasting glucose (mmol/L)]/22.5. IR was defined as the upper quartile of HOMA-IR. Values above 2.5 were taken as abnormal and reflect insulin resistance. Compared to non-smokers, smokers had significantly higher levels of fasting glucose, fasting insulin and HOMA-IR index. These associations remained significant after adjustment for confounding factors (age, gender, BMI and alcohol consumption). A statistically significant association was noted between the smoking status parameters, including both the number of cigarettes smoked/day and the duration of smoking, and fasting insulin levels as well for HOMA-IR index. Among smokers, we noted a positive correlation between HOMA-IR index and both plasma thiocyanates and urinary cotinine. Our results show that smokers have a high risk to developing an insulin resistance and hyperinsulinemia, compared with a matched group of non-smokers, and may help to explain the high risk of cardiovascular diseases in smokers. Copyright © 2015. Published by Elsevier SAS.

  19. Improvement of insulin secretion in rat models of diabetes after ACEI/ARB therapy

    International Nuclear Information System (INIS)

    Tian Jingyan; Li Fengying; Liu Yun; Long Hongmei; Li Weiyi; Wang Xiao; Zhang Hongli; Li Guo; Luo Min

    2009-01-01

    Objective To study the effect of ACEI/ARB therapy on the secretion of insulin and glucagon as well as serum lipid peroxidation marker 8-iso PGF-2α levels in streptozoticin (STZ) induced diabetic rat models.Methods Twenty-four rat models of STZ induced diabetes were prepared (random blood sugar>16.7 mmol/L). Of which, 8 models were fed enalaprial 5mg/kg/d, 8 models were fed losartan 10μg/kg/d and 8 models left unterated. Fasting serum insulin,glucagon (with RIA) and 8-iso PGF-2α (with ELISA) levels were measured in these models and 8 control rats three weeks later. Intravenous glucose tolerance test (IVGTT) were performed in 12 rats (3 animals in each group) six weeks later. Results: Serum levels of insulin in the treated models were higher than those in the non-treated models but without significance (P>0.05). Serum levels of glucagon and 8-iso PGF-2α levels in the treated models were significantly lower than those in the non-treated models (P 6 x ) in the treated models. Conclusion: ACEI/ARB treatment could improve the secretion of insulin in rat models of diabetes, which might be beneficial for controlling the progression of the disease. This phenomenon is consistent with the result of clinical study. (authors)

  20. Delta-like Ligand-4-Notch Signaling Inhibition Regulates Pancreatic Islet Function and Insulin Secretion

    Directory of Open Access Journals (Sweden)

    Fabienne Billiard

    2018-01-01

    Full Text Available Although Notch signaling has been proposed as a therapeutic target for type-2 diabetes, liver steatosis, and atherosclerosis, its direct effect on pancreatic islets remains unknown. Here, we demonstrated a function of Dll4-Notch signaling inhibition on the biology of insulin-producing cells. We confirmed enhanced expression of key Notch signaling genes in purified pancreatic islets from diabetic NOD mice and showed that treatment with anti-Dll4 antibody specifically abolished Notch signaling pathway activation. Furthermore, we showed that Notch inhibition could drive proliferation of β-islet cells and confer protection from the development of STZ-induced diabetes. Importantly, inhibition of the Dll4 pathway in WT mice increased insulin secretion by inducing the differentiation of pancreatic β-islet cell progenitors, as well as the proliferation of insulin-secreting cells. These findings reveal a direct effect of Dll4-blockade on pancreatic islets that, in conjunction with its immunomodulatory effects, could be used for unmet medical needs hallmarked by inefficient insulin action.

  1. Retinol-Binding Protein 4 and Insulin Resistance in Polycystic Ovary Syndrome

    OpenAIRE

    Hutchison, Samantha K.; Harrison, Cheryce; Stepto, Nigel; Meyer, Caroline; Teede, Helena J.

    2008-01-01

    OBJECTIVE?Polycystic ovary syndrome (PCOS) is an insulin-resistant state with insulin resistance being an established therapeutic target; however, measurement of insulin resistance remains challenging. We aimed to 1) determine serum retinol-binding protein 4 (RBP4) levels (purported to reflect insulin resistance) in women with PCOS and control subjects, 2) examine the relationship of RBP4 to conventional markers of insulin resistance, and 3) examine RBP4 changes with interventions modulating ...

  2. Role of nutrition in preventing insulin resistance in children.

    Science.gov (United States)

    Blasetti, Annalisa; Franchini, Simone; Comegna, Laura; Prezioso, Giovanni; Chiarelli, Francesco

    2016-03-01

    Nutrition during prenatal, early postnatal and pubertal period is crucial for the development of insulin resistance and its consequences. During prenatal period fetal environment and nutrition seems to interfere with metabolism programming later in life. The type of dietary carbohydrates, glycemic index, protein, fat and micronutrient content in maternal nutrition could influence insulin sensitivity in the newborn. The effects of lactation on metabolism and nutritional behavior later in life have been studied. Dietary habits and quality of diet during puberty could prevent the onset of a pathological insulin resistance through an adequate distribution of macro- and micronutrients, a diet rich in fibers and vegetables and poor in saturated fats, proteins and sugars. We want to overview the latest evidences on the risk of insulin resistance later in life due to both nutritional behaviors and components during the aforementioned periods of life, following a chronological outline from fetal development to adolescence.

  3. Effect of daily consumption of probiotic yoghurt on insulin resistance in pregnant women: a randomized controlled trial.

    Science.gov (United States)

    Asemi, Z; Samimi, M; Tabassi, Z; Naghibi Rad, M; Rahimi Foroushani, A; Khorammian, H; Esmaillzadeh, A

    2013-01-01

    Owing to excess body weight and increased secretion of inflammatory cytokines primarily during the third trimester, pregnancy is associated with elevated insulin resistance. To our knowledge, no report is available indicating the effects of probiotic yoghurt consumption on serum insulin levels in pregnant women. This study was designed to determine the effects of daily consumption of probiotic yoghurt on insulin resistance and serum insulin levels of Iranian pregnant women. In this randomized controlled clinical trial, 70 primigravida pregnant women with singleton pregnancy at their third trimester were participated. We randomly assigned participants to consume 200 g per day of conventional (n=33) or the probiotic group (n=37) for 9 weeks. The probiotic yoghurt was a commercially available product prepared with the starter cultures of Streptococcus thermophilus and Lactobacillus bulgaricus, enriched with probiotic culture of two strains of lactobacilli (Lactobacillus acidophilus LA5) and bifidobacteria (Bifidobacterium animalis BB12) with a total of min 1 × 10⁷ colony-forming units. Fasting blood samples were taken at baseline and after 9-week intervention to measure fasting plasma glucose and serum insulin levels. Homeostatic model assessment of insulin resistance (HOMA-IR) was used to calculate insulin resistance score. Although consumption of probiotic yogurt for 9 weeks did not affect serum insulin levels and HOMA-IR score, significant differences were found comparing changes in these variables between probiotic and conventional yogurts (changes from baseline in serum insulin levels: +1.2±1.2 vs +5.0±1.1 μIU/ml, respectively, P=0.02; and in HOMA-IR score: -0.2±0.3 vs 0.7±0.2, respectively, P=0.01). It is concluded that in contrast to conventional yogurt, daily consumption of probiotic yogurt for 9 weeks maintains serum insulin levels and might help pregnant women prevent developing insulin resistance.

  4. DHEA supplementation in ovariectomized rats reduces impaired glucose-stimulated insulin secretion induced by a high-fat diet

    Directory of Open Access Journals (Sweden)

    Katherine Veras

    2014-01-01

    Full Text Available Dehydroepiandrosterone (DHEA and the dehydroepiandrosterone sulfate (DHEA-S are steroids produced mainly by the adrenal cortex. There is evidence from both human and animal models suggesting beneficial effects of these steroids for obesity, diabetes mellitus, hypertension, and osteoporosis, conditions associated with the post-menopausal period. Accordingly, we hypothesized that DHEA supplementation in ovariectomized (OVX female rats fed a high-fat diet would maintain glucose-induced insulin secretion (GSIS and pancreatic islet function. OVX resulted in a 30% enlargement of the pancreatic islets area compared to the control rats, which was accompanied by a 50% reduction in the phosphorylation of AKT protein in the pancreatic islets. However, a short-term high-fat diet induced insulin resistance, accompanied by impaired GSIS in isolated pancreatic islets. These effects were reversed by DHEA treatment, with improved insulin sensitivity to levels similar to the control group, and with increased serine phosphorylation of the AKT protein. These data confirm the protective effect of DHEA on the endocrine pancreas in a situation of diet-induced overweight and low estrogen concentrations, a phenotype similar to that of the post-menopausal period.

  5. Whole-blood viscosity and the insulin-resistance syndrome.

    Science.gov (United States)

    Høieggen, A; Fossum, E; Moan, A; Enger, E; Kjeldsen, S E

    1998-02-01

    In a previous study we found that elevated blood viscosity was linked to the insulin resistance syndrome, and we proposed that high blood viscosity may increase insulin resistance. That study was based on calculated viscosity. To determine whether directly measured whole-blood viscosity was related to the insulin-resistance syndrome in the same way as calculated viscosity had been found to be. Healthy young men were examined with the hyperinsulinemic isoglycemic glucose clamp technique, and we related insulin sensitivity (glucose disposal rate) to other metabolic parameters and to blood viscosity. We established a technique for direct measurement of whole-blood viscosity. There were statistically significant negative correlations between glucose disposal rate and whole-blood viscosity at low and high shear rates (r = -0.41, P = 0.007 for both, n = 42). Whole-blood viscosity was correlated positively (n = 15) to serum triglyceride (r = 0.54, P = 0.04) and total cholesterol (r = 0.52, P = 0.05), and negatively with high-density lipoprotein cholesterol (r = -0.53, P = 0.04) concentrations. Insulin sensitivity index was correlated positively to high-density lipoprotein cholesterol (r = 0.54, P = 0.04) and negatively to serum triglyceride (r = -0.69, P = 0.005) and to total cholesterol (r = -0.81, P = 0.0003) concentrations. The present results demonstrate for the first time that there is a negative relationship between directly measured whole-blood viscosity and insulin sensitivity as a part of the insulin-resistance syndrome. Whole-blood viscosity contributes to the total peripheral resistance, and these results support the hypothesis that insulin resistance has a hemodynamic basis.

  6. 92 INSULIN RESISTANCE: CAUSES AND METABOLIC ...

    African Journals Online (AJOL)

    drclement

    2009-12-01

    Dec 1, 2009 ... Edo State Institute of Technology and Management. Usen, Edo State ... type 2 diabetes mellitus. The cause of the vast ... Insulin (molecular mass 6000D) consists of 51 amino acids .... Experimental Biology and. Medicine 2004 ...

  7. Dietary Anthocyanins and Insulin Resistance: When Food Becomes a Medicine.

    Science.gov (United States)

    Belwal, Tarun; Nabavi, Seyed Fazel; Nabavi, Seyed Mohammad; Habtemariam, Solomon

    2017-10-12

    Insulin resistance is an abnormal physiological state that occurs when insulin from pancreatic β-cells is unable to trigger a signal transduction pathway in target organs such as the liver, muscles and adipose tissues. The loss of insulin sensitivity is generally associated with persistent hyperglycemia (diabetes), hyperinsulinemia, fatty acids and/or lipid dysregulation which are often prevalent under obesity conditions. Hence, insulin sensitizers are one class of drugs currently employed to treat diabetes and associated metabolic disorders. A number of natural products that act through multiple mechanisms have also been identified to enhance insulin sensitivity in target organs. One group of such compounds that gained interest in recent years are the dietary anthocyanins. Data from their in vitro, in vivo and clinical studies are scrutinized in this communication to show their potential health benefit through ameliorating insulin resistance. Specific mechanism of action ranging from targeting specific signal transduction receptors/enzymes to the general antioxidant and anti-inflammatory mechanisms of insulin resistance are presented.

  8. Interleukin-6 induces impairment in human subcutaneous adipogenesis in obesity-associated insulin resistance.

    Science.gov (United States)

    Almuraikhy, Shamma; Kafienah, Wael; Bashah, Moataz; Diboun, Ilhame; Jaganjac, Morana; Al-Khelaifi, Fatima; Abdesselem, Houari; Mazloum, Nayef A; Alsayrafi, Mohammed; Mohamed-Ali, Vidya; Elrayess, Mohamed A

    2016-11-01

    A subset of obese individuals remains insulin sensitive by mechanisms as yet unclear. The hypothesis that maintenance of normal subcutaneous (SC) adipogenesis accounts, at least partially, for this protective phenotype and whether it can be abrogated by chronic exposure to IL-6 was investigated. Adipose tissue biopsies were collected from insulin-sensitive (IS) and insulin-resistant (IR) individuals undergoing weight-reduction surgery. Adipocyte size, pre-adipocyte proportion of stromal vascular fraction (SVF)-derived cells, adipogenic capacity and gene expression profiles of isolated pre-adipocytes were determined, along with local in vitro IL-6 secretion. Adipogenic capacity was further assessed in response to exogenous IL-6 application. Despite being equally obese, IR individuals had significantly lower plasma leptin and adiponectin levels and higher IL-6 levels compared with age-matched IS counterparts. Elevated systemic IL-6 in IR individuals was associated with hyperplasia of adipose tissue-derived SVF cells, despite higher frequency of hypertrophied adipocytes. SC pre-adipocytes from these tissues exhibited lower adipogenic capacity accompanied by downregulation of PPARγ (also known as PPARG) and CEBPα (also known as CEBPA) and upregulation of GATA3 expression. Impaired adipogenesis in IR individuals was further associated with increased adipose secretion of IL-6. Treatment of IS-derived SC pre-adipocytes with IL-6 reduced their adipogenic capacity to levels of the IR group. Obesity-associated insulin resistance is marked by impaired SC adipogenesis, mediated, at least in a subset of individuals, by elevated local levels of IL-6. Understanding the molecular mechanisms underlying reduced adipogenic capacity in IR individuals could help target appropriate therapeutic strategies aimed at those at greatest risk of insulin resistance and type 2 diabetes mellitus.

  9. Third Exposure to a Reduced Carbohydrate Meal Lowers Evening Postprandial Insulin and GIP Responses and HOMA-IR Estimate of Insulin Resistance.

    Science.gov (United States)

    Lin, Po-Ju; Borer, Katarina T

    2016-01-01

    Postprandial hyperinsulinemia, hyperglycemia, and insulin resistance increase the risk of type 2 diabetes (T2D) and cardiovascular disease mortality. Postprandial hyperinsulinemia and hyperglycemia also occur in metabolically healthy subjects consuming high-carbohydrate diets particularly after evening meals and when carbohydrate loads follow acute exercise. We hypothesized the involvement of dietary carbohydrate load, especially when timed after exercise, and mediation by the glucose-dependent insulinotropic peptide (GIP) in this phenomenon, as this incretin promotes insulin secretion after carbohydrate intake in insulin-sensitive, but not in insulin-resistant states. Four groups of eight metabolically healthy weight-matched postmenopausal women were provided with three isocaloric meals (a pre-trial meal and two meals during the trial day) containing either 30% or 60% carbohydrate, with and without two-hours of moderate-intensity exercise before the last two meals. Plasma glucose, insulin, glucagon, GIP, glucagon-like peptide 1 (GLP-1), free fatty acids (FFAs), and D-3-hydroxybutyrate concentrations were measured during 4-h postprandial periods and 3-h exercise periods, and their areas under the curve (AUCs) were analyzed by mixed-model ANOVA, and insulin resistance during fasting and meal tolerance tests within each diet was estimated using homeostasis-model assessment (HOMA-IR). The third low-carbohydrate meal, but not the high-carbohydrate meal, reduced: (1) evening insulin AUC by 39% without exercise and by 31% after exercise; (2) GIP AUC by 48% without exercise and by 45% after exercise, and (3) evening insulin resistance by 37% without exercise and by 24% after exercise. Pre-meal exercise did not alter insulin-, GIP- and HOMA-IR- lowering effects of low-carbohydrate diet, but exacerbated evening hyperglycemia. Evening postprandial insulin and GIP responses and insulin resistance declined by over 30% after three meals that limited daily carbohydrate intake to

  10. The loss of Sirt1 in mouse pancreatic beta cells impairs insulin secretion by disrupting glucose sensing

    DEFF Research Database (Denmark)

    Luu, L; Dai, F F; Prentice, K J

    2013-01-01

    Sirtuin 1 (SIRT1) has emerged as a key metabolic regulator of glucose homeostasis and insulin secretion. Enhanced SIRT1 activity has been shown to be protective against diabetes, although the mechanisms remain largely unknown. The aim of this study was to determine how SIRT1 regulates insulin sec...

  11. C-Peptide, Baseline and Postprandial Insulin Resistance after a Carbohydrate-Rich Test Meal - Evidence for an Increased Insulin Clearance in PCOS Patients?

    Science.gov (United States)

    Stassek, J; Erdmann, J; Ohnolz, F; Berg, F D; Kiechle, M; Seifert-Klauss, V

    2017-01-01

    Introduction Known characteristics of patients with PCOS include infertility, menstrual disorders, hirsutism and also often insulin resistance. These symptoms increase with increasing body weight. In the LIPCOS study ( L ifestyle I ntervention for Patients with Polycystic Ovary Syndrome [ PCOS ]) long-term changes of the PCOS in dependence on pregnancy and parenthood were systematically assessed. In the framework of the LIPCOS study, PCOS patients were given a standardised carbohydrate-rich test meal in order to examine glucose homeostasis and insulin secretion. The results were compared with those of a eumenorrhoeic control group who all had corresponding BMI values and corresponding ages. Methods and Patients 41 PCOS patients (without diabetes) and 68 controls received a standardised carbohydrate-rich test meal (260 kcal, 62 % carbohydrates, 32 % fat, 6 % proteins) in order to generate a submaximal insulin and glucose stimulation. The values were determined at baseline and postprandial after 60, 120 and 180 minutes. In addition, the corresponding C-peptide levels were recorded. Results In the PCOS patients (n = 41), the insulin secretion test after a standardised test meal showed almost identical baseline and postprandial insulin levels when compared with those of the age- and BMI-matched eumenorrhoeic controls (n = 68). In the PCOS patients, the baseline and postprandial glucose levels were significantly elevated (92.88 ± 10.28 [PCOS] vs. 85.07 ± 9.42 mg/dL [controls]; p PCOS patients formally exhibit a higher fasting insulin resistance than controls. In spite of the higher stimulated C-peptide levels, the insulin levels did not increase more strongly with increasing glucose levels than in controls which may be indicative of a higher insulin clearance in PCOS patients.

  12. Glucagon-Like Peptide 1 Recruits Muscle Microvasculature and Improves Insulin’s Metabolic Action in the Presence of Insulin Resistance

    Science.gov (United States)

    Chai, Weidong; Zhang, Xingxing; Barrett, Eugene J.

    2014-01-01

    Glucagon-like peptide 1 (GLP-1) acutely recruits muscle microvasculature, increases muscle delivery of insulin, and enhances muscle use of glucose, independent of its effect on insulin secretion. To examine whether GLP-1 modulates muscle microvascular and metabolic insulin responses in the setting of insulin resistance, we assessed muscle microvascular blood volume (MBV), flow velocity, and blood flow in control insulin-sensitive rats and rats made insulin-resistant acutely (systemic lipid infusion) or chronically (high-fat diet [HFD]) before and after a euglycemic-hyperinsulinemic clamp (3 mU/kg/min) with or without superimposed systemic GLP-1 infusion. Insulin significantly recruited muscle microvasculature and addition of GLP-1 further expanded muscle MBV and increased insulin-mediated glucose disposal. GLP-1 infusion potently recruited muscle microvasculature in the presence of either acute or chronic insulin resistance by increasing muscle MBV. This was associated with an increased muscle delivery of insulin and muscle interstitial oxygen saturation. Muscle insulin sensitivity was completely restored in the presence of systemic lipid infusion and significantly improved in rats fed an HFD. We conclude that GLP-1 infusion potently expands muscle microvascular surface area and improves insulin’s metabolic action in the insulin-resistant states. This may contribute to improved glycemic control seen in diabetic patients receiving incretin-based therapy. PMID:24658303

  13. Association of insulin resistance with obesity in children

    International Nuclear Information System (INIS)

    Siddiqui, S.A.; Bashir, S.; Shabbir, I.; Sherwani, M.K.; Aasim, M.

    2011-01-01

    Background: Insulin resistance is the primary metabolic disorder associated with obesity. Little is known about its role as a determinant of the metabolic syndrome in obese children. Objectives: To assess the association of insulin resistance with metabolic syndrome in obese and non obese children. Study type and settings: Cross sectional analytical study conducted among children of ten Municipal Corporation high schools of Data Ganj Buksh Town Lahore. Subjects and Methods: A total of 46 obese and 49 non obese children with consent were recruited for the study. Fasting blood glucose, serum insulin, high density lipoprotein in cholesterol, triglycerides, cholesterol, non HDL-cholesterol LDL-cholesterol were measured using standard methods. Data were analyzed by using statistical software SPSS-Version 15. Results: A total of 95 children 49 obese and 46 non obese were recruited for the study. A significant association of serum triglyceride(p<0.001), high density lipoprotein cholesterol(p<0.001), fasting blood glucose(p<0.001), and insulin levels (p<0.001) , was seen between the two groups. For each component of metabolic syndrome, when insulin resistance increased so did odds ratios for cardio metabolic risk factors. Conclusions: Insulin resistance was seen in 34.7% children. Metabolic syndrome was found in 31.6% children reflecting that obese children are at high risk for metabolic syndrome and have low HDL-cholesterol and high triglycerides levels. (author)

  14. The emerging role of incretins in the pathophysiology of insulin resistance in type 1 diabetes.

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    Gorana Mirošević

    2017-09-01

    Full Text Available The pathophysiology of insulin resistance (IR comprises a complex adipokine-mediated crosstalk between white adipose tissue and other organs. Although it is a prominent feature of Type 2 diabetes, a certain degree of IR also exists in Type 1 diabetes mellitus (T1DM. Incretins are gut derived hormones secreted into the circulation in response to nutrient ingestion that enhances glucose-stimulated insulin secretion. One of the main incretin hormones is glucagon-like peptide-1. It is degraded by dipeptidyl peptidase-4 (DPP-4 minutes after secretion. The diminished “incretin effect” is recognized as a part of prediabetes, usually associated with IR. DPP-4, as a part of the incretin system, has recently been proposed as a novel adipokine linked to IR and DPP-4 activity is higher in T1DM patients compared to healthy controls; furthermore, it correlates with the degree of IR. The role of the incretin system, with special emphasis on DPP-4, merits further evaluation because it might offer an insulin add-on therapeutic approach in the metabolic control of T1DM.

  15. Insulin Secretion and Incretin Hormone Concentration in Women with Previous Gestational Diabetes Mellitus

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    Sung Hoon Yu

    2011-02-01

    Full Text Available BackgroundWe examined the change in the levels of incretin hormone and effects of glucose-dependent insulinotropic polypeptide (GIP and glucagon-like peptide 1 (GLP-1 on insulin secretion in women with previous gestational diabetes (pGDM.MethodsA 75-g oral glucose tolerance test (OGTT was conducted on 34 women with pGDM. In addition, 11 women with normal glucose tolerance, matched for age, height and weight, were also tested. The insulin, GIP, GLP-1, and glucagon concentrations were measured, and their anthropometric and biochemical markers were also measured.ResultsAmong 34 women with pGDM, 18 had normal glucose tolerance, 13 had impaired glucose tolerance (IGT and 1 had diabetes. No significant differences were found in GLP-1 concentration between the pGDM and control group. However, a significantly high level of glucagon was present in the pGDM group at 30 minutes into the OGTT. The GIP concentration was elevated at 30 minutes and 60 minutes in the pGDM group. With the exception of the 30-minute timepoint, women with IGT had significantly high blood glucose from 0 to 120 minutes. However, there was no significant difference in insulin or GLP-1 concentration. The GIP level was significantly high from 0 to 90 minutes in patients diagnosed with IGT.ConclusionGLP-1 secretion does not differ between pGDM patients and normal women. GIP was elevated, but that does not seem to induce in increase in insulin secretion. Therefore, we conclude that other factors such as heredity and environment play important roles in the development of type 2 diabetes.

  16. Homeostatic model assessment for insulin resistance (homa-ir): a better marker for evaluating insulin resistance than fasting insulin in women with polycystic ovarian syndrome

    International Nuclear Information System (INIS)

    Majid, H.; Khan, A.H.; Masood, Q.

    2017-01-01

    To assess the utility of HOMA-IR in assessing insulin resistance in patients with polycystic ovary syndrome (PCOS) and compare it with fasting insulin for assessing insulin resistance (IR). Study Design: Observational study. Place and Duration of Study: Section of Clinical Chemistry, Department of Pathology and Laboratory Medicine, The Aga Khan University Hospital, Karachi, from January 2009 to September 2012. Methodology: Medical chart review of all women diagnosed with PCOS was performed. Of the 400 PCOS women reviewed, 91 met the inclusion criteria. Insulin resistance was assessed by calculating HOMA-IR using the formula (fasting glucose x fasting insulin)/405, taking normal value =12 micro IU/ml. Results: A total of 91 premenopausal women diagnosed with PCOS were included. Mean age was 30 +-5.5 years. Mean HOMA-IR of women was 3.1 +-1.7, respectively with IR in 69% (n=63) women, while hyperinsulinemia was present in 60% (n=55) women (fasting Insulin 18.5 +-5.8 micro IU/ml). Hyperandrogenism was present in 53.8% (n=49), whereas 38.5% (n=35) women had primary infertility or subfertility, while 65.9% (n=60) had menstrual irregularities; and higher frequencies were observed in women with IR. Eight subjects with IR and endocrine abnormalities were missed by fasting insulin. Conclusion: Insulin resistance is common in PCOS and it is likely a pathogenic factor for development of PCOS. HOMA-IR model performed better than hyperinsulinemia alone for diagnosing IR. (author)

  17. Homeostatic Model Assessment for Insulin Resistance (HOMA-IR): A Better Marker for Evaluating Insulin Resistance Than Fasting Insulin in Women with Polycystic Ovarian Syndrome.

    Science.gov (United States)

    Majid, Hafsa; Masood, Qamar; Khan, Aysha Habib

    2017-03-01

    To assess the utility of HOMA-IR in assessing insulin resistance in patients with polycystic ovary syndrome (PCOS) and compare it with fasting insulin for assessing insulin resistance (IR). Observational study. Section of Clinical Chemistry, Department of Pathology and Laboratory Medicine, The Aga Khan University Hospital, Karachi, from January 2009 to September 2012. Medical chart review of all women diagnosed with PCOS was performed. Of the 400 PCOS women reviewed, 91 met the inclusion criteria. Insulin resistance was assessed by calculating HOMA-IR using the formula (fasting glucose x fasting insulin)/405, taking normal value HOMA-IR of women was 3.1 ±1.7, respectively with IR in 69% (n=63) women, while hyperinsulinemia was present in 60% (n=55) women (fasting Insulin 18.5 ±5.8 µIU/ml). Hyperandrogenism was present in 53.8% (n=49), whereas 38.5% (n=35) women had primary infertility or subfertility, while 65.9% (n=60) had menstrual irregularities; and higher frequencies were observed in women with IR. Eight subjects with IR and endocrine abnormalities were missed by fasting insulin. Insulin resistance is common in PCOS and it is likely a pathogenic factor for development of PCOS. HOMAIR model performed better than hyperinsulinemia alone for diagnosing IR.

  18. Explaining psychological insulin resistance in adults with non-insulin-treated type 2 diabetes

    DEFF Research Database (Denmark)

    Holmes-Truscott, Elizabeth; Skinner, Timothy Chas; Pouwer, F

    2016-01-01

    to the model. CONCLUSIONS: Psychological insulin resistance may reflect broader distress about diabetes and concerns about its treatment but not general beliefs about medicines, depression or anxiety. Reducing diabetes distress and current treatment concerns may improve attitudes towards insulin as a potential......AIMS: To investigate the contribution of general and diabetes-specific emotional wellbeing and beliefs about medicines in the prediction of insulin therapy appraisals in adults with non-insulin-treated type 2 diabetes. METHODS: The sample included Diabetes MILES-Australia cross-sectional survey...... diabetes medications (BMQ Specific); negative insulin therapy appraisals (ITAS); depression (PHQ-9); anxiety (GAD-7), and diabetes distress (DDS-17). Factors associated with ITAS Negative scores were examined using hierarchical multiple regressions. RESULTS: Twenty-two percent of the variance in ITAS...

  19. Effects of the beta-carbolines, harmane and pinoline, on insulin secretion from isolated human islets of Langerhans.

    Science.gov (United States)

    Cooper, E Jane; Hudson, Alan L; Parker, Christine A; Morgan, Noel G

    2003-12-15

    It is well known that certain imidazoline compounds can stimulate insulin secretion and this has been attributed to the activation of imidazoline I(3) binding sites in the pancreatic beta-cell. Recently, it has been proposed that beta-carbolines may be endogenous ligands having activity at imidazoline sites and we have, therefore, studied the effects of beta-carbolines on insulin secretion. The beta-carbolines harmane, norharmane and pinoline increased insulin secretion two- to threefold from isolated human islets of Langerhans. The effects of harmane and pinoline were dose-dependent (EC(50): 5 and 25 microM, respectively) and these agents also blocked the inhibitory effects of the potassium channel agonist, diazoxide, on glucose-induced insulin release. Stimulation of insulin secretion by harmane was glucose-dependent but, unlike the imidazoline I(3) receptor agonist efaroxan, it increased the rate of insulin release beyond that elicited by 20 mM glucose (20 mM glucose alone: 253+/-34% vs. basal; 20 mM glucose plus 100 microM harmane: 327+/-15%; P<0.01). Stimulation of insulin secretion by harmane was attenuated by the imidazoline I(3) receptor antagonist KU14R (2 (2-ethyl 2,3-dihydro-2-benzofuranyl)-2-imidazole) and was reduced when islets were treated with efaroxan for 18 h, prior to the addition of harmane. The results reveal that beta-carbolines can potentiate the rate of insulin secretion from human islets and suggest that these agents may be useful prototypes for the development of novel insulin secretagogues.

  20. Longitudinal Changes in Insulin Resistance, Beta-Cell Function and Glucose Regulation Status in Prediabetes.

    Science.gov (United States)

    Kim, Chul-Hee; Kim, Hong-Kyu; Kim, Eun-Hee; Bae, Sung-Jin; Choe, Jaewon; Park, Joong-Yeol

    2018-01-01

    The changes in insulin resistance and insulin secretion and their association with changes in glucose regulation status in Asians with prediabetes remain uncertain. We included Korean adults (aged 20-79 years) with prediabetes who underwent routine medical check-ups at a mean interval of 5 years. Prediabetes was defined as fasting plasma glucose (FPG) 5.6-6.9mmol/l or HbA1c 5.7-6.4% (39-46mmol/mol). Insulin resistance (HOMA-IR) and beta-cell function (HOMA-%B) indices were assessed by homeostasis model assessment. Incident diabetes was defined as FPG ≥ 7.0mmol/l, HbA1c ≥ 6.5% (48mmol/mol), or initiation of antidiabetic medications. Among the 7,208 participants with prediabetes, 4,410 (61.2%) remained as prediabetes (control group), 2,123 (29.5%) reverted to normal glucose regulation (regressors), and 675 (9.4%) progressed to type 2 diabetes (progressors) after 5 years. Compared with the control group, the progressors had higher baseline HOMA-IR (2.48 ± 1.45 versus 2.06 ± 1.20, P prediabetes, longitudinal change in insulin resistance was the predominant factor in Koreans. Copyright © 2018 Southern Society for Clinical Investigation. Published by Elsevier Inc. All rights reserved.

  1. Immune and Metabolic Regulation Mechanism of Dangguiliuhuang Decoction against Insulin Resistance and Hepatic Steatosis

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    Hui Cao

    2017-07-01

    Full Text Available Dangguiliuhuang decoction (DGLHD is a traditional Chinese medicine (TCM formula, which mainly consists of angelica, radix rehmanniae, radix rehmanniae praeparata, scutellaria baicalensis, coptis chinensis, astragalus membranaceus, and golden cypress, and used for the treatment of diabetes and some autoimmune diseases. In this study, we explored the potential mechanism of DGLHD against insulin resistance and fatty liver in vivo and in vitro. Our data revealed that DGLHD normalized glucose and insulin level, increased the expression of adiponectin, diminished fat accumulation and lipogenesis, and promoted glucose uptake. Metabolomic analysis also demonstrated that DGLHD decreased isoleucine, adenosine, and cholesterol, increased glutamine levels in liver and visceral adipose tissue (VAT of ob/ob mice. Importantly, DGLHD promoted the shift of pro-inflammatory to anti-inflammatory cytokines, suppressed T lymphocytes proliferation, and enhanced regulatory T cells (Tregs differentiation. DGLHD also inhibited dendritic cells (DCs maturation, attenuated DCs-stimulated T cells proliferation and secretion of IL-12p70 cytokine from DCs, and promoted the interaction of DCs with Tregs. Further studies indicated that the changed PI3K/Akt signaling pathway and elevated PPAR-γ expression were not only observed with the ameliorated glucose and lipid metabolism in adipocytes and hepatocytes, but also exhibited in DCs and T cells by DGLHD. Collectively, our results suggest that DGLHD exerts anti-insulin resistant and antisteatotic effects by improving abnormal immune and metabolic homeostasis. And DGLHD may be a novel approach to the treatment of obesity-related insulin resistance and hepatic steatosis.

  2. Cardiac Development and Transcription Factors: Insulin Signalling, Insulin Resistance, and Intrauterine Nutritional Programming of Cardiovascular Disease

    Science.gov (United States)

    Govindsamy, Annelene; Naidoo, Strinivasen

    2018-01-01

    Programming with an insult or stimulus during critical developmental life stages shapes metabolic disease through divergent mechanisms. Cardiovascular disease increasingly contributes to global morbidity and mortality, and the heart as an insulin-sensitive organ may become insulin resistant, which manifests as micro- and/or macrovascular complications due to diabetic complications. Cardiogenesis is a sequential process during which the heart develops into a mature organ and is regulated by several cardiac-specific transcription factors. Disrupted cardiac insulin signalling contributes to cardiac insulin resistance. Intrauterine under- or overnutrition alters offspring cardiac structure and function, notably cardiac hypertrophy, systolic and diastolic dysfunction, and hypertension that precede the onset of cardiovascular disease. Optimal intrauterine nutrition and oxygen saturation are required for normal cardiac development in offspring and the maintenance of their cardiovascular physiology. PMID:29484207

  3. Fasting insulin has a stronger association with an adverse cardiometabolic risk profile than insulin resistance: the RISC study

    DEFF Research Database (Denmark)

    de Rooij, Susanne R; Dekker, Jacqueline M; Kozakova, Michaela

    2009-01-01

    OBJECTIVE: Fasting insulin concentrations are often used as a surrogate measure of insulin resistance. We investigated the relative contributions of fasting insulin and insulin resistance to cardiometabolic risk and preclinical atherosclerosis. DESIGN AND METHODS: The Relationship between Insulin...... of the metabolic syndrome in 1177 participants. Carotid artery intima media thickness (IMT) was measured by ultrasound to assess preclinical atherosclerosis. RESULTS: Fasting insulin was correlated with all elements of the metabolic syndrome. Insulin sensitivity (M/I) was correlated with most elements. The odds...... ratio for the metabolic syndrome of those in the highest quartile of fasting insulin compared with those in the lower quartiles was 5.4 (95% confidence interval (CI) 2.8-10.3, adjusted for insulin sensitivity) in men and 5.1 (2.6-9.9) in women. The odds ratio for metabolic syndrome of those with insulin...

  4. Peripheral insulin resistance and impaired insulin signaling contribute to abnormal glucose metabolism in preterm baboons.

    Science.gov (United States)

    Blanco, Cynthia L; McGill-Vargas, Lisa L; Gastaldelli, Amalia; Seidner, Steven R; McCurnin, Donald C; Leland, Michelle M; Anzueto, Diana G; Johnson, Marney C; Liang, Hanyu; DeFronzo, Ralph A; Musi, Nicolas

    2015-03-01

    Premature infants develop hyperglycemia shortly after birth, increasing their morbidity and death. Surviving infants have increased incidence of diabetes as young adults. Our understanding of the biological basis for the insulin resistance of prematurity and developmental regulation of glucose production remains fragmentary. The objective of this study was to examine maturational differences in insulin sensitivity and the insulin-signaling pathway in skeletal muscle and adipose tissue of 30 neonatal baboons using the euglycemic hyperinsulinemic clamp. Preterm baboons (67% gestation) had reduced peripheral insulin sensitivity shortly after birth (M value 12.5 ± 1.5 vs 21.8 ± 4.4 mg/kg · min in term baboons) and at 2 weeks of age (M value 12.8 ± 2.6 vs 16.3 ± 4.2, respectively). Insulin increased Akt phosphorylation, but these responses were significantly lower in preterm baboons during the first week of life (3.2-fold vs 9.8-fold). Preterm baboons had lower glucose transporter-1 protein content throughout the first 2 weeks of life (8%-12% of term). In preterm baboons, serum free fatty acids (FFAs) did not decrease in response to insulin, whereas FFAs decreased by greater than 80% in term baboons; the impaired suppression of FFAs in the preterm animals was paired with a decreased glucose transporter-4 protein content in adipose tissue. In conclusion, peripheral insulin resistance and impaired non-insulin-dependent glucose uptake play an important role in hyperglycemia of prematurity. Impaired insulin signaling (reduced Akt) contributes to the defect in insulin-stimulated glucose disposal. Counterregulatory hormones are not major contributors.

  5. Neuronal calcium sensor synaptotagmin-9 is not involved in the regulation of glucose homeostasis or insulin secretion.

    Directory of Open Access Journals (Sweden)

    Natalia Gustavsson

    Full Text Available BACKGROUND: Insulin secretion is a complex and highly regulated process. It is well established that cytoplasmic calcium is a key regulator of insulin secretion, but how elevated intracellular calcium triggers insulin granule exocytosis remains unclear, and we have only begun to define the identities of proteins that are responsible for sensing calcium changes and for transmitting the calcium signal to release machineries. Synaptotagmins are primarily expressed in brain and endocrine cells and exhibit diverse calcium binding properties. Synaptotagmin-1, -2 and -9 are calcium sensors for fast neurotransmitter release in respective brain regions, while synaptotagmin-7 is a positive regulator of calcium-dependent insulin release. Unlike the three neuronal calcium sensors, whose deletion abolished fast neurotransmitter release, synaptotagmin-7 deletion resulted in only partial loss of calcium-dependent insulin secretion, thus suggesting that other calcium-sensors must participate in the regulation of insulin secretion. Of the other synaptotagmin isoforms that are present in pancreatic islets, the neuronal calcium sensor synaptotagmin-9 is expressed at the highest level after synaptotagmin-7. METHODOLOGY/PRINCIPAL FINDINGS: In this study we tested whether synaptotagmin-9 participates in the regulation of glucose-stimulated insulin release by using pancreas-specific synaptotagmin-9 knockout (p-S9X mice. Deletion of synaptotagmin-9 in the pancreas resulted in no changes in glucose homeostasis or body weight. Glucose tolerance, and insulin secretion in vivo and from isolated islets were not affected in the p-S9X mice. Single-cell capacitance measurements showed no difference in insulin granule exocytosis between p-S9X and control mice. CONCLUSIONS: Thus, synaptotagmin-9, although a major calcium sensor in the brain, is not involved in the regulation of glucose-stimulated insulin release from pancreatic β-cells.

  6. Neuronal calcium sensor synaptotagmin-9 is not involved in the regulation of glucose homeostasis or insulin secretion.

    Science.gov (United States)

    Gustavsson, Natalia; Wang, Xiaorui; Wang, Yue; Seah, Tingting; Xu, Jun; Radda, George K; Südhof, Thomas C; Han, Weiping

    2010-11-09

    Insulin secretion is a complex and highly regulated process. It is well established that cytoplasmic calcium is a key regulator of insulin secretion, but how elevated intracellular calcium triggers insulin granule exocytosis remains unclear, and we have only begun to define the identities of proteins that are responsible for sensing calcium changes and for transmitting the calcium signal to release machineries. Synaptotagmins are primarily expressed in brain and endocrine cells and exhibit diverse calcium binding properties. Synaptotagmin-1, -2 and -9 are calcium sensors for fast neurotransmitter release in respective brain regions, while synaptotagmin-7 is a positive regulator of calcium-dependent insulin release. Unlike the three neuronal calcium sensors, whose deletion abolished fast neurotransmitter release, synaptotagmin-7 deletion resulted in only partial loss of calcium-dependent insulin secretion, thus suggesting that other calcium-sensors must participate in the regulation of insulin secretion. Of the other synaptotagmin isoforms that are present in pancreatic islets, the neuronal calcium sensor synaptotagmin-9 is expressed at the highest level after synaptotagmin-7. In this study we tested whether synaptotagmin-9 participates in the regulation of glucose-stimulated insulin release by using pancreas-specific synaptotagmin-9 knockout (p-S9X) mice. Deletion of synaptotagmin-9 in the pancreas resulted in no changes in glucose homeostasis or body weight. Glucose tolerance, and insulin secretion in vivo and from isolated islets were not affected in the p-S9X mice. Single-cell capacitance measurements showed no difference in insulin granule exocytosis between p-S9X and control mice. Thus, synaptotagmin-9, although a major calcium sensor in the brain, is not involved in the regulation of glucose-stimulated insulin release from pancreatic β-cells.

  7. Intramuscular Lipid Metabolism in the Insulin Resistance of Smoking

    OpenAIRE

    Bergman, Bryan C.; Perreault, Leigh; Hunerdosse, Devon M.; Koehler, Mary C.; Samek, Ali M.; Eckel, Robert H.

    2009-01-01

    OBJECTIVE Smoking decreases insulin action and increases the risk of type 2 diabetes in humans. Mechanisms responsible for smoking-induced insulin resistance are unclear. We hypothesized smokers would have increased intramuscular triglyceride (IMTG) and diacylglycerol (DAG) concentration and decreased fractional synthesis rate (FSR) compared with nonsmokers. RESEARCH DESIGN AND METHODS Nonsmokers (n = 18, aged 20 ± 0.5 years, BMI 22 ± 0.4 kg/m2, body fat 20 ± 2%, 0 cigarettes per day) and smo...

  8. Dual role of proapoptotic BAD in insulin secretion and beta cell survival.

    Science.gov (United States)

    Danial, Nika N; Walensky, Loren D; Zhang, Chen-Yu; Choi, Cheol Soo; Fisher, Jill K; Molina, Anthony J A; Datta, Sandeep Robert; Pitter, Kenneth L; Bird, Gregory H; Wikstrom, Jakob D; Deeney, Jude T; Robertson, Kirsten; Morash, Joel; Kulkarni, Ameya; Neschen, Susanne; Kim, Sheene; Greenberg, Michael E; Corkey, Barbara E; Shirihai, Orian S; Shulman, Gerald I; Lowell, Bradford B; Korsmeyer, Stanley J

    2008-02-01

    The proapoptotic BCL-2 family member BAD resides in a glucokinase-containing complex that regulates glucose-driven mitochondrial respiration. Here, we present genetic evidence of a physiologic role for BAD in glucose-stimulated insulin secretion by beta cells. This novel function of BAD is specifically dependent upon the phosphorylation of its BH3 sequence, previously defined as an essential death domain. We highlight the pharmacologic relevance of phosphorylated BAD BH3 by using cell-permeable, hydrocarbon-stapled BAD BH3 helices that target glucokinase, restore glucose-driven mitochondrial respiration and correct the insulin secretory response in Bad-deficient islets. Our studies uncover an alternative target and function for the BAD BH3 domain and emphasize the therapeutic potential of phosphorylated BAD BH3 mimetics in selectively restoring beta cell function. Furthermore, we show that BAD regulates the physiologic adaptation of beta cell mass during high-fat feeding. Our findings provide genetic proof of the bifunctional activities of BAD in both beta cell survival and insulin secretion.

  9. OXIDATIVE STRESS: ITS ROLE IN INSULIN SECRETION, HORMONE RECEPTION BY ADIPOCYTES AND LIPOLYSIS IN ADIPOSE TISSUE

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    V. V. Ivanov

    2014-01-01

    Full Text Available Oxidative stress is one of the pathogenetic components of many diseases during which generation of reactive oxigen species increases and the capacity of the antioxidant protection system diminishes. In the research of the last decades special attention has been given to adipose tissue, production of adipokines by it and their role in development of immunoresistance associated with formation of the metabolic syndrome and diabetes.Search for methods of therapeutic correction of adipokine secretion disorders, their influence on metabolism of separate cells and the organism on the whole as well as development of new approaches to correction of disorders in cell sensitivity to insulin are extremely topical nowadays. Systematization and consolidation of accumulated data allow to determine the strategies of further research more accurately; as a result, we have attempted to summarize and analyze the accumulated data on the role of adipose tissue in oxidative stress development.On the basis of literature data and the results of the personal investigations, the role of adipose tissue in forming oxidative stress in diabetes has been analyzed in the article. Brief description of adipose tissue was given as a secretory organ regulating metabolic processes in adipocytes and influencing functions of various organs and systems of the body. Mechanisms of disorder in insulin secretion as well as development of insulin sesistance in type I diabetes were described along with the contribution of lipolysis in adipose tissue to these processes.

  10. Integrative analysis of a cross-loci regulation network identifies App as a gene regulating insulin secretion from pancreatic islets.

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    Zhidong Tu

    Full Text Available Complex diseases result from molecular changes induced by multiple genetic factors and the environment. To derive a systems view of how genetic loci interact in the context of tissue-specific molecular networks, we constructed an F2 intercross comprised of >500 mice from diabetes-resistant (B6 and diabetes-susceptible (BTBR mouse strains made genetically obese by the Leptin(ob/ob mutation (Lep(ob. High-density genotypes, diabetes-related clinical traits, and whole-transcriptome expression profiling in five tissues (white adipose, liver, pancreatic islets, hypothalamus, and gastrocnemius muscle were determined for all mice. We performed an integrative analysis to investigate the inter-relationship among genetic factors, expression traits, and plasma insulin, a hallmark diabetes trait. Among five tissues under study, there are extensive protein-protein interactions between genes responding to different loci in adipose and pancreatic islets that potentially jointly participated in the regulation of plasma insulin. We developed a novel ranking scheme based on cross-loci protein-protein network topology and gene expression to assess each gene's potential to regulate plasma insulin. Unique candidate genes were identified in adipose tissue and islets. In islets, the Alzheimer's gene App was identified as a top candidate regulator. Islets from 17-week-old, but not 10-week-old, App knockout mice showed increased insulin secretion in response to glucose or a membrane-permeant cAMP analog, in agreement with the predictions of the network model. Our result provides a novel hypothesis on the mechanism for the connection between two aging-related diseases: Alzheimer's disease and type 2 diabetes.

  11. Mechanisms linking brain insulin resistance to Alzheimer's disease

    Science.gov (United States)

    Matioli, Maria Niures P.S.; Nitrini, Ricardo

    2015-01-01

    Several studies have indicated that Diabetes Mellitus (DM) can increase the risk of developing Alzheimer's disease (AD). This review briefly describes current concepts in mechanisms linking DM and insulin resistance/deficiency to AD. Insulin/insulin-like growth factor (IGF) resistance can contribute to neurodegeneration by several mechanisms which involve: energy and metabolism deficits, impairment of Glucose transporter-4 function, oxidative and endoplasmic reticulum stress, mitochondrial dysfunction, accumulation of AGEs, ROS and RNS with increased production of neuro-inflammation and activation of pro-apoptosis cascade. Impairment in insulin receptor function and increased expression and activation of insulin-degrading enzyme (IDE) have also been described. These processes compromise neuronal and glial function, with a reduction in neurotransmitter homeostasis. Insulin/IGF resistance causes the accumulation of AβPP-Aβ oligomeric fibrils or insoluble larger aggregated fibrils in the form of plaques that are neurotoxic. Additionally, there is production and accumulation of hyper-phosphorylated insoluble fibrillar tau which can exacerbate cytoskeletal collapse and synaptic disconnection. PMID:29213950

  12. Assesment of propolis supplementation on insulin resistance in diabetic patients

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    nazli samadi

    2017-05-01

    Full Text Available Introduction: Diabetes mellitus is a common endocrine disease . The number of people with diabetes over the last twenty years has doubled . Asia as a result of rapid economic growth , as the center of the epidemic in the world . Iran is among the countries with a high prevalence of diabetes mellitus . Use of medicinal plants as adjunctive therapy along with medication always been original . In recent years the tendency of patients to alternative therapies and traditional medicine has increased. Methods : Among patients referred to clinics of University of Medical Sciences, Yazd, Iran , 67 people were selected and randomly divided into two groups,intervention or placebo. Patients in the intervention group received 3 tablets of 300 mg bee propolis and in the control group received placebo . The study lasted 12 weeks . Serum insulin and insulin resistance index were evaluated at the beginning and end of the study. Results: 57 patients completed the study . The average demographic characteristics , anthropometric indices , serum insulin and insulin resistance index at the beginning and end of the study between the two groups showed no significant difference. Conclusion : In this study , supplementation with bee propolis for 12 weeks , on the serum insulin and indices of insulin resistance in patients with type II diabetes is not effective . Further studies are needed to make a final decision.

  13. Mechanisms linking brain insulin resistance to Alzheimer's disease

    Directory of Open Access Journals (Sweden)

    Maria Niures P.S. Matioli

    Full Text Available Several studies have indicated that Diabetes Mellitus (DM can increase the risk of developing Alzheimer's disease (AD. This review briefly describes current concepts in mechanisms linking DM and insulin resistance/deficiency to AD. Insulin/insulin-like growth factor (IGF resistance can contribute to neurodegeneration by several mechanisms which involve: energy and metabolism deficits, impairment of Glucose transporter-4 function, oxidative and endoplasmic reticulum stress, mitochondrial dysfunction, accumulation of AGEs, ROS and RNS with increased production of neuro-inflammation and activation of pro-apoptosis cascade. Impairment in insulin receptor function and increased expression and activation of insulin-degrading enzyme (IDE have also been described. These processes compromise neuronal and glial function, with a reduction in neurotransmitter homeostasis. Insulin/IGF resistance causes the accumulation of AβPP-Aβ oligomeric fibrils or insoluble larger aggregated fibrils in the form of plaques that are neurotoxic. Additionally, there is production and accumulation of hyper-phosphorylated insoluble fibrillar tau which can exacerbate cytoskeletal collapse and synaptic disconnection.

  14. Insulin resistance in uremia: Insulin receptor kinase activity in liver and muscle from chronic uremic rats

    International Nuclear Information System (INIS)

    Cecchin, F.; Ittoop, O.; Sinha, M.K.; Caro, J.F.

    1988-01-01

    The authors have studied the structure and function of the partially purified insulin receptors from liver and skeletal muscle in a rat model of severe chronic uremia. 125 I-insulin binding was higher in the liver from uremic rats when compared with ad libitum- and pair-fed controls. Furthermore, the ability of insulin to stimulate the autophosphorylation of the β-subunit and insulin receptor kinase activity using Glu 80 , Tyr 20 as exogenous phosphoacceptor was increased in the liver of the uremic animals. The structural characteristics of the receptors, as determined by electrophoretic mobilities of affinity labeled α-subunit and the phosphorylated β-subunit, were normal in uremia. 125 I-insulin binding and insulin receptor kinase activity were similar in the skeletal muscle from uremic and pair- and ad libitum-fed animals. Thus the data are supportive of the hypothesis that in liver and muscle of chronic uremic rats, insulin resistance is due to a defect(s) distal to the insulin receptor kinase

  15. Resveratrol ameliorates the chemical and microbial induction of inflammation and insulin resistance in human placenta, adipose tissue and skeletal muscle.

    Science.gov (United States)

    Tran, Ha T; Liong, Stella; Lim, Ratana; Barker, Gillian; Lappas, Martha

    2017-01-01

    Gestational diabetes mellitus (GDM), which complicates up to 20% of all pregnancies, is associated with low-grade maternal inflammation and peripheral insulin resistance. Sterile inflammation and infection are key mediators of this inflammation and peripheral insulin resistance. Resveratrol, a stilbene-type phytophenol, has been implicated to exert beneficial properties including potent anti-inflammatory and antidiabetic effects in non-pregnant humans and experimental animal models of GDM. However, studies showing the effects of resveratrol on inflammation and insulin resistance associated with GDM in human tissues have been limited. In this study, human placenta, adipose (omental and subcutaneous) tissue and skeletal muscle were stimulated with pro-inflammatory cytokines TNF-α and IL-1β, the bacterial product lipopolysaccharide (LPS) and the synthetic viral dsRNA analogue polyinosinic:polycytidylic acid (poly(I:C)) to induce a GDM-like model. Treatment with resveratrol significantly reduced the expression and secretion of pro-inflammatory cytokines IL-6, IL-1α, IL-1β and pro-inflammatory chemokines IL-8 and MCP-1 in human placenta and omental and subcutaneous adipose tissue. Resveratrol also significantly restored the defects in the insulin signalling pathway and glucose uptake induced by TNF-α, LPS and poly(I:C). Collectively, these findings suggest that resveratrol reduces inflammation and insulin resistance induced by chemical and microbial products. Resveratrol may be a useful preventative therapeutic for pregnancies complicated by inflammation and insulin resistance, like GDM.

  16. Activation of AMPK improves inflammation and insulin resistance in adipose tissue and skeletal muscle from pregnant women.

    Science.gov (United States)

    Liong, Stella; Lappas, Martha

    2015-12-01

    Gestational diabetes mellitus (GDM) is characterised by maternal peripheral insulin resistance and inflammation. Sterile inflammation and bacterial infection are key mediators of this enhanced inflammatory response. Adenosine monophosphate (AMP)-activated kinase (AMPK), which is decreased in insulin resistant states, possesses potent pro-inflammatory actions. There are, however, no studies on the role of AMPK in pregnancies complicated by GDM. Thus, the aims of this study were (i) to compare the expression of AMPK in adipose tissue and skeletal muscle from women with GDM and normal glucose-tolerant (NGT) pregnant women; and (ii) to investigate the effect of AMPK activation on inflammation and insulin resistance induced by the bacterial endotoxin lipopolysaccharide (LPS) and the pro-inflammatory cytokine IL-1β. When compared to NGT pregnant women, AMPKα activity was significantly lower in women with GDM as evidenced by a decrease in threonine phosphorylation of AMPKα. Activation of AMPK, using two pharmacologically distinct compounds, AICAR or phenformin, significantly suppressed LPS- or IL-1β-induced gene expression and secretion of pro-inflammatory cytokine IL-6, the chemokines IL-8 and MCP-1, and COX-2 and subsequent prostaglandin release from adipose tissue and skeletal muscle. In addition, activators of AMPK decreased skeletal muscle insulin resistance induced by LPS or IL-1β as evidenced by increased insulin-stimulated phosphorylation of IRS-1, GLUT-4 expression and glucose uptake. These findings suggest that AMPK may play an important role in inflammation and insulin resistance.

  17. Insulin resistance and glucose levels in subjects with subclinical hypothyroidism

    International Nuclear Information System (INIS)

    Kahn, S.H.; Fazal, N.; Yasir, M.; Asif, N.; Rafi, T.

    2017-01-01

    To compare insulin resistance and glycemic indicators among subjects with euthyroidism and subclinical hypothyroidism. Study Design: Comparative cross-sectional study. Place and Duration of Study: Department of Pathology and Medicine, PNS Hafeez, Islamabad, in collaboration with the Department of Chemical Pathology and Endocrinology at the Armed Forces Institute of Pathology (AFIP), Rawalpindi, from December 2015 to September 2016. Methodology: Subjects referred for executive screening of apparently healthy population (without any known history of diabetes, hypertension, heart disease or other chronic ailments), were included. Subjects were grouped as euthyroidism and subclinical hypothyroidism. Results: Median (IQR) insulin resistance indices including fasting insulin and Homeostasis Model Assessment for Insulin Resistance in subjects with group-1 (n=176, 87%, Thyroid Stimulating Hormone: 0.5 - 3.5 mIU/L) and group-2 (n=26, 13%, Thyroid Stimulating Hormone: 3.51 - 15 mIU/L) were 7.6 (6.70) vs. 11.4 (13.72, p=0.040) and 1.77 (1.79) vs. 2.8 (3.07, p=0.071). The median differences for fasting plasma glucose were 5.0 (1.0) in group-1 vs. 5.0 (1.47) for Group-2 [p=0.618], and glycated hemoglobin was 5.60 (1.1) vs. 5.60 (1.7, p=0.824). Homeostasis Model Assessment for beta sensitivity index in paradox showed slightly higher values for group-2 [median (IQR) 86.67 (92.94)] than group-1 [111.6 (189.64, p= 0.040)]. Conclusion: Measures of insulin resistance including Homeostasis Model Assessment for Insulin Resistance and fasting insulin levels were significantly different between subjects with euthyroidism and having subclinical hypothyroidism. (author)

  18. Huntingtin-interacting protein 14 is a type 1 diabetes candidate protein regulating insulin secretion and β-cell apoptosis

    DEFF Research Database (Denmark)

    Berchtold, Lukas Adrian; Størling, Zenia Marian; Ortis, Fernanda

    2011-01-01

    Type 1 diabetes (T1D) is a complex disease characterized by the loss of insulin-secreting β-cells. Although the disease has a strong genetic component, and several loci are known to increase T1D susceptibility risk, only few causal genes have currently been identified. To identify disease...... genes in T1D, including the INS gene. An unexpected top-scoring candidate gene was huntingtin-interacting protein (HIP)-14/ZDHHC17. Immunohistochemical analysis of pancreatic sections demonstrated that HIP14 is almost exclusively expressed in insulin-positive cells in islets of Langerhans. RNAi...... knockdown experiments established that HIP14 is an antiapoptotic protein required for β-cell survival and glucose-stimulated insulin secretion. Proinflammatory cytokines (IL-1β and IFN-γ) that mediate β-cell dysfunction in T1D down-regulated HIP14 expression in insulin-secreting INS-1 cells and in isolated...

  19. Major Pathophysiology in Prediabetes and Type 2 Diabetes: Decreased Insulin in Lean and Insulin Resistance in Obese.

    Science.gov (United States)

    Kabadi, Udaya M

    2017-06-01

    Lowering of body mass index (BMI) to ≥25 kg/m 2 as obesity by ADA suggests insulin resistance as a major mechanism of impaired glucose metabolism (IGM) in Asians. However, glimepiride, an insulin secretagogue, delayed onset of type 2 diabetes (DM2) from prediabetes (PreDM), indicating decreased insulin secretion (IS) as a major factor in lean (L; BMI DM2. Seventy-five men and 45 women ages 36 to 75 years were divided into six groups: LN, LPreDM, LDM2, ObN, ObPreDM, and ObDM2. Determination of IS by insulinogenic indices (I/G) at fasting (FI/FG), first phase (∆I/∆G), and cumulative responses over 2 hours of OGTT (CRI/CRG), and IR by FIXFG, ∆IX∆G, and CRIXCRG. Changes in IS and IR for PreDM and DM2 were calculated as % fall and % rise, respectively, from levels in N. All indices of IS and IR were lower ( P DM2 ( P < 0.05) in both groups. However, the declines in IS were greater ( P < 0.05) than rises in IR in LPreDM and LDM2. Whereas, the rises in IR were higher ( P < 0.05) than declines in IS in ObPreDM and ObDM2. In L, major mechanism of IGM is declining IS and not rising IR documented among Ob.

  20. Acanthosis nigricans: a flag for insulin resistance

    African Journals Online (AJOL)

    2013-11-04

    Nov 4, 2013 ... Outcome measures: OGTT, fasting serum insulin and HOMA IR were the outcome measures studied. Results: This cross-sectional study revealed that 94 subjects with acanthosis nigricans (31.34%) had IR. Grades III and IV, and textures II and III, were more predictive of IR. Acanthosis nigricans grading was ...

  1. Visceral adiposity, insulin resistance and cancer risk

    LENUS (Irish Health Repository)

    Donohoe, Claire L

    2011-06-22

    Abstract Background There is a well established link between obesity and cancer. Emerging research is characterising this relationship further and delineating the specific role of excess visceral adiposity, as opposed to simple obesity, in promoting tumorigenesis. This review summarises the evidence from an epidemiological and pathophysiological perspective. Methods Relevant medical literature was identified from searches of PubMed and references cited in appropriate articles identified. Selection of articles was based on peer review, journal and relevance. Results Numerous epidemiological studies consistently identify increased risk of developing carcinoma in the obese. Adipose tissue, particularly viscerally located fat, is metabolically active and exerts systemic endocrine effects. Putative pathophysiological mechanisms linking obesity and carcinogenesis include the paracrine effects of adipose tissue and systemic alterations associated with obesity. Systemic changes in the obese state include chronic inflammation and alterations in adipokines and sex steroids. Insulin and the insulin-like growth factor axis influence tumorigenesis and also have a complex relationship with adiposity. There is evidence to suggest that insulin and the IGF axis play an important role in mediating obesity associated malignancy. Conclusions There is much evidence to support a role for obesity in cancer progression, however further research is warranted to determine the specific effect of excess visceral adipose tissue on tumorigenesis. Investigation of the potential mechanisms underpinning the association, including the role of insulin and the IGF axis, will improve understanding of the obesity and cancer link and may uncover targets for intervention.

  2. Acute pain induces insulin resistance in humans

    DEFF Research Database (Denmark)

    Greisen, J.; Juhl, C.B.; Grøfte, Thorbjørn

    2001-01-01

    Background: Painful trauma results in a disturbed metabolic state with impaired insulin sensitivity, which is related to the magnitude of the trauma. The authors explored whether pain per se influences hepatic and extrahepatic actions of insulin. Methods: Ten healthy male volunteers underwent two...... randomly sequenced hyperinsulinemic–euglycemic (insulin infusion rate, 0.6 mU · kg-1 · min-1 for 180 min) clamp studies 4 weeks apart. Self-controlled painful electrical stimulation was applied to the abdominal skin for 30 min, to a pain intensity of 8 on a visual analog scale of 0–10, just before...... the clamp procedure (study P). In the other study, no pain was inflicted (study C). Results: Pain reduced whole-body insulin-stimulated glucose uptake from 6.37 ± 1.87 mg · kg-1 · min-1 (mean ± SD) in study C to 4.97 ± 1.38 mg · kg-1 · min-1 in study P (P

  3. Impaired Glucose Metabolism Despite Decreased Insulin Resistance After Renal Transplantation

    Directory of Open Access Journals (Sweden)

    Manfred Hecking

    2012-06-01

    Full Text Available The pathophysiology underlying new-onset diabetes after transplantation (NODAT is unresolved. We obtained demographics and laboratory data from all 1064 renal transplant recipients followed at our outpatient clinic in 2009/2010, randomly assigned 307 patients without previously diagnosed diabetes to a routine 2-hour oral glucose tolerance test (OGTT, and compared the metabolic results to a large, unrelated cross-sectional cohort of non-transplanted subjects. Among renal transplant recipients, 11% had a history of NODAT, and 12% had type 1 and type 2 diabetes. 42% of all OGTTs were abnormal (9% diabetic, predominantly in older patients who received tacrolimus. Compared to non-transplanted subjects, basal glucose was lower and HbA1c higher in renal transplant patients. Compared to non-transplanted subjects, insulin secretion was inferior, and insulin sensitivity improved at ≥6 months, as well as 3 months post-transplantation:(The Figure shows linear spline interpolation; all p for overall difference between non-Tx and Tx patients <0.02, using likelihood ratio testing. Our results indicate that impaired insulin secretion is the predominant problem after renal transplantation, suggesting benefit for therapeutic regimens that preserve beta cell function after renal transplantation. The mechanism of increased insulin sensitivity might be pathophysiologically similar to pancreatogenic diabetes.fx1

  4. Validation of insulin resistance indexes in a stable renal transplant population

    NARCIS (Netherlands)

    Oterdoom, Leendert H.; de Vries, Aiko P. J.; van Son, Willem J.; Homan van der Heide, Jaap J.; Ploeg, Rutger J.; Gansevoort, Ron T.; de Jong, Paul E.; Gans, Rijk O. B.; Bakker, Stephan J. L.

    2005-01-01

    The purpose of this study was to investigate the validity of established insulin resistance indexes, based on fasting blood parameters, in a stable renal transplant population. Fasting insulin, homeostasis model assessment (HOMA), the quantitative insulin sensitivity check index (QUICKI), and

  5. Validation of insulin resistance indexes in a stable renal transplant population

    NARCIS (Netherlands)

    Oterdoom, LH; De Vries, APJ; Van Son, WJ; Van Der Heide, JJH; Ploeg, RJ; Gansevoort, RT; De Jong, PE; Gans, ROB; Bakker, SJL

    2005-01-01

    OBJECTIVE - The purpose of this study was to investigate the validity of established insulin resistance indexes, based on fasting blood parameters, in a stable renal transplant population. RESEARCH DESIGN AND METHODS - Fasting insulin, homeostasis model assessment (HOMA), the quantitative insulin

  6. Lipid metabolism disturbances contribute to insulin resistance and decrease insulin sensitivity by malathion exposure in Wistar rat.

    Science.gov (United States)

    Lasram, Mohamed Montassar; Bouzid, Kahena; Douib, Ines Bini; Annabi, Alya; El Elj, Naziha; El Fazaa, Saloua; Abdelmoula, Jaouida; Gharbi, Najoua

    2015-04-01

    Several studies showed that organophosphorus pesticides disturb glucose homeostasis and can increase incidence of metabolic disorders and diabetes via insulin resistance. The current study investigates the influence of malathion on glucose metabolism regulation, in vivo, during subchronic exposure. Malathion was administered orally (200 mg/kg), once a day for 28 consecutive days. Plasma glucose, insulin and Glycated hemoglobin levels were significantly increased while hepatic glycogen content was decreased in intoxicated animals compared with the control group. Furthermore, there was a significant disturbance of lipid content in subchronic treated and post-treated rats deprived of malathion for one month. In addition, we used the homeostasis model assessment (HOMA) to assess insulin resistance (HOMA-IR) and pancreatic β-cell function (HOMA-β). Our results show that malathion increases insulin resistance biomarkers and decreases insulin sensitivity indices. Statistical analysis demonstrates that there was a positive and strong significant correlation between insulin level and insulin resistance indices, HOMA-IR, HOMA-β. Similarly, a negative and significant correlation was also found between insulin level and insulin sensitivity indices. For the first time, we demonstrate that malathion induces insulin resistance in vivo using homeostasis model assessment and these changes were detectable one month after the end of exposure. To explain insulin resistance induced by malathion we focus on lipid metabolism disturbances and their interaction with many proteins involved in insulin signaling pathways.

  7. Glycated albumin suppresses glucose-induced insulin secretion by impairing glucose metabolism in rat pancreatic β-cells

    Directory of Open Access Journals (Sweden)

    Muto Takashi

    2011-04-01

    Full Text Available Abstract Background Glycated albumin (GA is an Amadori product used as a marker of hyperglycemia. In this study, we investigated the effect of GA on insulin secretion from pancreatic β cells. Methods Islets were collected from male Wistar rats by collagenase digestion. Insulin secretion in the presence of non-glycated human albumin (HA and GA was measured under three different glucose concentrations, 3 mM (G3, 7 mM (G7, and 15 mM (G15, with various stimulators. Insulin secretion was measured with antagonists of inducible nitric oxide synthetase (iNOS, and the expression of iNOS-mRNA was investigated by real-time PCR. Results Insulin secretion in the presence of HA and GA was 20.9 ± 3.9 and 21.6 ± 5.5 μU/3 islets/h for G3 (P = 0.920, and 154 ± 9.3 and 126.1 ± 7.3 μU/3 islets/h (P = 0.046, for G15, respectively. High extracellular potassium and 10 mM tolbutamide abrogated the inhibition of insulin secretion by GA. Glyceraldehyde, dihydroxyacetone, methylpyruvate, GLP-1, and forskolin, an activator of adenylate cyclase, did not abrogate the inhibition. Real-time PCR showed that GA did not induce iNOS-mRNA expression. Furthermore, an inhibitor of nitric oxide synthetase, aminoguanidine, and NG-nitro-L-arginine methyl ester did not abrogate the inhibition of insulin secretion. Conclusion GA suppresses glucose-induced insulin secretion from rat pancreatic β-cells through impairment of intracellular glucose metabolism.

  8. Higher Fetal Insulin Resistance in Chinese Pregnant Women with Gestational Diabetes Mellitus and Correlation with Maternal Insulin Resistance

    OpenAIRE

    Wang, Qiuwei; Huang, Ruiping; Yu, Bin; Cao, Fang; Wang, Huiyan; Zhang, Ming; Wang, Xinhong; Zhang, Bin; Zhou, Hong; Zhu, Ziqiang

    2013-01-01

    OBJECTIVE: The aim of this study was to determine the effect of gestational diabetes mellitus (GDM) on fetal insulin resistance or β-cell function in Chinese pregnant women with GDM. MEASUREMENTS: Maternal fasting blood and venous cord blood samples (reflecting fetal condition) were collected in 65 well-controlled Chinese GDM mothers (only given dietary intervention) and 83 control subjects. The insulin, glucose and proinsulin concentrations of both maternal and cord blood samples were measur...

  9. GLP-1 Restores Altered Insulin and Glucagon Secretion in Posttransplantation Diabetes

    DEFF Research Database (Denmark)

    Halden, Thea A S; Egeland, Erlend J; Åsberg, Anders

    2016-01-01

    OBJECTIVE: Development of posttransplantation diabetes (PTDM) is characterized by reduced insulin secretion and sensitivity. We aimed to investigate whether hyperglucagonemia could play a role in PTDM and to examine the insulinotropic and glucagonostatic effects of the incretin hormone glucagon...... h of infusion, a 2-h hyperglycemic clamp (fasting plasma glucose + 5 mmol/L) was established. Five grams of arginine was given as an intravenous bolus 10 min before termination of the clamp. RESULTS: Fasting concentrations of glucagon (P = 0.92) and insulin (P = 0.23) were similar between the groups...... to arginine (P = 0.01) but similar glucagon and proinsulin responses compared with control subjects. In the preclamp phase, GLP-1 lowered fasting plasma glucose to the same extent in both groups but reduced glucagon only in PTDM patients. During hyperglycemic clamp, GLP-1 reduced glucagon concentrations...

  10. Cephalic phase secretion of insulin and other enteropancreatic hormones in humans

    DEFF Research Database (Denmark)

    Veedfald, Simon; Plamboeck, Astrid; Deacon, Carolyn F

    2016-01-01

    Enteropancreatic hormone secretion is thought to include a cephalic phase, but the evidence in humans is ambiguous. We studied vagally induced gut hormone responses with and without muscarinic blockade in 10 glucose-clamped healthy men (age: 24.5 ± 0.6 yr, means ± SE; body mass index: 24.0 ± 0.5 kg...... and abolished the MSF response. Neither insulin, C-peptide, glucose-dependent insulinotropic polypeptide (GIP), nor glucagon-like peptide-1 (GLP-1) levels changed in response to MSF or atropine. Glucagon and ghrelin levels were markedly attenuated by atropine prior to and during the clamp: at t = 105 min...... and 3.7 ± 21 pg/ml (means ± SE), P phase response was absent for insulin, glucagon, GLP-1, GIP, and ghrelin....

  11. Significance of glucagon for insulin secretion and hepatic glycogenolysis during exercise in rats

    DEFF Research Database (Denmark)

    Richter, Erik; Galbo, H; Holst, J J

    1981-01-01

    The significance of glucagon and of the sympatho-adrenal system for insulin secretion and hepatic glycogen depletion during exercise was studied. Male rats were either adrenodemedullated and chemically sympathectomized with 6-hydroxydopamine (SX) or sham-treated (C). During light ether anesthesia......, cardiac blood for glucose analysis and a biopsy of the liver were obtained, and either antigen-stripped glucagon antibodies (A) or control gamma globulins (N) in saline were injected through the cardiac cannula. Subsequently, the rats swam in tepid water (33-34 degree C) for 100 minutes with a tail weight...... attached (2% of body weight). Then cardiac blood was drawn for analysis of glucose, insulin and glucagon, and a sample of the liver was collected. In both CA and CN rats, the blood glucose concentration tended to increase (p less than 0.1) during exercise, whereas hepatic glycogen depletion and the plasma...

  12. RFX6 Regulates Insulin Secretion by Modulating Ca2+ Homeostasis in Human β Cells

    Directory of Open Access Journals (Sweden)

    Vikash Chandra

    2014-12-01

    Full Text Available Development and function of pancreatic β cells involve the regulated activity of specific transcription factors. RFX6 is a transcription factor essential for mouse β cell differentiation that is mutated in monogenic forms of neonatal diabetes. However, the expression and functional roles of RFX6 in human β cells, especially in pathophysiological conditions, are poorly explored. We demonstrate the presence of RFX6 in adult human pancreatic endocrine cells. Using the recently developed human β cell line EndoC-βH2, we show that RFX6 regulates insulin gene transcription, insulin content, and secretion. Knockdown of RFX6 causes downregulation of Ca2+-channel genes resulting in the reduction in L-type Ca2+-channel activity that leads to suppression of depolarization-evoked insulin exocytosis. We also describe a previously unreported homozygous missense RFX6 mutation (p.V506G that is associated with neonatal diabetes, which lacks the capacity to activate the insulin promoter and to increase Ca2+-channel expression. Our data therefore provide insights for understanding certain forms of neonatal diabetes.

  13. Zinc Status Affects Glucose Homeostasis and Insulin Secretion in Patients with Thalassemia

    Directory of Open Access Journals (Sweden)

    Ellen B. Fung

    2015-06-01

    Full Text Available Up to 20% of adult patients with Thalassemia major (Thal live with diabetes, while 30% may be zinc deficient. The objective of this study was to explore the relationship between zinc status, impaired glucose tolerance and insulin sensitivity in Thal patients. Charts from thirty subjects (16 male, 27.8 ± 9.1 years with Thal were reviewed. Patients with low serum zinc had significantly lower fasting insulin, insulinogenic and oral disposition indexes (all p < 0.05 and elevated glucose response curve, following a standard 75 g oral load of glucose compared to those with normal serum zinc after controlling for baseline (group × time interaction p = 0.048. Longitudinal data in five patients with a decline in serum zinc over a two year follow up period (−19.0 ± 9.6 μg/dL, showed consistent increases in fasting glucose (3.6 ± 3.2 mg/dL and insulin to glucose ratios at 120 min post glucose dose (p = 0.05. Taken together, these data suggest that the frequently present zinc deficiency in Thal patients is associated with decreased insulin secretion and reduced glucose disposal. Future zinc trials will require modeling of oral glucose tolerance test data and not simply measurement of static indices in order to understand the complexities of pancreatic function in the Thal patient.

  14. Serum visfatin in relation to insulin resistance and markers of hyperandrogenism in lean and obese women with polycystic ovary syndrome.

    Science.gov (United States)

    Kowalska, Irina; Straczkowski, Marek; Nikolajuk, Agnieszka; Adamska, Agnieszka; Karczewska-Kupczewska, Monika; Otziomek, Elzbieta; Wolczynski, Slawomir; Gorska, Maria

    2007-07-01

    Visfatin, a protein secreted by adipose tissue, is suggested to play a role in pathogenesis of insulin resistance. In polycystic ovary syndrome (PCOS), insulin resistance might be involved in the development of endocrine and metabolic abnormalities. The aim of the study was to asses the relation between serum visfatin concentration and insulin sensitivity and markers of hyperandrogenism in lean and obese PCOS patients. The study group consisted of 70 women with PCOS (23 lean and 47 obese) and 45 healthy women (25 lean and 20 obese). Euglycemic hyperinsulinemic clamp and the measurements of serum visfatin, sex hormones were performed. The PCOS group had lower insulin sensitivity (P=0.00049) and higher serum visfatin (P=0.047) in comparison to the control group. The decrease in insulin sensitivity was present in both the lean (P=0.019) and obese (P=0.0077) PCOS subjects, whereas increase in serum visfatin was observed only in lean PCOS subjects (P=0.012). In the whole group, serum visfatin was negatively correlated with insulin sensitivity (r=-0.27, P=0.004). This relationship was also observed in the subgroup of lean (r=-0.30, P=0.038), but not obese women. Additionally, in lean women, visfatin was associated with serum testosterone (r=0.47, P=0.002) and free androgen index (r=0.48, P=0.002), independently of other potential confounding factors. Visfatin is associated with insulin resistance and markers of hyperandrogenism in lean PCOS patients.

  15. Subcellular localization, mobility, and kinetic activity of glucokinase in glucose-responsive insulin-secreting cells.

    Science.gov (United States)

    Stubbs, M; Aiston, S; Agius, L

    2000-12-01

    We investigated the subcellular localization, mobility, and activity of glucokinase in MIN6 cells, a glucose-responsive insulin-secreting beta-cell line. Glucokinase is present in the cytoplasm and a vesicular/granule compartment that is partially colocalized with insulin granules. The granular staining of glucokinase is preserved after permeabilization of the cells with digitonin. There was no evidence for changes in distribution of glucokinase between the cytoplasm and the granule compartment during incubation of the cells with glucose. The rate of release of glucokinase and of phosphoglucoisomerase from digitonin-permeabilized cells was slower when cells were incubated at an elevated glucose concentration (S0.5 approximately 15 mmol/l). This effect of glucose was counteracted by competitive inhibitors of glucokinase (5-thioglucose and mannoheptulose) but was unaffected by fructose analogs and may be due to changes in cell shape or conformation of the cytoskeleton that are secondary to glucose metabolism. Based on the similar release of glucokinase and phosphoglucoisomerase, we found no evidence for specific binding of cytoplasmic digitonin-extractable glucokinase. The affinity of beta-cells for glucose is slightly lower than that in cell extracts and, unlike that in hepatocytes, is unaffected by fructose, tagatose, or a high-K+ medium, which is consistent with the lack of change in glucokinase distribution or release. We conclude that glucokinase is present in two locations, cytoplasm and the granular compartment, and that it does not translocate between them. This conclusion is consistent with the lack of adaptive changes in the glucose phosphorylation affinity. The glucokinase activity associated with the insulin granules may have a role in either direct or indirect coupling between glucose phosphorylation and insulin secretion.

  16. Association of type 2 diabetes candidate polymorphisms in KCNQ1 with incretin and insulin secretion

    DEFF Research Database (Denmark)

    Müssig, Karsten; Staiger, Harald; Machicao, Fausto

    2009-01-01

    OBJECTIVE: KCNQ1 gene polymorphisms are associated with type 2 diabetes. This linkage appears to be mediated by altered beta-cell function. In an attempt to study underlying mechanisms, we examined the effect of four KCNQ1 single nucleotide polymorphisms (SNPs) on insulin secretion upon different...... stimuli. RESEARCH DESIGN AND METHODS: We genotyped 1,578 nondiabetic subjects at increased risk of type 2 diabetes for rs151290, rs2237892, rs2237895, and rs2237897. All participants underwent an oral glucose tolerance test (OGTT); glucagon-like peptide (GLP)-1 and gastric inhibitory peptide secretion...... was measured in 170 participants. In 519 participants, a hyperinsulinemic-euglycemic clamp was performed, in 314 participants an intravenous glucose tolerance test (IVGTT), and in 102 subjects a hyperglycemic clamp combined with GLP-1 and arginine stimuli. RESULTS: rs151290 was nominally associated with 30-min...

  17. Influence of insulin sensitivity and secretion on glycated albumin and hemoglobin A1c in pregnant women with gestational diabetes mellitus.

    Science.gov (United States)

    Pan, Jiemin; Zhang, Feng; Zhang, Lei; Bao, Yuqian; Tao, Minfang; Jia, Weiping

    2013-06-01

    To examine the differential effects of insulin sensitivity and secretion on hemoglobin A1c (HbA1c) and glycated albumin (GA) at 24-32weeks of pregnancy in women with gestational diabetes mellitus (GDM). A cross-sectional, sequential case series study was performed in pregnant women with an abnormal 50-g oral glucose-screening test. Hemoglobin A1c and GA measurements were taken during oral glucose tolerance test (OGTT). The homeostasis model assessment of insulin resistance (HOMA-IR) and beta-cell function (HOMA-%β), insulin sensitivity index (ISOGTT), and modified insulinogenic index were calculated to assess insulin sensitivity and secretory function. A total of 713 pregnant women were enrolled. The GDM group had lower ISOGTT and insulinogenic index scores, and a higher HOMA-IR score. Hemoglobin A1c was positively correlated with HOMA-IR. Glycated albumin was negatively correlated with insulinogenic index and HOMA-%β. Multiple regression analysis revealed that HbA1c was independently associated with diastolic pressure, 0- and 120-minute glucose, and HOMA-IR; GA was independently associated with 0- and 120-minute glucose. Compared with HbA1c, GA is more closely correlated with fasting and postprandial glucose, regardless of insulin resistance and blood pressure, and might be a better monitoring index in women with GDM. Copyright © 2013 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

  18. Insulin elevates leptin secretion and mRNA levels via cyclic AMP in 3T3-L1 adipocytes deprived of glucose

    Directory of Open Access Journals (Sweden)

    Tomomi Tsubai

    2016-11-01

    Conclusion: Insulin alone stimulates leptin secretion and elevates leptin mRNA levels via cAMP under the lack of glucose metabolism, while glucose is a significant and ambivalent effector on the insulin effects of leptin.

  19. How does brain insulin resistance develop in Alzheimer's disease?

    Science.gov (United States)

    De Felice, Fernanda G; Lourenco, Mychael V; Ferreira, Sergio T

    2014-02-01

    Compelling preclinical and clinical evidence supports a pathophysiological connection between Alzheimer's disease (AD) and diabetes. Altered metabolism, inflammation, and insulin resistance are key pathological features of both diseases. For many years, it was generally considered that the brain was insensitive to insulin, but it is now accepted that this hormone has central neuromodulatory functions, including roles in learning and memory, that are impaired in AD. However, until recently, the molecular mechanisms accounting for brain insulin resistance in AD have remained elusive. Here, we review recent evidence that sheds light on how brain insulin dysfunction is initiated at a molecular level and why abnormal insulin signaling culminates in synaptic failure and memory decline. We also discuss the cellular basis underlying the beneficial effects of stimulation of brain insulin signaling on cognition. Discoveries summarized here provide pathophysiological background for identification of novel molecular targets and for development of alternative therapeutic approaches in AD. Copyright © 2014 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

  20. Effects of GCK, GCKR, G6PC2 and MTNR1B variants on glucose metabolism and insulin secretion.

    Directory of Open Access Journals (Sweden)

    Cheng Hu

    Full Text Available BACKGROUND: Single nucleotide polymorphisms (SNPs from GCK, GCKR, G6PC2 and MTNR1B were found to modulate the fasting glucose levels. The current study aimed to replicate this association in the Chinese population and further analyze their effects on biphasic insulin secretion. METHODS/PRINCIPAL FINDINGS: SNPs from GCK, GCKR, G6PC2 and MTNR1B were genotyped in the Shanghai Chinese, including 3,410 type 2 diabetes patients and 3,412 controls. The controls were extensively phenotyped for the traits related to glucose metabolism and insulin secretion. We replicated the association between GCK rs1799884, G6PC2 rs16856187 and MTNR1B rs10830963 and fasting glucose in our samples (p = 0.0003-2.0x10(-8. GCK rs1799884 and G6PC2 rs16856187 showed association to HOMA-beta, insulinogenic index and both first- and second-phases insulin secretion (p = 0.0030-0.0396. MTNR1B rs10830963 was associated to HOMA-beta, insulinogenic index and first-phase insulin secretion (p = 0.0102-0.0426, but not second-phase insulin secretion (p = 0.9933. Combined effect analyses showed individuals carrying more risk allele for high fasting glucose tended to have a higher glucose levels at both fasting and 2 h during OGTTs (p = 1.7x10(-13 and 0.0009, respectively, as well as lower HOMA-beta, insulinogenic index and both first- and second-phases insulin secretion (p = 0.0321-1.1x10(-7. CONCLUSIONS/SIGNIFICANCE: We showed that SNPs from GCK, G6PC2 and MTNR1B modulated the fasting glucose levels in the normoglycaemic population while SNPs from G6PC2 and GCKR was associated with type 2 diabetes. Moreover, we found GCK and G6PC2 genetic variants were associated to both first- and second-phases insulin secretion while MTNR1B genetic variant was associated with first-phase insulin secretion, but not second-phase insulin secretion.

  1. Insulin resistance, insulin response, and obesity as indicators of metabolic risk

    DEFF Research Database (Denmark)

    Ferrannini, Ele; Balkau, Beverley; Coppack, Simon W

    2007-01-01

    CONTEXT: Insulin resistance (IR) and obesity, especially abdominal obesity, are regarded as central pathophysiological features of a cluster of cardiovascular risk factors (CVRFs), but their relative roles remain undefined. Moreover, the differential impact of IR viz. insulin response has not been...... evaluated. OBJECTIVE: The objective of this study was to dissect out the impact of obesity, abdominal obesity, and IR/insulin response on CVRF. DESIGN: This was a cross-sectional study. SETTING: The study was conducted at 21 research centers in Europe. SUBJECTS: The study included a cohort of 1308......-cholesterol, and lower high-density lipoprotein-cholesterol, and insulin response to higher heart rate, blood pressure and fasting glucose, and the same dyslipidemic profile as IR (P

  2. Diabetes mellitus, a complex and heterogeneous disease, and the role of insulin resistance as a determinant of diabetic kidney disease.

    Science.gov (United States)

    Karalliedde, Janaka; Gnudi, Luigi

    2016-02-01

    Diabetes mellitus (DM) is increasingly recognized as a heterogeneous condition. The individualization of care and treatment necessitates an understanding of the individual patient's pathophysiology of DM that underpins their DM classification and clinical presentation. Classical type-2 diabetes mellitus is due to a combination of insulin resistance and an insulin secretory defect. Type-1 diabetes is characterized by a near-absolute deficiency of insulin secretion. More recently, advances in genetics and a better appreciation of the atypical features of DM has resulted in more categories of diabetes. In the context of kidney disease, patients with DM and microalbuminuria are more insulin resistant, and insulin resistance may be a pathway that results in accelerated progression of diabetic kidney disease. This review summarizes the updated classification of DM, including more rarer categories and their associated renal manifestations that need to be considered in patients who present with atypical features. The benefits and limitations of the tests utilized to make a diagnosis of DM are discussed. We also review the putative pathways and mechanisms by which insulin resistance drives the progression of diabetic kidney disease. © The Author 2014. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

  3. Analysis of the effect of diabetes type 2 duration on beta cell secretory function and insulin resistance

    Directory of Open Access Journals (Sweden)

    Popović Ljiljana

    2006-01-01

    Full Text Available Diabetes type 2 is a chronic metabolic disorder. Pathogenesis of diabetes type 2 results from the impaired insulin secretion, impaired insulin action and increased endogenous glucose production. Diabetes evolves through several phases characterized by qualitative and quantitative changes of beta cell secretory function. The aim of our study was to analyze the impact of diabetes duration on beta cell secretory function and insulin resistance. The results indicated significant negative correlation of diabetes duration and fasting insulinemia, as well as beta cell secretory function assessed by HOMA β index. Our study also found significant negative correlation of diabetes duration and insulin resistance assessed by HOMA IR index. Significant positive correlation was established between beta cell secretory capacity (fasting insulinemia and HOMA β and insulin resistance assessed by HOMA IR index, independently of diabetes duration. These results indicate that: beta cell secretory capacity, assessed by HOMA β index, significantly decreases with diabetes duration. In parallel with decrease of fasting insulinemia, reduction of insulin resistance assessed by HOMA IR index was found as well.

  4. Studies of insulin resistance in congenital generalized lipodystrophy

    DEFF Research Database (Denmark)

    Søvik, O; Vestergaard, H; Trygstad, O

    1996-01-01

    suppressed lipid oxidation in the controls. It is concluded that patients with congenital generalized lipodystrophy may present severe insulin resistance with regard to hepatic glucose production as well as muscle glycogen synthesis and lipid oxidation. The results suggest a postreceptor defect in the action......, immunoreactive protein and mRNA levels. The patients had fasting hyperinsulinaemia, and the rate of total glucose disposal was severely impaired, primarily due to a decreased non-oxidative glucose metabolism. In the patient studied with muscle biopsy, the expected activation of glycogen synthase by insulin did...... not occur. In both patients there was severely increased hepatic glucose output in the basal state, suggesting a failure of insulin to suppress hepatic gluconeogenesis. During insulin infusion a substantially elevated rate of lipid oxidation remained in the patients, in contrast to the almost completely...

  5. Meal composition affects insulin secretion in women with type 2 diabetes: a comparison with healthy controls. The Hoorn prandial study.

    Science.gov (United States)

    Alssema, M; Schindhelm, R K; Rijkelijkhuizen, J M; Kostense, P J; Teerlink, T; Nijpels, G; Heine, R J; Dekker, J M

    2009-03-01

    Early insulin secretion following a meal is representative for normal physiology and may depend on meal composition. To compare the effects of a fat-rich and a carbohydrate-rich mixed meal on insulinogenic index as a measure of early insulin secretion in normoglycemic women (NGM) and in women with type 2 diabetes mellitus (DM2), and to assess the relationship of anthropometric and metabolic factors with insulinogenic index. Postmenopausal women, 76 with NGM and 64 with DM2, received a fat-rich meal and a carbohydrate-rich meal on separate occasions. Early insulin response was estimated as insulinogenic index ( big up tri, Deltainsulin(0-30 min)/ big up tri, Deltaglucose(0-30 min)) for each meal. Associations of fasting and postprandial triglycerides, body mass index, waist and hip circumference and alanine aminotransferase with insulinogenic indices were determined. Women with NGM present with higher insulinogenic index than women with DM2. The insulinogenic index following the fat-rich meal ( big up tri, DeltaI(30)/ big up tri, DeltaG(30) (fat)) was higher than the index following the carbohydrate-rich meal (big up tri, DeltaI(30)/ big up tri, DeltaG(30) (CH)) (Pwomen with DM2, and not significant in women with NGM). In women with DM2, homeostasis model assessment for insulin resistance was positively associated with big up tri, DeltaI(30)/ big up tri, DeltaG(30) (CH). In women with NGM, waist circumference was independently and inversely associated with big up tri, DeltaI(30)/ big up tri, DeltaG(30) (fat) and with big up tri, DeltaI(30)/ big up tri, DeltaG(30) (CH); hip circumference was positively associated with big up tri, DeltaI(30)/ big up tri, DeltaG(30) (fat). The insulinogenic index following the fat-rich meal was higher than following the isocaloric carbohydrate-rich meal, which might favorably affect postprandial glucose excursions, especially in women with DM2. The association between a larger waist circumference and a lower meal-induced insulinogenic

  6. Investigation of pancreas indocrine function in order to reveal subclinical insulin resistence in women with acne

    OpenAIRE

    Filippova, T.; Rudykh, N.; Shevchuk, A.

    2008-01-01

    Changed glycemic curves and indices of insulin resistance, the increase of insulin basal level in comparison with healthy persons, presence of antibodies to insulin antigen, decrease of level sex hormone bilding globulin were revealed in patients with acne. It can be considered as sign of formation of subclinical insulin resistance.

  7. Dietary patterns and the insulin resistance phenotype among non-diabetic adults

    Science.gov (United States)

    Background: Information on the relation between dietary patterns derived by cluster analysis and insulin resistance is scarce. Objective: To compare insulin resistance phenotypes, including waist circumference, body mass index, fasting and 2-hour post-challenge insulin, insulin sensitivity index (I...

  8. Total body fat, pro-inflammatory cytokines and insulin resistance in Indian subjects

    Energy Technology Data Exchange (ETDEWEB)

    Yajnik, C S [Diabetes Unit, KEM Hospital Research Centre, Pune (India); Yudkin, J S [Whittington Hospital, University College of London, London (United Kingdom); Shetty, P S [London School of Hygiene and Tropical Medicine, London (United Kingdom); Kurpad, A [St. John' s Medical College, Bangalore (India)

    1999-07-01

    There is a growing epidemic of insulin resistance syndrome (IRS) in Indians. We postulate that increased susceptibility of the urban Indians to insulin resistance is a result of a tendency to increased fat deposition from the time of intrauterine life (thrifty phenotype), exaggerated in the urban environment by a positive energy balance. The pro-inflammatory cytokines secreted by the inflammatory cells as well by the adipose tissue could aggravate insulin resistance and endothelial damage and therefore, increase the susceptibility to type 2 diabetes and coronary heart disease (CHD) independent of the previously proposed glucose fatty acid cycle mechanism. In a preliminary study, we propose to make detailed measurements of the proposed mechanisms in a selected population from 3 geographical locations in and near the city of Pune, India and also validate simple 'epidemiologic' measurements of body composition with 'reference' measurements. One hundred men (30 to 50y) each from the three geographical locations (rural, urban slum-dwellers and urban middle class in Pune) will be studied for: (i) Body composition: Anthropometric and bioimpedance measurement of total body fat (to be calibrated against deuterated water in 30 subjects from each location), and muscle mass by anthropometry and urinary creatinine excretion; (ii) Body fat distribution by subscapular- triceps ratio, waist-hip ratio; (iii) Metabolic: Glucose tolerance and insulin resistance variables (insulin, lipids, NEFA) and leptin; (iv) Endothelial markers: e-Selectin and von Willebrand Factor (vWF); (v) Inflammatory markers and pro-inflammatory cytokines: C-reactive protein (CRP), Interleukin-6 (IL-6) and tumour necrosis factor (TNF- {alpha}); (vi) Energy Balance: Assessment of nutritional intake (calories, carbohydrates, proteins and fats, n3 and n6 fatty acids) and physical activity by a questionnaire. Insulin resistance variables, endothelial markers, cytokines and obesity parameters will be compared in

  9. Total body fat, pro-inflammatory cytokines and insulin resistance in Indian subjects

    International Nuclear Information System (INIS)

    Yajnik, C.S.; Yudkin, J.S.; Shetty, P.S.; Kurpad, A.

    1999-01-01

    There is a growing epidemic of insulin resistance syndrome (IRS) in Indians. We postulate that increased susceptibility of the urban Indians to insulin resistance is a result of a tendency to increased fat deposition from the time of intrauterine life (thrifty phenotype), exaggerated in the urban environment by a positive energy balance. The pro-inflammatory cytokines secreted by the inflammatory cells as well by the adipose tissue could aggravate insulin resistance and endothelial damage and therefore, increase the susceptibility to type 2 diabetes and coronary heart disease (CHD) independent of the previously proposed glucose fatty acid cycle mechanism. In a preliminary study, we propose to make detailed measurements of the proposed mechanisms in a selected population from 3 geographical locations in and near the city of Pune, India and also validate simple 'epidemiologic' measurements of body composition with 'reference' measurements. One hundred men (30 to 50y) each from the three geographical locations (rural, urban slum-dwellers and urban middle class in Pune) will be studied for: (i) Body composition: Anthropometric and bioimpedance measurement of total body fat (to be calibrated against deuterated water in 30 subjects from each location), and muscle mass by anthropometry and urinary creatinine excretion; (ii) Body fat distribution by subscapular- triceps ratio, waist-hip ratio; (iii) Metabolic: Glucose tolerance and insulin resistance variables (insulin, lipids, NEFA) and leptin; (iv) Endothelial markers: e-Selectin and von Willebrand Factor (vWF); (v) Inflammatory markers and pro-inflammatory cytokines: C-reactive protein (CRP), Interleukin-6 (IL-6) and tumour necrosis factor (TNF- α); (vi) Energy Balance: Assessment of nutritional intake (calories, carbohydrates, proteins and fats, n3 and n6 fatty acids) and physical activity by a questionnaire. Insulin resistance variables, endothelial markers, cytokines and obesity parameters will be compared in the 3

  10. Relationship of serum resistin with insulin resistance and obesity

    International Nuclear Information System (INIS)

    Zaidi, S.I.Z.

    2015-01-01

    Background: Adipokines have been implicated in the modulation of insulin sensitivity and glucose tolerance and have thus gained importance in the study of Type 2 diabetes mellitus (T2DM). Resistin, a unique signalling molecule, is being proposed as a significant factor in the pathogenesis of obesity-related insulin resistance. However, its relevance to human diabetes mellitus remains uncertain and controversial. This study was therefore planned to compare and correlate the potential role of resistin in obese patients with T2DM and obese non-diabetic controls and also to evaluate the correlation between resistin and marker of obesity and glycaemic parameters. Method: Fasting serum resistin, glucose and insulin were measured in forty obese diabetics (mean±SD BMI 35±5 kg/m2) and forty obese non-diabetics (mean±SD BMI 33±3 kg/m2). Insulin resistance was assessed using the HOMA-IR formula derived from fasting insulin and glucose levels. Results: Serum resistin levels (38±8 ng/ml) were significantly higher in type 2 diabetic patients as compared with the controls. Fasting blood glucose (164±46 mg/dl), serum insulin (37±7 μU/ml) and insulin resistance (19±8), were considerably higher among the studied diabetics than in the controls. Pearson's correlation analysis revealed positive correlation between serum resistin and BMI (p=0.001) and HOMA-IR (p=0.561) in diabetic subjects. Similarly, a correlation also existed between serum resistin and BMI (p=0.016) and HOMA-IR (p=0.307) in control obese subjects. However, it was highly significant in diabetics as compared to non-diabetic controls. Conclusion: A significant BMI-dependent association exists between resistin and insulin resistance in patients with T2DM. It appears that resistin may play a role in the pathogenesis of obesity and insulin resistance and that both of these may contribute to the development of T2DM. (author)

  11. Role of PTEN in TNFα induced insulin resistance

    International Nuclear Information System (INIS)

    Bulger, David A.; Conley, Jermaine; Conner, Spencer H.; Majumdar, Gipsy; Solomon, Solomon S.

    2015-01-01

    Aims/hypothesis: PTEN may play a reversible role in TNFα induced insulin resistance, which has been linked to obesity-associated insulin resistance (IR). Methods: Western blots for PTEN and p-Akt were performed on H-411E liver cells incubated with insulin, TNFα, and in selected experiments VO-OHpic vanadium complex in the presence and absence of PTEN siRNA. Total PTEN was compared to β-actin loading control and p-Akt was compared to total Akt. Results: Western blot and Real Time RT-PCR experiments showed increased PTEN after TNFα treatment (p = 0.04); slightly decreased PTEN after insulin treatment; and slightly increased PTEN after insulin + TNFα treatment. PTEN siRNA markedly inhibited the TNFα-induced increase in PTEN (p < 0.01) without significantly changing the p-Akt levels. The vanadium complex, exhibiting insulin-like effects, also significantly prevented the TNFα-induced increase in PTEN. Combining insulin and VO-OHpic was additive, providing both proof of concept and insight into mechanism. Discussion: The PTEN increase due to TNFα treatment was reversible by both PTEN siRNA knockdown and VO-OHpic treatment. Thus, PTEN is identified as a potential new therapeutic target for reducing IR in Type 2 DM. - Highlights: • TNFα treatment induced a significant increase in PTEN in H-411E liver cells. • PTEN siRNA knockdown prevented this effect. • VO-OHpic (vanadium complex) treatment, like insulin, decreased PTEN protein levels. • Thus, PTEN is identified as a potential therapeutic target in DM Type 2

  12. Role of PTEN in TNFα induced insulin resistance

    Energy Technology Data Exchange (ETDEWEB)

    Bulger, David A. [Departments of Medicine and Pharmacology, University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Medicine and Research Services, Veterans Association Medical Center, Memphis, TN 38104 (United States); Wellcome Trust Medical Research Council Institute of Metabolic Science, Cambridge CB2 0QQ (United Kingdom); National Institute of Diabetes & Digestive & Kidney Disease, National Institutes of Health, Bethesda, MD 20892 (United States); Conley, Jermaine [Medicine and Research Services, Veterans Association Medical Center, Memphis, TN 38104 (United States); Conner, Spencer H.; Majumdar, Gipsy [Departments of Medicine and Pharmacology, University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Medicine and Research Services, Veterans Association Medical Center, Memphis, TN 38104 (United States); Solomon, Solomon S., E-mail: ssolomon@uthsc.edu [Departments of Medicine and Pharmacology, University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Medicine and Research Services, Veterans Association Medical Center, Memphis, TN 38104 (United States)

    2015-06-05

    Aims/hypothesis: PTEN may play a reversible role in TNFα induced insulin resistance, which has been linked to obesity-associated insulin resistance (IR). Methods: Western blots for PTEN and p-Akt were performed on H-411E liver cells incubated with insulin, TNFα, and in selected experiments VO-OHpic vanadium complex in the presence and absence of PTEN siRNA. Total PTEN was compared to β-actin loading control and p-Akt was compared to total Akt. Results: Western blot and Real Time RT-PCR experiments showed increased PTEN after TNFα treatment (p = 0.04); slightly decreased PTEN after insulin treatment; and slightly increased PTEN after insulin + TNFα treatment. PTEN siRNA markedly inhibited the TNFα-induced increase in PTEN (p < 0.01) without significantly changing the p-Akt levels. The vanadium complex, exhibiting insulin-like effects, also significantly prevented the TNFα-induced increase in PTEN. Combining insulin and VO-OHpic was additive, providing both proof of concept and insight into mechanism. Discussion: The PTEN increase due to TNFα treatment was reversible by both PTEN siRNA knockdown and VO-OHpic treatment. Thus, PTEN is identified as a potential new therapeutic target for reducing IR in Type 2 DM. - Highlights: • TNFα treatment induced a significant increase in PTEN in H-411E liver cells. • PTEN siRNA knockdown prevented this effect. • VO-OHpic (vanadium complex) treatment, like insulin, decreased PTEN protein levels. • Thus, PTEN is identified as a potential therapeutic target in DM Type 2.

  13. Linking mitochondrial bioenergetics to insulin resistance via redox biology

    Science.gov (United States)

    Fisher-Wellman, Kelsey H.; Neufer, P. Darrell

    2012-01-01

    Chronic overnutrition and physical inactivity are major risk factors for insulin resistance and type 2 diabetes. Recent research indicates that overnutrition generates an increase in hydrogen peroxide (H2O2) emission from mitochondria, serving as a release valve to relieve the reducing pressure created by fuel overload, as well as a primary signal to ultimately decrease insulin sensitivity. H2O2 is a major input to cellular redox circuits that link to cysteine residues throughout the entire proteome to regulate cell function. Here we review the principles of mitochondrial bioenergetics and redox systems biology and offer new insight as to how H2O2 emission may be linked via redox biology to the etiology of insulin resistance. PMID:22305519

  14. Effects of experimentally induced mild hyperthyroidism on growth hormone and insulin secretion and sex steroid levels in healthy young men.

    Science.gov (United States)

    Lovejoy, J C; Smith, S R; Bray, G A; Veldhuis, J D; Rood, J C; Tulley, R

    1997-12-01

    Although triiodothyronine (T3) exerts major regulatory actions in both animals and humans, most clinical studies of T3 administration have been relatively short-term. The present study examined the effects of more than 2 months (63 days) of low-dose T3 treatment on overnight pulsatile growth hormone (GH) secretion, short-term insulin secretion, and of sex steroid levels in seven healthy, lean men studied at an inpatient metabolic unit. At baseline, there were strong correlations between sex hormone-binding globulin (SHBG) and several measures of GH production, including total GH production (r = .99), GH interburst interval (r = -.75), and GH mass (r = .82). SHBG was also inversely correlated with basal insulin secretion (r = -.74). There was a 42% increase in serum levels of total testosterone (18.5 +/- 1.3 to 26.3 +/- 1.8 nmol/L, P = .005) and a 150% increase in SHBG (18.0 +/- 2.2 to 44.9 +/- 7.0 nmol/L, P = .008) following T3 treatment. Estradiol and free testosterone levels were unchanged by treatment, although free testosterone decreased from 142.8 +/- 18.4 to 137.3 +/- 19.5 pmol/L. T3 treatment significantly reduced the GH interburst interval (P secretion. There were no statistically significant effects of T3 treatment on insulin secretion, although insulin peak amplitude, mass secreted per burst, and total production all decreased. We conclude that experimentally induced T3 excess in healthy men produces significant and sustained changes in sex hormone levels and GH secretion. Furthermore, there are strong associations between SHBG and both GH and insulin secretion independent of thyroid hormone excess that require additional study.

  15. Tumour necrosis factor-alpha infusion produced insulin resistance but no change in the incretin effect in healthy volunteers.

    Science.gov (United States)

    Nielsen, Signe Tellerup; Lehrskov-Schmidt, Louise; Krogh-Madsen, Rikke; Solomon, Thomas P J; Lehrskov-Schmidt, Lars; Holst, Jens Juul; Møller, Kirsten

    2013-11-01

    Type 2 diabetes mellitus (T2DM) is associated with peripheral insulin resistance, impaired incretin effect, and increased plasma levels of tumour necrosis factor-alpha (TNF-α). Although TNF-α infusion at a dose that induces systemic inflammation in healthy volunteers has been demonstrated to induce peripheral insulin resistance, the influence of this cytokine on the incretin effect is unknown. We investigated whether systemic inflammation induced by TNF-α infusion in healthy volunteers alters the incretin hormone response to oral and intravenous glucose loads in a crossover study design with ten healthy male volunteers (mean age 24 years, mean body mass index 23.7 kg/m(2) ). The study consisted of four study days: days 1 and 2, 6-h infusion of saline; days 3 and 4, 6-h infusion of TNF-α; days 1 and 3, 4-h oral glucose tolerance test; and days 2 and 4, 4-h corresponding intravenous isoglycaemic glucose tolerance test. Glucose tolerance tests were initiated after 2 h of saline/TNF-α infusion. Plasma concentrations of TNF-α, interleukin 6, glucose, incretin hormones, and cortisol, and serum concentrations of C-peptide and insulin were measured throughout the study days. Insulin sensitivity was estimated by the Matsuda index and homeostasis model assessment of insulin resistance (HOMA-IR). Prehepatic insulin secretion rates were calculated. TNF-α infusion induced symptoms of systemic inflammation; increased plasma levels of cortisol, TNF-α, and interleukin 6; and increased the HOMA-IR. The secretion of incretin hormones as well as the incretin effect remained unchanged. In healthy young male volunteers, acute systemic inflammation induced by infusion of TNF-α is associated with insulin resistance with no change in the incretin effect. Copyright © 2013 John Wiley & Sons, Ltd.

  16. Early enhancements of hepatic and later of peripheral insulin sensitivity combined with increased postprandial insulin secretion contribute to improved glycemic control after Roux-en-Y gastric bypass

    DEFF Research Database (Denmark)

    Bojsen-Møller, Kirstine N; Dirksen, Carsten; Jørgensen, Nils Bruun

    2014-01-01

    after RYGB. Participants were included after a preoperative diet induced total weight loss of -9.2±1.2%. Hepatic and peripheral insulin sensitivity were assessed using the hyperinsulinemic euglycemic clamp combined with glucose tracer technique and beta-cell function evaluated in response...... after surgery. Insulin mediated glucose disposal and suppression of fatty acids did not improve immediately after surgery but increased at 3 months and 1 year likely related to the reduction in body weight. Insulin secretion increased after RYGB, but only in patients with type 2 diabetes and only...

  17. Effects of exendin-4 on glucose tolerance, insulin secretion, and beta-cell proliferation depend on treatment dose, treatment duration and meal contents

    International Nuclear Information System (INIS)

    Arakawa, Masayuki; Ebato, Chie; Mita, Tomoya; Hirose, Takahisa; Kawamori, Ryuzo; Fujitani, Yoshio; Watada, Hirotaka

    2009-01-01

    Beta-cell proliferation is regulated by various metabolic demands including peripheral insulin resistance, obesity, and hyperglycemia. In addition to enhancement of glucose-induced insulin secretion, agonists for glucagon-like peptide-1 receptor (GLP-1R) stimulate proliferation and inhibit apoptosis of beta-cells, thereby probably preserve beta-cell mass. To evaluate the beta-cell preserving actions of GLP-1R agonists, we assessed the acute and chronic effects of exendin-4 on beta-cell proliferation, mass and glucose tolerance in C57BL/6J mice under various conditions. Short-term administration of high-dose exendin-4 transiently stimulated beta-cell proliferation. Comparative transcriptomic analysis showed upregulation of IGF-1 receptor and its downstream effectors in islets. Treatment of mice with exendin-4 daily for 4 weeks (long-term administration) and feeding high-fat diet resulted in significant inhibition of weight gain and improvement of glucose tolerance with reduced insulin secretion and beta-cell mass. These findings suggest that long-term GLP-1 treatment results in insulin sensitization of peripheral organs, rather than enhancement of beta-cell proliferation and function, particularly when animals are fed high-fat diet. Thus, the effects of exendin-4 on glucose tolerance, insulin secretion, and beta-cell proliferation largely depend on treatment dose, duration of treatment and meal contents. While GLP-1 enhances proliferation of beta-cells in some diabetic mice models, our results suggest that GLP-1 stimulates beta-cell growth only when expansion of beta-cell mass is required to meet metabolic demands.

  18. Effects of exendin-4 on glucose tolerance, insulin secretion, and beta-cell proliferation depend on treatment dose, treatment duration and meal contents

    Energy Technology Data Exchange (ETDEWEB)

    Arakawa, Masayuki; Ebato, Chie; Mita, Tomoya [Department of Medicine, Metabolism and Endocrinology, Juntendo University School of Medicine, Tokyo (Japan); Hirose, Takahisa [Department of Medicine, Metabolism and Endocrinology, Juntendo University School of Medicine, Tokyo (Japan); Center for Therapeutic Innovations in Diabetes, Juntendo University School of Medicine, Tokyo (Japan); Kawamori, Ryuzo [Department of Medicine, Metabolism and Endocrinology, Juntendo University School of Medicine, Tokyo (Japan); Center for Therapeutic Innovations in Diabetes, Juntendo University School of Medicine, Tokyo (Japan); Center for Beta Cell Biology and Regeneration, Juntendo University School of Medicine, Tokyo (Japan); Sportology Center, Juntendo University School of Medicine, Tokyo (Japan); Fujitani, Yoshio, E-mail: fujitani@juntendo.ac.jp [Department of Medicine, Metabolism and Endocrinology, Juntendo University School of Medicine, Tokyo (Japan); Center for Therapeutic Innovations in Diabetes, Juntendo University School of Medicine, Tokyo (Japan); Watada, Hirotaka, E-mail: hwatada@juntendo.ac.jp [Department of Medicine, Metabolism and Endocrinology, Juntendo University School of Medicine, Tokyo (Japan); Sportology Center, Juntendo University School of Medicine, Tokyo (Japan)

    2009-12-18

    Beta-cell proliferation is regulated by various metabolic demands including peripheral insulin resistance, obesity, and hyperglycemia. In addition to enhancement of glucose-induced insulin secretion, agonists for glucagon-like peptide-1 receptor (GLP-1R) stimulate proliferation and inhibit apoptosis of beta-cells, thereby probably preserve beta-cell mass. To evaluate the beta-cell preserving actions of GLP-1R agonists, we assessed the acute and chronic effects of exendin-4 on beta-cell proliferation, mass and glucose tolerance in C57BL/6J mice under various conditions. Short-term administration of high-dose exendin-4 transiently stimulated beta-cell proliferation. Comparative transcriptomic analysis showed upregulation of IGF-1 receptor and its downstream effectors in islets. Treatment of mice with exendin-4 daily for 4 weeks (long-term administration) and feeding high-fat diet resulted in significant inhibition of weight gain and improvement of glucose tolerance with reduced insulin secretion and beta-cell mass. These findings suggest that long-term GLP-1 treatment results in insulin sensitization of peripheral organs, rather than enhancement of beta-cell proliferation and function, particularly when animals are fed high-fat diet. Thus, the effects of exendin-4 on glucose tolerance, insulin secretion, and beta-cell proliferation largely depend on treatment dose, duration of treatment and meal contents. While GLP-1 enhances proliferation of beta-cells in some diabetic mice models, our results suggest that GLP-1 stimulates beta-cell growth only when expansion of beta-cell mass is required to meet metabolic demands.

  19. Alteration in insulin action

    DEFF Research Database (Denmark)

    Tanti, J F; Gual, P; Grémeaux, T

    2004-01-01

    Insulin resistance, when combined with impaired insulin secretion, contributes to the development of type 2 diabetes. Insulin resistance is characterised by a decrease in insulin effect on glucose transport in muscle and adipose tIssue. Tyrosine phosphorylation of insulin receptor substrate 1 (IRS......-1) and its binding to phosphatidylinositol 3-kinase (PI 3-kinase) are critical events in the insulin signalling cascade leading to insulin-stimulated glucose transport. Modification of IRS-1 by serine phosphorylation could be one of the mechanisms leading to a decrease in IRS-1 tyrosine...... to phosphorylate these serine residues have been identified. These exciting results suggest that serine phosphorylation of IRS-1 is a possible hallmark of insulin resistance in biologically insulin responsive cells or tIssues. Identifying the pathways by which "diabetogenic" factors activate IRS-1 kinases...

  20. Indomethacin treatment prevents high fat diet-induced obesity and insulin resistance but not glucose intolerance in C57BL/6J Mice

    DEFF Research Database (Denmark)

    Fjære, Even; Aune, Ulrike Liisberg; Røen, Kristin

    2014-01-01

    Chronic low grade inflammation is closely linked to obesity-associated insulin resistance. To examine how administration of the anti-inflammatory compound indomethacin, a general cyclooxygenase inhibitor, affected obesity development and insulin sensitivity, we fed obesity-prone male C57BL/6J mice...... a high fat/high sucrose (HF/HS) diet or a regular diet supplemented or not with indomethacin (±INDO) for 7 weeks. Development of obesity, insulin resistance, and glucose intolerance was monitored, and the effect of indomethacin on glucose-stimulated insulin secretion (GSIS) was measured in vivo...... and in vitro using MIN6 β-cells. We found that supplementation with indomethacin prevented HF/HS-induced obesity and diet-induced changes in systemic insulin sensitivity. Thus, HF/HS+INDO-fed mice remained insulin-sensitive. However, mice fed HF/HS+INDO exhibited pronounced glucose intolerance. Hepatic glucose...

  1. Effects of the pesticide amitraz and its metabolite BTS 27271 on insulin and glucagon secretion from the perfused rat pancreas: involvement of alpha2D-adrenergic receptors.

    Science.gov (United States)

    Abu-Basha, E A; Yibchok-Anun, S; Hopper, D L; Hsu, W H

    1999-11-01

    The study purpose was to investigate the direct effect of amitraz, a formamidine insecticide/acaricide, and its active metabolite BTS 27271 on insulin and glucagon secretion from the perfused rat pancreas. Amitraz and BTS 27271 (0.01, 0.1, 1, and 10 micromol/L) inhibited insulin secretion in a concentration-dependent manner. Amitraz increased glucagon secretion at 10 micromol/L, whereas BTS 27271 increased glucagon secretion at 1 and 10 micromol/L. Amitraz- and BTS 27271-induced decreases in insulin secretion and increases in glucagon secretion were not abolished during the 10-minute washout period. During the arginine treatment, both amitraz and BTS 27271 groups (0.1, 1, and 10 micromol/L) had lower insulin secretion and higher glucagon secretion than the control group. Idazoxan, an alpha2A/2D-adrenergic receptor (AR) antagonist, prevented the inhibitory effect of amitraz on insulin secretion in a concentration-dependent manner, but prazosin, an alpha1- and alpha2B/2C-AR antagonist, failed to antagonize the effect of amitraz. These results demonstrate that (1) amitraz and BTS 27271 inhibit insulin and stimulate glucagon secretion from the perfused rat pancreas, (2) amitraz inhibits insulin secretion by activation of alpha2D-ARs, since rats have alpha2D- but not alpha2A-ARs, and (3) amitraz and BTS 27271 may have a high binding affinity to the alpha2D-ARs of pancreatic islets.

  2. High sugar-induced insulin resistance in Drosophila relies on the lipocalin Neural Lazarillo.

    Directory of Open Access Journals (Sweden)

    Matthieu Y Pasco

    Full Text Available In multicellular organisms, insulin/IGF signaling (IIS plays a central role in matching energy needs with uptake and storage, participating in functions as diverse as metabolic homeostasis, growth, reproduction and ageing. In mammals, this pleiotropy of action relies in part on a dichotomy of action of insulin, IGF-I and their respective membrane-bound receptors. In organisms with simpler IIS, this functional separation is questionable. In Drosophila IIS consists of several insulin-like peptides called Dilps, activating a unique membrane receptor and its downstream signaling cascade. During larval development, IIS is involved in metabolic homeostasis and growth. We have used feeding conditions (high sugar diet, HSD that induce an important change in metabolic homeostasis to monitor possible effects on growth. Unexpectedly we observed that HSD-fed animals exhibited severe growth inhibition as a consequence of peripheral Dilp resistance. Dilp-resistant animals present several metabolic disorders similar to those observed in type II diabetes (T2D patients. By exploring the molecular mechanisms involved in Drosophila Dilp resistance, we found a major role for the lipocalin Neural Lazarillo (NLaz, a target of JNK signaling. NLaz expression is strongly increased upon HSD and animals heterozygous for an NLaz null mutation are fully protected from HSD-induced Dilp resistance. NLaz is a secreted protein homologous to the Retinol-Binding Protein 4 involved in the onset of T2D in human and mice. These results indicate that insulin resistance shares common molecular mechanisms in flies and human and that Drosophila could emerge as a powerful genetic system to study some aspects of this complex syndrome.

  3. The role of endoplasmic reticulum stress in hippocampal insulin resistance.

    Science.gov (United States)

    Sims-Robinson, Catrina; Bakeman, Anna; Glasser, Rebecca; Boggs, Janet; Pacut, Crystal; Feldman, Eva L

    2016-03-01

    Metabolic syndrome, which includes hypertension, hyperglycemia, obesity, insulin resistance, and dyslipidemia, has a negative impact on cognitive health. Endoplasmic reticulum (ER) stress is activated during metabolic syndrome, however it is not known which factor associated with metabolic syndrome contributes to this stress. ER stress has been reported to play a role in the development of insulin resistance in peripheral tissues. The role of ER stress in the development of insulin resistance in hippocampal neurons is not known. In the current study, we investigated ER stress in the hippocampus of 3 different mouse models of metabolic syndrome: the C57BL6 mouse on a high fat (HF) diet; apolipoprotein E, leptin, and apolipoprotein B-48 deficient (ApoE 3KO) mice; and the low density lipoprotein receptor, leptin, and apolipoprotein B-48 deficient (LDLR 3KO) mice. We demonstrate that ER stress is activated in the hippocampus of HF mice, and for the first time, in ApoE 3KO mice, but not LDLR 3KO mice. The HF and ApoE 3KO mice are hyperglycemic; however, the LDLR 3KO mice have normal glycemia. This suggests that hyperglycemia may play a role in the activation of ER stress in the hippocampus. Similarly, we also demonstrate that impaired insulin signaling is only present in the HF and ApoE 3KO mice, which suggests that ER stress may play a role in insulin resistance in the hippocampus. To confirm this we pharmacologically induced ER stress with thapsigargin in human hippocampal neurons. We demonstrate for the first time that thapsigargin leads to ER stress and impaired insulin signaling in human hippocampal neurons. Our results may provide a potential mechanism that links metabolic syndrome and cognitive health. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Insulin receptor degradation is accelerated in cultured lymphocytes from patients with genetic syndromes of extreme insulin resistance

    International Nuclear Information System (INIS)

    McElduff, A.; Hedo, J.A.; Taylor, S.I.; Roth, J.; Gorden, P.

    1984-01-01

    The insulin receptor degradation rate was examined in B lymphocytes that were obtained from peripheral blood of normal subjects and patients with several syndromes of extreme insulin resistance. The insulin receptors were surface labeled using Na 125 I/lactoperoxidase and the cells were returned to incubate in growth media. After varying periods of incubation, aliquots of cells were solubilized and the cell content of labeled receptor subunits were measured by immunoprecipitation with anti-receptor antibodies and NaDodSO4/polyacrylamide gel electrophoresis. In cell lines from four patients in whom the number of insulin receptors was reduced by greater than 90%, the rate of receptor loss was greater than normal (t1/2 equals 3.8 +/- 0.9 h vs. 6.5 +/- 1.2 h; mean +/- SD, P less than 0.01). However, a similar acceleration in receptor degradation was seen in cells from five patients with extreme insulin resistance but low-normal insulin receptor concentration (t1/2 equals 4.4 +/- 0.9 h). Thus, all the patients with genetic syndromes of insulin resistance had accelerated receptor degradation, regardless of their receptor concentration. By contrast, insulin receptors on cultured lymphocytes that were obtained from patients with extreme insulin resistance secondary to autoantibodies to the insulin receptor had normal receptor degradation (t1/2 equals 6.1 +/- 1.9 h). We conclude that (a) accelerated insulin receptor degradation is an additional feature of cells from patients with genetic forms of insulin resistance; (b) that accelerated insulin receptor degradation may explain the low-normal receptor concentrations that were seen in some patients with extreme insulin resistance; and (c) that accelerated degradation does not explain the decreased receptor concentration in patients with very low insulin receptor binding and, therefore, by inference, a defect in receptor synthesis must be present in this subgroup

  5. Insulin resistance and postreceptor changes of liver metabolism in fat-fed mice

    DEFF Research Database (Denmark)

    Hedeskov, Carl Jørgen; Capito, Kirsten; Hansen, Svend Erik

    1992-01-01

    Medicinsk biokemi, animal diabetes, insulin resistance, postreceptor defects, liver metabolism, high-fat diet......Medicinsk biokemi, animal diabetes, insulin resistance, postreceptor defects, liver metabolism, high-fat diet...

  6. Cancer-drug induced insulin resistance : Innocent bystander or unusual suspect

    NARCIS (Netherlands)

    Ariaans, G.; de Jong, S.; Gietema, J. A.; Lefrandt, J. D.; de Vries, E. G. E.; Jalving, M.

    Epidemiological and experimental evidence strongly suggests an association between type 2 diabetes mellitus and cancer. Insulin resistance, causing hyperinsulinaemia and eventually hyperglycaemia, appears to increase cancer incidence and disease progression. In addition, insulin resistance seems to

  7. Abdominal adiposity largely explains associations between insulin resistance, hyperglycemia and subclinical atherosclerosis: the NEO study

    NARCIS (Netherlands)

    Gast, K.B.; Smit, J.W.A.; Heijer, M. den; Middeldorp, S.; Rippe, R.C.; Cessie, S. le; Koning, E.J. de; Jukema, J.W.; Rabelink, T.J.; Roos, A. de; Rosendaal, F.R.; Mutsert, R. de; Assendelft, P.; et al.,

    2013-01-01

    OBJECTIVE: The relative importance of insulin resistance and hyperglycemia to the development of atherosclerosis remains unclear. Furthermore, adiposity may be responsible for observed associations. Our aim was to study the relative contributions of adiposity, insulin resistance and hyperglycemia to

  8. Abdominal adiposity largely explains associations between insulin resistance, hyperglycemia and subclinical atherosclerosis: the NEO study

    NARCIS (Netherlands)

    Gast, Karin B.; Smit, Johannes W. A.; den Heijer, Martin; Middeldorp, Saskia; Rippe, Ralph C. A.; le Cessie, Saskia; de Koning, Eelco J. P.; Jukema, J. W.; Rabelink, Ton J.; de Roos, Albert; Rosendaal, Frits R.; de Mutsert, Renée; Rosendaal, F. R.; de Mutsert, R.; Rabelink, T. J.; Smit, J. W. A.; Romijn, J. A.; Rabe, K. F.; de Roos, A.; le Cessie, S.; Hiemstra, P. S.; Kloppenburg, M.; Huizinga, T. W. J.; Pijl, H.; Tamsma, J. T.; de Koning, E. J. P.; Assendelft, W. J. J.; Reitsma, P. H.; van Dijk, K. Willems; de Vries, A. P. J.; Lamb, H. J.; Jazet, I. M.; Dekkers, O. M.; Biermasz, N. R.; Cobbaert, C. M.; Heijer, M. den; Dekker, J. M.; Penninx, B. W.

    2013-01-01

    The relative importance of insulin resistance and hyperglycemia to the development of atherosclerosis remains unclear. Furthermore, adiposity may be responsible for observed associations. Our aim was to study the relative contributions of adiposity, insulin resistance and hyperglycemia to

  9. Expansion and conversion of human pancreatic ductal cells into insulin-secreting endocrine cells.

    Science.gov (United States)

    Lee, Jonghyeob; Sugiyama, Takuya; Liu, Yinghua; Wang, Jing; Gu, Xueying; Lei, Ji; Markmann, James F; Miyazaki, Satsuki; Miyazaki, Jun-Ichi; Szot, Gregory L; Bottino, Rita; Kim, Seung K

    2013-11-19

    Pancreatic islet β-cell insufficiency underlies pathogenesis of diabetes mellitus; thus, functional β-cell replacement from renewable sources is the focus of intensive worldwide effort. However, in vitro production of progeny that secrete insulin in response to physiological cues from primary human cells has proven elusive. Here we describe fractionation, expansion and conversion of primary adult human pancreatic ductal cells into progeny resembling native β-cells. FACS-sorted adult human ductal cells clonally expanded as spheres in culture, while retaining ductal characteristics. Expression of the cardinal islet developmental regulators Neurog3, MafA, Pdx1 and Pax6 converted exocrine duct cells into endocrine progeny with hallmark β-cell properties, including the ability to synthesize, process and store insulin, and secrete it in response to glucose or other depolarizing stimuli. These studies provide evidence that genetic reprogramming of expandable human pancreatic cells with defined factors may serve as a general strategy for islet replacement in diabetes. DOI: http://dx.doi.org/10.7554/eLife.00940.001.

  10. Host Genotype and Gut Microbiome Modulate Insulin Secretion and Diet-Induced Metabolic Phenotypes.

    Science.gov (United States)

    Kreznar, Julia H; Keller, Mark P; Traeger, Lindsay L; Rabaglia, Mary E; Schueler, Kathryn L; Stapleton, Donald S; Zhao, Wen; Vivas, Eugenio I; Yandell, Brian S; Broman, Aimee Teo; Hagenbuch, Bruno; Attie, Alan D; Rey, Federico E

    2017-02-14

    Genetic variation drives phenotypic diversity and influences the predisposition to metabolic disease. Here, we characterize the metabolic phenotypes of eight genetically distinct inbred mouse strains in response to a high-fat/high-sucrose diet. We found significant variation in diabetes-related phenotypes and gut microbiota composition among the different mouse strains in response to the dietary challenge and identified taxa associated with these traits. Follow-up microbiota transplant experiments showed that altering the composition of the gut microbiota modifies strain-specific susceptibility to diet-induced metabolic disease. Animals harboring microbial communities with enhanced capacity for processing dietary sugars and for generating hydrophobic bile acids showed increased susceptibility to metabolic disease. Notably, differences in glucose-stimulated insulin secretion between different mouse strains were partially recapitulated via gut microbiota transfer. Our results suggest that the gut microbiome contributes to the genetic and phenotypic diversity observed among mouse strains and provide a link between the gut microbiome and insulin secretion. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  11. Skeletal muscle lipid metabolism in exercise and insulin resistance

    DEFF Research Database (Denmark)

    Kiens, Bente

    2006-01-01

    Lipids as fuel for energy provision originate from different sources: albumin-bound long-chain fatty acids (LCFA) in the blood plasma, circulating very-low-density lipoproteins-triacylglycerols (VLDL-TG), fatty acids from triacylglycerol located in the muscle cell (IMTG), and possibly fatty acids...... of insulin resistance in skeletal muscle, including possible molecular mechanisms involved, is discussed....

  12. Complement activation, endothelial dysfunction, insulin resistance and chronic heart failure

    DEFF Research Database (Denmark)

    Bjerre, M.; Kistorp, C.; Hansen, T.K.

    2010-01-01

    CRP), endothelial activation (soluble E-selectin, sEsel)), endothelial damage/dysfunction (von Willebrand factor, vWf) and insulin resistance (IR) and prognosis in CHF remains unknown. Design. We investigated the association(s) between plasma sMAC, hsCRP, sEsel, vWf and IR (assessed by homeostatic model assessment...

  13. Associations of erythrocyte fatty acid patterns with insulin resistance

    Science.gov (United States)

    Background: Synergistic and/or additive effects on cardiometabolic risk may be missed by examining individual fatty acids (FA). A pattern analysis may be a more useful approach. As well, it remains unclear whether erythrocyte fatty acid composition relates to insulin resistance among Hispanic/Latino...

  14. Insulin resistance, metabolic syndrome, and lipids in African women

    African Journals Online (AJOL)

    2016-01-27

    Jan 27, 2016 ... high‑density lipoprotein (TG/HDL), total cholesterol (TC)/HDL, and atherogenic index of ... Key words: Insulin resistance, metabolic syndrome, triglycerides, women ... been reported that a TG/HDL ratio of >3.0 is predictive of.

  15. Physical Training Improves Insulin Resistance Syndrome Markers in Obese Adolescents.

    Science.gov (United States)

    Kang, Hyun-Sik; Gutin, Bernard; Barbeau, Paule; Owens, Scott; Lemmon, Christian R.; Allison, Jerry; Litaker, Mark S.; Le, Ngoc-Anh

    2002-01-01

    Tested the hypothesis that physical training (PT), especially high-intensity PT, would favorably affect components of the insulin resistance syndrome (IRS) in obese adolescents. Data on teens randomized into lifestyle education (LSE) alone, LSE plus moderate -intensity PT, and LSE plus high-intensity PT indicated that PT, especially high-intensity…

  16. Alloxan-induced and Insulin-resistant Diabetes Mellitus affect ...

    African Journals Online (AJOL)

    The purpose of this study was to determine the effects of diabetes mellitus and insulin resistance on semen parameters, histology of reproductive organs and serum concentrations of testosterone and luteinizing hormone (LH). Male Sprague-Dawley rats weighing 180 - 200g were made diabetic by intravenous injection of ...

  17. Acanthosis nigricans: A flag for insulin resistance | Venkatswami ...

    African Journals Online (AJOL)

    Objectives: Acanthosis nigricans refers to the velvety, black hyperpigmentation seen in the flexures. It is a cutaneous marker for insulin resistance (IR), some metabolic disorders and rarely malignancy. When secondary to IR, it is asymptomatic, except for the hyperpigmentation. The neck is the most accessible and easiest to ...

  18. Evidence to Support a Putative Role for Insulin Resistance in ...

    African Journals Online (AJOL)

    Introduction: The primary cause of morbidity and mortality in the renal patient is a cardiovascular event. Insulin resistance (IR) contributes to this event by increasing cardiovascular disease (CVD) and accelerating rates of decline in kidney function. Here we review the historical background of IR in patients with chronic ...

  19. Assessing Psychological Insulin Resistance in Type 2 Diabetes

    DEFF Research Database (Denmark)

    Holmes-Truscott, Elizabeth; Pouwer, F; Speight, Jane

    2017-01-01

    PURPOSE OF REVIEW: This study aims to examine the operationalisation of 'psychological insulin resistance' (PIR) among people with type 2 diabetes and to identify and critique relevant measures. RECENT FINDINGS: PIR has been operationalised as (1) the assessment of attitudes or beliefs about...

  20. Neuroendocrinology of insulin resistance : metabolic and endocrine aspects of adiposity

    NARCIS (Netherlands)

    van Dijk, G; de Vries, K; Benthem, L; Nyakas, C; Buwalda, B; Scheurink, AJW

    2003-01-01

    Abdominal obesity is a major risk factor to attract the insulin resistance syndrome. It is proposed that abdominal obesity exposes the liver to elevated levels of free fatty acids, which activate a neuroendocrine reflex, leading to increased circulating levels of glucocorticoids. Besides directly

  1. Dopamine D2 receptors in the pathophysiology of insulin resistance

    NARCIS (Netherlands)

    Leeuw van Weenen, Judith Elisabeth de

    2011-01-01

    Extensive literature links the dopamine receptor D2 to insulin resistance and diabetes mellitus type 2. However, many aspects of the functional relationship remain unclear. In this thesis we focused on unraveling the characteristics of the interplay between dopamine D2 receptors and glucose

  2. Adipocytokine Associations with Insulin Resistance in British South Asians

    Directory of Open Access Journals (Sweden)

    D. R. Webb

    2013-01-01

    Full Text Available Aims. Adipocytokines are implicated in the pathogenesis of type 2 diabetes and may represent identifiable precursors of metabolic disease within high-risk groups. We investigated adiponectin, leptin, and TNF-α and assessed the contribution of these molecules to insulin resistance in south Asians. Hypothesis. South Asians have adverse adipocytokine profiles which associate with an HOMA-derived insulin resistance phenotype. Methods. We measured adipocytokine concentrations in south Asians with newly diagnosed impaired glucose tolerance or Type 2 Diabetes Mellitus in a case-control study. 158 (48.5% males volunteers aged 25–75 years with risk factors for diabetes but no known vascular or metabolic disease provided serum samples for ELISA and bioplex assays. Results. Total adiponectin concentration progressively decreased across the glucose spectrum in both sexes. A reciprocal trend in leptin concentration was observed only in south Asian men. Adiponectin but not leptin independently associated with HOMA-derived insulin resistance after logistic multivariate regression. Conclusion. Diasporic south Asian populations have an adverse adipocytokine profile which deteriorates further with glucose dysregulation. Insulin resistance is inversely associated with adiponectin independent of BMI and waist circumference in south Asians, implying that adipocytokine interplay contributes to the pathogenesis of metabolic disease in this group.

  3. The Effect of a Diet Moderately High in Protein and Fiber on Insulin Sensitivity Measured Using the Dynamic Insulin Sensitivity and Secretion Test (DISST

    Directory of Open Access Journals (Sweden)

    Lisa Te Morenga

    2017-11-01

    Full Text Available Evidence shows that weight loss improves insulin sensitivity but few studies have examined the effect of macronutrient composition independently of weight loss on direct measures of insulin sensitivity. We randomised 89 overweight or obese women to either a standard diet (StdD, that was intended to be low in fat and relatively high in carbohydrate (n = 42 or to a relatively high protein (up to 30% of energy, relatively high fibre (>30 g/day diet (HPHFib (n = 47 for 10 weeks. Advice regarding strict adherence to energy intake goals was not given. Insulin sensitivity and secretion was assessed by a novel method—the Dynamic Insulin Sensitivity and Secretion Test (DISST. Although there were significant improvements in body composition and most cardiometabolic risk factors on HPHFib, insulin sensitivity was reduced by 19.3% (95% CI: 31.8%, 4.5%; p = 0.013 in comparison with StdD. We conclude that the reduction in insulin sensitivity after a diet relatively high in both protein and fibre, despite cardiometabolic improvements, suggests insulin sensitivity may reflect metabolic adaptations to dietary composition for maintenance of glucose homeostasis, rather than impaired metabolism.

  4. Is Insulin Resistance an Intrinsic Defect in Asian Polycystic Ovary Syndrome?

    OpenAIRE

    Lee, Hyejin; Oh, Jee-Young; Sung, Yeon-Ah; Chung, Hyewon

    2013-01-01

    Purpose Approximately 50% to 70% of women with polycystic ovary syndrome (PCOS) have some degree of insulin resistance, and obesity is known to worsen insulin resistance. Many metabolic consequences of PCOS are similar to those of obesity; therefore, defining the cause of insulin resistance in women can be difficult. Our objective was to clarify the factors contributing to insulin resistance in PCOS. Materials and Methods We consecutively recruited 144 women with PCOS [age: 26?5 yr, body mass...

  5. The influence of INS VNTR class III allele on auxological parameters, glucose, insulin, lipids, and adipocytokines secretion in prepubertal children born small for gestational age.

    Science.gov (United States)

    Stawerska, Renata; Szałapska, Małgorzata; Borowiec, Maciej; Antosik, Karolina; Młynarski, Wojciech; Lewiński, Andrzej

    2016-01-01

    The insulin gene variable number of tandem repeats (INS VNTR) class III allele has been implicated in lower birth weight, obesity, and insulin resistance. We assessed its influence on birth weight in the Polish population and on the current body mass and metabolic profile in prepubertal children born small for gestational age (SGA). DNA for genotyping of INS VNTR was available for 123 subjects born SGA and 132 born appropriate for gestational age (AGA). We identified two alleles: class I and class III. Next, in 112 prepubertal (aged: 6.8 ± 1.38 years) SGA children, the auxological measurements, fasting serum C-peptide, triglycerides, cholesterol, ghrelin, leptin, adiponectin, resistin, cortisol, and insulin-like growth factor type I (IGF-I) concentrations, as well as glucose and insulin during oral glucose tolerance test (OGTT), were assessed and insulin resistance indices were calculated. The results were analysed depending on INS VNTR variants. The occurrence of individual INS VNTR variants were similar in the SGA and AGA groups. In prepubertal SGA children, we did not observe any statistical differences as regards birth weight, body mass, lipids, or adipocytokine concentrations among I/I, I/III, and III/III class groups. The concentration of insulin in 120' of OGTT was significantly higher in class III homozygous than in class I homozygous individuals. Variant INS VNTR class III was shown not to be associated in any essential way with birth weight in the Polish population. Among prepubertal SGA children, the presence of INS VNTR class III is related to higher insulin secretion during OGTT. (Endokrynol Pol 2016; 67 (6): 585-591).

  6. Roles of mitochondrial fragmentation and reactive oxygen species in mitochondrial dysfunction and myocardial insulin resistance

    International Nuclear Information System (INIS)

    Watanabe, Tomoyuki; Saotome, Masao; Nobuhara, Mamoru; Sakamoto, Atsushi; Urushida, Tsuyoshi; Katoh, Hideki; Satoh, Hiroshi; Funaki, Makoto; Hayashi, Hideharu

    2014-01-01

    Purpose: Evidence suggests an association between aberrant mitochondrial dynamics and cardiac diseases. Because myocardial metabolic deficiency caused by insulin resistance plays a crucial role in heart disease, we investigated the role of dynamin-related protein-1 (DRP1; a mitochondrial fission protein) in the pathogenesis of myocardial insulin resistance. Methods and Results: DRP1-expressing H9c2 myocytes, which had fragmented mitochondria with mitochondrial membrane potential (ΔΨ m ) depolarization, exhibited attenuated insulin signaling and 2-deoxy-D-glucose (2-DG) uptake, indicating insulin resistance. Treatment of the DRP1-expressing myocytes with Mn(III)tetrakis(1-methyl-4-pyridyl)porphyrin pentachloride (TMPyP) significantly improved insulin resistance and mitochondrial dysfunction. When myocytes were exposed to hydrogen peroxide (H 2 O 2 ), they increased DRP1 expression and mitochondrial fragmentation, resulting in ΔΨ m depolarization and insulin resistance. When DRP1 was suppressed by siRNA, H 2 O 2 -induced mitochondrial dysfunction and insulin resistance were restored. Our results suggest that a mutual enhancement between DRP1 and reactive oxygen species could induce mitochondrial dysfunction and myocardial insulin resistance. In palmitate-induced insulin-resistant myocytes, neither DRP1-suppression nor TMPyP restored the ΔΨ m depolarization and impaired 2-DG uptake, however they improved insulin signaling. Conclusions: A mutual enhancement between DRP1 and ROS could promote mitochondrial dysfunction and inhibition of insulin signal transduction. However, other mechanisms, including lipid metabolite-induced mitochondrial dysfunction, may be involved in palmitate-induced insulin resistance. - Highlights: • DRP1 promotes mitochondrial fragmentation and insulin-resistance. • A mutual enhancement between DRP1 and ROS ipromotes insulin-resistance. • Palmitate increases DRP1 expression and induces insulin-resistance. • Inhibition of DRP or ROS

  7. Roles of mitochondrial fragmentation and reactive oxygen species in mitochondrial dysfunction and myocardial insulin resistance

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Tomoyuki [Internal Medicine III, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192 (Japan); Saotome, Masao, E-mail: msaotome@hama-med.ac.jp [Internal Medicine III, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192 (Japan); Nobuhara, Mamoru; Sakamoto, Atsushi; Urushida, Tsuyoshi; Katoh, Hideki; Satoh, Hiroshi [Internal Medicine III, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192 (Japan); Funaki, Makoto [Clinical Research Center for Diabetes, Tokushima University Hospital, 2-50-1 Kuramoto-cho, Tokushima 770-8503 (Japan); Hayashi, Hideharu [Internal Medicine III, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192 (Japan)

    2014-05-01

    Purpose: Evidence suggests an association between aberrant mitochondrial dynamics and cardiac diseases. Because myocardial metabolic deficiency caused by insulin resistance plays a crucial role in heart disease, we investigated the role of dynamin-related protein-1 (DRP1; a mitochondrial fission protein) in the pathogenesis of myocardial insulin resistance. Methods and Results: DRP1-expressing H9c2 myocytes, which had fragmented mitochondria with mitochondrial membrane potential (ΔΨ{sub m}) depolarization, exhibited attenuated insulin signaling and 2-deoxy-D-glucose (2-DG) uptake, indicating insulin resistance. Treatment of the DRP1-expressing myocytes with Mn(III)tetrakis(1-methyl-4-pyridyl)porphyrin pentachloride (TMPyP) significantly improved insulin resistance and mitochondrial dysfunction. When myocytes were exposed to hydrogen peroxide (H{sub 2}O{sub 2}), they increased DRP1 expression and mitochondrial fragmentation, resulting in ΔΨ{sub m} depolarization and insulin resistance. When DRP1 was suppressed by siRNA, H{sub 2}O{sub 2}-induced mitochondrial dysfunction and insulin resistance were restored. Our results suggest that a mutual enhancement between DRP1 and reactive oxygen species could induce mitochondrial dysfunction and myocardial insulin resistance. In palmitate-induced insulin-resistant myocytes, neither DRP1-suppression nor TMPyP restored the ΔΨ{sub m} depolarization and impaired 2-DG uptake, however they improved insulin signaling. Conclusions: A mutual enhancement between DRP1 and ROS could promote mitochondrial dysfunction and inhibition of insulin signal transduction. However, other mechanisms, including lipid metabolite-induced mitochondrial dysfunction, may be involved in palmitate-induced insulin resistance. - Highlights: • DRP1 promotes mitochondrial fragmentation and insulin-resistance. • A mutual enhancement between DRP1 and ROS ipromotes insulin-resistance. • Palmitate increases DRP1 expression and induces insulin-resistance

  8. Deletion of GPR40 Impairs Glucose-Induced Insulin Secretion In Vivo in Mice Without Affecting Intracellular Fuel Metabolism in Islets

    Energy Technology Data Exchange (ETDEWEB)

    Alquier, Thierry; Peyot, Marie-Line; Latour, M. G.; Kebede, Melkam; Sorensen, Christina M.; Gesta, Stephane; Kahn, C. R.; Smith, Richard D.; Jetton, Thomas L.; Metz, Thomas O.; Prentki, Marc; Poitout, Vincent J.

    2009-11-01

    The G protein-coupled receptor GPR40 mediates fatty-acid potentiation of glucose-stimulated insulin secretion, but its contribution to insulin secretion in vivo and mechanisms of action remain uncertain. This study was aimed to ascertain whether GPR40 controls insulin secretion in vivo and modulates intracellular fuel metabolism in islets. We observed that glucose- and arginine-stimulated insulin secretion, assessed by hyperglycemic clamps, was decreased by approximately 60% in GPR40 knock-out (KO) fasted and fed mice, without changes in insulin sensitivity assessed by hyperinsulinemic-euglycemic clamps. Glucose and palmitate metabolism were not affected by GPR40 deletion. Lipid profiling revealed a similar increase in triglyceride and decrease in lysophosphatidylethanolamine species in WT and KO islets in response to palmitate. These results demonstrate that GPR40 regulates insulin secretion in vivo not only in response to fatty acids but also to glucose and arginine, without altering intracellular fuel metabolism.

  9. Activation of transmembrane bile acid receptor TGR5 stimulates insulin secretion in pancreatic β cells

    International Nuclear Information System (INIS)

    Kumar, Divya P.; Rajagopal, Senthilkumar; Mahavadi, Sunila; Mirshahi, Faridoddin; Grider, John R.; Murthy, Karnam S.; Sanyal, Arun J.

    2012-01-01

    Highlights: ► G protein coupled receptor TGR5 is expressed in mouse and human islets. ► TGR5 is coupled to activation of Gs and Ca 2+ release via cAMP/Epac/PLC-ε pathway. ► Activation of TGR5 by bile salts and selective ligands causes insulin secretion. ► TGR5 could be a potential therapeutic target to treat diabetes. -- Abstract: Bile acids act as signaling molecules and stimulate the G protein coupled receptor, TGR5, in addition to nuclear farnesoid X receptor to regulate lipid, glucose and energy metabolism. Bile acid induced activation of TGR5 in the enteroendocrine cells promotes glucagon like peptide-1 (GLP-1) release, which has insulinotropic effect in the pancreatic β cells. In the present study, we have identified the expression of TGR5 in pancreatic β cell line MIN6 and also in mouse and human pancreatic islets. TGR5 selective ligands, oleanolic acid (OA) and INT-777 selectively activated Gα s and caused an increase in intracellular cAMP and Ca 2+ . OA and INT-777 also increased phosphoinositide (PI) hydrolysis and the increase was blocked by NF449 (a selective Gα s inhibitor) or (U73122) (PI hydrolysis inhibitor). OA, INT-777 and lithocholic acid increased insulin release in MIN6 and human islets and the increase was inhibited by treatment with NF449, (U73122) or BAPTA-AM (chelator of calcium), but not with myristoylated PKI (PKA inhibitor), suggesting that the release is dependent on G s /cAMP/Ca 2+ pathway. 8-pCPT-2′-O-Me-cAMP, a cAMP analog, which activates Epac, but not PKA also stimulated PI hydrolysis. In conclusion, our study demonstrates that the TGR5 expressed in the pancreatic β cells regulates insulin secretion and highlights the importance of ongoing therapeutic strategies targeting TGR5 in the control of glucose homeostasis.

  10. Mitochondrial Pyruvate Carrier 2 Hypomorphism in Mice Leads to Defects in Glucose-Stimulated Insulin Secretion

    Directory of Open Access Journals (Sweden)

    Patrick A. Vigueira

    2014-06-01

    Full Text Available Carrier-facilitated pyruvate transport across the inner mitochondrial membrane plays an essential role in anabolic and catabolic intermediary metabolism. Mitochondrial pyruvate carrier 2 (Mpc2 is believed to be a component of the complex that facilitates mitochondrial pyruvate import. Complete MPC2 deficiency resulted in embryonic lethality in mice. However, a second mouse line expressing an N-terminal truncated MPC2 protein (Mpc2Δ16 was viable but exhibited a reduced capacity for mitochondrial pyruvate oxidation. Metabolic studies demonstrated exaggerated blood lactate concentrations after pyruvate, glucose, or insulin challenge in Mpc2Δ16 mice. Additionally, compared with wild-type controls, Mpc2Δ16 mice exhibited normal insulin sensitivity but elevated blood glucose after bolus pyruvate or glucose injection. This was attributable to reduced glucose-stimulated insulin secretion and was corrected by sulfonylurea KATP channel inhibitor administration. Collectively, these data are consistent with a role for MPC2 in mitochondrial pyruvate import and suggest that Mpc2 deficiency results in defective pancreatic β cell glucose sensing.

  11. Insulin sensitivity and metabolic flexibility following exercise training among different obese insulin-resistant phenotypes.

    Science.gov (United States)

    Malin, Steven K; Haus, Jacob M; Solomon, Thomas P J; Blaszczak, Alecia; Kashyap, Sangeeta R; Kirwan, John P

    2013-11-15

    Impaired fasting glucose (IFG) blunts the reversal of impaired glucose tolerance (IGT) after exercise training. Metabolic inflexibility has been implicated in the etiology of insulin resistance; however, the efficacy of exercise on peripheral and hepatic insulin