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Sample records for gfp-tagged glp-1 receptor

  1. Polarized expression of the GFP-tagged rat V(1a) vasopressin receptor.

    Science.gov (United States)

    Campos, D M; Reyes, C E; Sarmiento, J; Navarro, J; González, C B

    2001-11-30

    We investigated the targeting of the V(1a) receptor fused with the green fluorescence protein (V(1a)R-GFP) in polarized MDCK cells. Cells expressing V(1a)R-GFP displayed binding to vasopressin (AVP) and AVP-induced calcium responses, similar to cells expressing the wild-type V1a receptor. Interestingly, as with the wild-type V(1a)R, V(1a)R-GFP is preferentially distributed in the basolateral side of MDCK cells as monitored by confocal microscopy. Furthermore, AVP induced internalization of GFP-tagged receptors. Therefore, the GFP-tagged V(1a) receptor retains all the sorting signals of the wild-type receptor and offers an excellent system to elucidate the mechanisms of cell trafficking of V(1a) receptors.

  2. Emerging GLP-1 receptor agonists

    DEFF Research Database (Denmark)

    Lund, Asger; Knop, Filip K; Vilsbøll, Tina

    2011-01-01

    and liraglutide, as well as the emerging GLP-1R agonists including the long-acting compounds. Expert opinion: An emerging therapeutic trend toward initial or early combination therapy with metformin- and incretin-based therapy is anticipated for patients with type 2 diabetes. GLP-1-based therapy has so far proven...... development may improve the effects of GLP-1 even further with optimized pharmacokinetic profiles resulting in fewer side effects. Meta-analyses have shown promising effects on cardiovascular disease and data from ongoing multicenter trials with cardiovascular endpoints are expected in 2015....

  3. Emerging GLP-1 receptor agonists

    DEFF Research Database (Denmark)

    Lund, Asger; Knop, Filip K; Vilsbøll, Tina

    2011-01-01

    development may improve the effects of GLP-1 even further with optimized pharmacokinetic profiles resulting in fewer side effects. Meta-analyses have shown promising effects on cardiovascular disease and data from ongoing multicenter trials with cardiovascular endpoints are expected in 2015....

  4. Radiolabelled GLP-1 receptor antagonist binds to GLP-1 receptor-expressing human tissues

    Energy Technology Data Exchange (ETDEWEB)

    Waser, Beatrice; Reubi, Jean Claude [University of Berne, Division of Cell Biology and Experimental Cancer Research, Institute of Pathology, PO Box 62, Berne (Switzerland)

    2014-06-15

    Radiolabelled glucagon-like peptide 1 (GLP-1) receptor agonists have recently been shown to successfully image benign insulinomas in patients. For the somatostatin receptor targeting of tumours, however, it was recently reported that antagonist tracers were superior to agonist tracers. The present study therefore evaluated various forms of the {sup 125}iodinated-Bolton-Hunter (BH)-exendin(9-39) antagonist tracer for the in vitro visualization of GLP-1 receptor-expressing tissues in rats and humans and compared it with the agonist tracer {sup 125}I-GLP-1(7-36)amide. Receptor autoradiography studies with {sup 125}I-GLP-1(7-36)amide agonist or {sup 125}I-BH-exendin(9-39) antagonist radioligands were performed in human and rat tissues. The antagonist {sup 125}I-BH-exendin(9-39) labelled at lysine 19 identifies all human and rat GLP-1 target tissues and GLP-1 receptor-expressing tumours. Binding is of high affinity and is comparable in all tested tissues in its binding properties with the agonist tracer {sup 125}I-GLP-1(7-36)amide. For comparison, {sup 125}I-BH-exendin(9-39) with the BH labelled at lysine 4 did identify the GLP-1 receptor in rat tissues but not in human tissues. The GLP-1 receptor antagonist exendin(9-39) labelled with {sup 125}I-BH at lysine 19 is an excellent GLP-1 radioligand that identifies human and rat GLP-1 receptors in normal and tumoural tissues. It may therefore be the molecular basis to develop suitable GLP-1 receptor antagonist radioligands for in vivo imaging of GLP-1 receptor-expressing tissues in patients. (orig.)

  5. Radiolabelled GLP-1 receptor antagonist binds to GLP-1 receptor-expressing human tissues

    International Nuclear Information System (INIS)

    Waser, Beatrice; Reubi, Jean Claude

    2014-01-01

    Radiolabelled glucagon-like peptide 1 (GLP-1) receptor agonists have recently been shown to successfully image benign insulinomas in patients. For the somatostatin receptor targeting of tumours, however, it was recently reported that antagonist tracers were superior to agonist tracers. The present study therefore evaluated various forms of the 125 iodinated-Bolton-Hunter (BH)-exendin(9-39) antagonist tracer for the in vitro visualization of GLP-1 receptor-expressing tissues in rats and humans and compared it with the agonist tracer 125 I-GLP-1(7-36)amide. Receptor autoradiography studies with 125 I-GLP-1(7-36)amide agonist or 125 I-BH-exendin(9-39) antagonist radioligands were performed in human and rat tissues. The antagonist 125 I-BH-exendin(9-39) labelled at lysine 19 identifies all human and rat GLP-1 target tissues and GLP-1 receptor-expressing tumours. Binding is of high affinity and is comparable in all tested tissues in its binding properties with the agonist tracer 125 I-GLP-1(7-36)amide. For comparison, 125 I-BH-exendin(9-39) with the BH labelled at lysine 4 did identify the GLP-1 receptor in rat tissues but not in human tissues. The GLP-1 receptor antagonist exendin(9-39) labelled with 125 I-BH at lysine 19 is an excellent GLP-1 radioligand that identifies human and rat GLP-1 receptors in normal and tumoural tissues. It may therefore be the molecular basis to develop suitable GLP-1 receptor antagonist radioligands for in vivo imaging of GLP-1 receptor-expressing tissues in patients. (orig.)

  6. Novel GLP-1 fusion chimera as potent long acting GLP-1 receptor agonist.

    Directory of Open Access Journals (Sweden)

    Qinghua Wang

    2010-09-01

    Full Text Available GLP-1 has a variety of anti-diabetic effects. However, native GLP-1 is not suitable for therapy of diabetes due to its short half-life (t1/2168 h. Intraperitoneal glucose tolerance test (IPGTT in mice showed that GLP-1/hIgG2 significantly decreased glucose excursion. Furthermore, IPGTT performed on mice one week after a single drug-injection also displayed significantly reduced glucose excursion, indicating that GLP-1/hIgG2 fusion protein has long-lasting effects on the modulation of glucose homeostasis. GLP-1/hIgG2 was found to be effective in reducing the incidence of diabetes in multiple-low-dose streptozotocin-induced type 1 diabetes in mice. Together, the long-lasting bioactive GLP-1/hIgG2 retains native GLP-1 activities and thus may serve as a potent GLP-1 receptor agonist.

  7. Combining GLP-1 receptor agonists with insulin

    DEFF Research Database (Denmark)

    Holst, Jens Juul; Vilsbøll, T

    2013-01-01

    Due to the increasing prevalence of type 2 diabetes mellitus (T2DM), the emergent trend towards diagnosis in younger patients and the progressive nature of this disease, many more patients than before now require insulin to maintain glycaemic control. However, there is a degree of inertia among...... physicians and patients regarding the initiation and intensification of insulin therapy, in part due to concerns about the associated weight gain and increased risk of hypoglycaemia. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) increase insulin release and suppress glucagon secretion in a glucose......, compared with insulin, the antihyperglycaemic efficacy of GLP-1RAs is limited. The combination of a GLP-1RA and insulin might thus be highly effective for optimal glucose control, ameliorating the adverse effects typically associated with insulin. Data from clinical studies support the therapeutic...

  8. GLP-1 receptor localization in monkey and human tissue

    DEFF Research Database (Denmark)

    Pyke, Charles; Heller, R Scott; Kirk, Rikke K

    2014-01-01

    and increase heart rate. Using a new monoclonal antibody for immunohistochemistry, we detected GLP-1 receptor (GLP-1R) in important target organs in humans and monkeys. In the pancreas, GLP-1R was predominantly localized in β-cells with a markedly weaker expression in acinar cells. Pancreatic ductal epithelial...

  9. Cardiovascular safety and benefits of GLP-1 receptor agonists

    DEFF Research Database (Denmark)

    Dalsgaard, Niels B; Brønden, Andreas; Lauritsen, Tina Vilsbøll

    2017-01-01

    INTRODUCTION: Glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1RAs) constitute a class of drugs for the treatment of type 2 diabetes, and currently, six different GLP-1RAs are approved. Besides improving glycemic control, the GLP-1RAs have other beneficial effects such as weight loss...... and a low risk of hypoglycemia. Treatment with the GLP-1RA lixisenatide has been shown to be safe in patients with type 2 diabetes and recent acute coronary syndrome. Furthermore, liraglutide and semaglutide have been shown to reduce cardiovascular (CV) disease (CVD) risk in type 2 diabetes patients...

  10. [Safety and tolerability of GLP-1 receptor agonists].

    Science.gov (United States)

    Soldevila, Berta; Puig-Domingo, Manel

    2014-09-01

    Glucagon-like peptide-1 receptor agonists (GLP-1ra) are a new group of drugs with a glucose-lowering action due to their incretin effect. The GLP-1 receptor is expressed in various human tissues, which could be related to the pleiotropic effects of human GLP-1, as well as to the adverse effects described in patients treated with GLP-1ra. The risk of hypoglycaemia is low, which is one of the main considerations in the safety of this family of compounds and is also important to patients with diabetes. The most frequent adverse effect is nausea, which usually occurs at the start of treatment and is transient in 20-60% of affected patients. This article also reviews the information available on antibody formation, the potential effect on the thyroid gland, and the controversial association between this group of drugs with pancreatitis and cancer. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  11. Endocytosis of a functionally enhanced GFP-tagged transferrin receptor in CHO cells.

    Directory of Open Access Journals (Sweden)

    Qi He

    Full Text Available The endocytosis of transferrin receptor (TfR has served as a model to study the receptor-targeted cargo delivery system for cancer therapy for many years. To accurately evaluate and optically measure this TfR targeting delivery in vitro, a CHO cell line with enhanced green fluorescent protein (EGFP-tagged human TfR was established. A chimera of the hTfR and EGFP was engineered by fusing EGFP to the amino terminus of hTfR. Data were provided to demonstrate that hTfR-EGFP chimera was predominantly localized on the plasma membrane with some intracellular fluorescent structures on CHO cells and the EGFP moiety did not affect the endocytosis property of hTfR. Receptor internalization occurred similarly to that of HepG2 cells expressing wild-type hTfR. The internalization percentage of this chimeric receptor was about 81 ± 3% of wild type. Time-dependent co-localization of hTfR-EGFP and PE-conjugated anti-hTfR mAb in living cells demonstrated the trafficking of mAb-receptor complexes through the endosomes followed by segregation of part of the mAb and receptor at the late stages of endocytosis. The CHO-hTfR cells preferentially took up anti-hTfR mAb conjugated nanoparticles. This CHO-hTfR cell line makes it feasible for accurate evaluation and visualization of intracellular trafficking of therapeutic agents conjugated with transferrin or Abs targeting the hTfRs.

  12. [Effects of GLP-1 receptor agonists on carbohydrate metabolism control].

    Science.gov (United States)

    Fernández-García, José Carlos; Colomo, Natalia; Tinahones, Francisco José

    2014-09-01

    Glucagon-like peptide-1 (GLP-1) receptor agonists are a new group of drugs for the treatment of type 2 diabetes mellitus (DM2). In the present article, we review the available evidence on the efficacy of GLP-1 receptor agonists as glucose-lowering agents, their place in therapeutic algorithms, and the clinical factors associated with a favorable treatment response. Finally, we describe the clinical characteristics of patients who may benefit from these drugs. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  13. Differential structural properties of GLP-1 and exendin-4 determine their relative affinity for the GLP-1 receptor N-terminal extracellular domain.

    Science.gov (United States)

    Runge, Steffen; Schimmer, Susann; Oschmann, Jan; Schiødt, Christine Bruun; Knudsen, Sanne Möller; Jeppesen, Claus Bekker; Madsen, Kjeld; Lau, Jesper; Thøgersen, Henning; Rudolph, Rainer

    2007-05-15

    Glucagon-like peptide-1 (GLP-1) and exendin-4 (Ex4) are homologous peptides with established potential for treatment of type 2 diabetes. They bind and activate the pancreatic GLP-1 receptor (GLP-1R) with similar affinity and potency and thereby promote insulin secretion in a glucose-dependent manner. GLP-1R belongs to family B of the seven transmembrane G-protein coupled receptors. The N-terminal extracellular domain (nGLP-1R) is a ligand binding domain with differential affinity for Ex4 and GLP-1: low affinity for GLP-1 and high affinity for exendin-4. The superior affinity of nGLP-1R for Ex4 was previously explained by an additional interaction between nGLP-1R and the C-terminal Trp-cage of Ex4. In this study we have combined biophysical and pharmacological approaches thus relating structural properties of the ligands in solution to their relative binding affinity for nGLP-1R. We used both a tracer competition assay and ligand-induced thermal stabilization of nGLP-1R to measure the relative affinity of full length, truncated, and chimeric ligands for soluble refolded nGLP-1R. The ligands in solution and the conformational consequences of ligand binding to nGLP-1R were characterized by circular dichroism and fluorescence spectroscopy. We found a correlation between the helical content of the free ligands and their relative binding affinity for nGLP-1R, supporting the hypothesis that the ligands are helical at least in the segment that binds to nGLP-1R. The Trp-cage of Ex4 was not necessary to maintain a superior helicity of Ex4 compared to GLP-1. The results suggest that the differential affinity of nGLP-1R is explained almost entirely by divergent residues in the central part of the ligands: Leu10-Gly30 of Ex4 and Val16-Arg36 of GLP-1. In view of our results it appears that the Trp-cage plays only a minor role for the interaction between Ex4 and nGLP-1R and for the differential affinity of nGLP-1R for GLP-1 and Ex4.

  14. Functional importance of GLP-1 receptor species and expression levels in cell lines.

    Science.gov (United States)

    Knudsen, Lotte Bjerre; Hastrup, Sven; Underwood, Christina Rye; Wulff, Birgitte Schjellerup; Fleckner, Jan

    2012-04-10

    Of the mammalian species, only the GLP-1 receptors of rat and human origin have been described and characterized. Here, we report the cloning of the homologous GLP-1 receptors from mouse, rabbit, pig, cynomolgus monkey and chimp. The GLP-1 receptor is highly conserved across species, thus underlining the physiological importance of the peptide hormone and its receptor across a wide range of mammals. We expressed the receptors by stable transfection of BHK cells, both in cell lines with high expression levels of the cloned receptors, as well as in cell lines with lower expression levels, more comparable to endogenous expression of these receptors. High expression levels of cloned GLP-1 receptors markedly increased the potency of GLP-1 and other high affinity ligands, whereas the K(d) values were not affected. For a low affinity ligand like the ago-allosteric modulator Compound 2, expression levels of the human GLP-1 receptor were important for maximal efficacy as well as potency. The two natural metabolites of GLP-1, GLP-1(9-37) and GLP-1(9-36)amide were agonists when tested on a cell line with high expression of the recombinant human GLP-1 receptor, whereas they behaved as (low potent) antagonists on a cell line that expressed the receptor endogenously, as well as cells expressing a moderate level of the recombinant human GLP-1 receptor. The amide form was a more potent agonist than the free acid from. In conclusion, receptor expression level is an important parametre for selecting cell lines with cloned GLP-1 receptors for functional characterization of physiological and pharmaceutical ligands. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Value of the radiolabelled GLP-1 receptor antagonist exendin(9-39) for targeting of GLP-1 receptor-expressing pancreatic tissues in mice and humans

    International Nuclear Information System (INIS)

    Waser, Beatrice; Reubi, Jean Claude

    2011-01-01

    Radiolabelled glucagon-like peptide 1 (GLP-1) receptor agonists have recently been shown to successfully image benign insulinomas in patients. Moreover, it was recently reported that antagonist tracers were superior to agonist tracers for somatostatin and gastrin-releasing peptide receptor targeting of tumours. The present preclinical study determines therefore the value of an established GLP-1 receptor antagonist for the in vitro visualization of GLP-1 receptor-expressing tissues in mice and humans. Receptor autoradiography studies with 125 I-GLP-1(7-36)amide agonist or 125 I-Bolton-Hunter-exendin(9-39) antagonist radioligands were performed in mice pancreas and insulinomas as well as in human insulinomas; competition experiments were performed in the presence of increasing concentration of GLP-1(7-36)amide or exendin(9-39). The antagonist 125 I-Bolton-Hunter-exendin(9-39) labels mouse pancreatic β-cells and mouse insulinomas, but it does not label human pancreatic β-cells and insulinomas. High affinity displacement (IC 50 approximately 2 nM) is observed in mouse β-cells and insulinomas with either the exendin(9-39) antagonist or GLP-1(7-36)amide agonist. For comparison, the agonist 125 I-GLP-1(7-36)amide intensively labels mouse pancreatic β-cells, mouse insulinoma and human insulinomas; high affinity displacement is observed for the GLP-1(7-36)amide in all tissues; however, a 5 and 20 times lower affinity is found for exendin(9-39) in the mouse and human tissues, respectively. This study reports a species-dependent behaviour of the GLP-1 receptor antagonist exendin(9-39) that can optimally target GLP-1 receptors in mice but not in human tissue. Due to its overly low binding affinity, this antagonist is an inadequate targeting agent for human GLP-1 receptor-expressing tissues, as opposed to the GLP-1 receptor agonist, GLP-1(7-36)amide. (orig.)

  16. Value of the radiolabelled GLP-1 receptor antagonist exendin(9-39) for targeting of GLP-1 receptor-expressing pancreatic tissues in mice and humans

    Energy Technology Data Exchange (ETDEWEB)

    Waser, Beatrice; Reubi, Jean Claude [University of Berne, Division of Cell Biology and Experimental Cancer Research, Institute of Pathology, P.O. Box 62, Bern (Switzerland)

    2011-06-15

    Radiolabelled glucagon-like peptide 1 (GLP-1) receptor agonists have recently been shown to successfully image benign insulinomas in patients. Moreover, it was recently reported that antagonist tracers were superior to agonist tracers for somatostatin and gastrin-releasing peptide receptor targeting of tumours. The present preclinical study determines therefore the value of an established GLP-1 receptor antagonist for the in vitro visualization of GLP-1 receptor-expressing tissues in mice and humans. Receptor autoradiography studies with {sup 125}I-GLP-1(7-36)amide agonist or {sup 125}I-Bolton-Hunter-exendin(9-39) antagonist radioligands were performed in mice pancreas and insulinomas as well as in human insulinomas; competition experiments were performed in the presence of increasing concentration of GLP-1(7-36)amide or exendin(9-39). The antagonist {sup 125}I-Bolton-Hunter-exendin(9-39) labels mouse pancreatic {beta}-cells and mouse insulinomas, but it does not label human pancreatic {beta}-cells and insulinomas. High affinity displacement (IC{sub 50} approximately 2 nM) is observed in mouse {beta}-cells and insulinomas with either the exendin(9-39) antagonist or GLP-1(7-36)amide agonist. For comparison, the agonist {sup 125}I-GLP-1(7-36)amide intensively labels mouse pancreatic {beta}-cells, mouse insulinoma and human insulinomas; high affinity displacement is observed for the GLP-1(7-36)amide in all tissues; however, a 5 and 20 times lower affinity is found for exendin(9-39) in the mouse and human tissues, respectively. This study reports a species-dependent behaviour of the GLP-1 receptor antagonist exendin(9-39) that can optimally target GLP-1 receptors in mice but not in human tissue. Due to its overly low binding affinity, this antagonist is an inadequate targeting agent for human GLP-1 receptor-expressing tissues, as opposed to the GLP-1 receptor agonist, GLP-1(7-36)amide. (orig.)

  17. Treatment potential of the GLP-1 receptor agonists in type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Østergaard, L; Frandsen, Christian S.; Madsbad, S

    2016-01-01

    Over the last decade, the discovery of glucagon-like peptide 1 receptor agonists (GLP-1 RAs) has increased the treatment options for patients with type 2 diabetes mellitus (T2DM). GLP-1 RAs mimic the effects of native GLP-1, which increases insulin secretion, inhibits glucagon secretion, increases...... satiety and slows gastric emptying. This review evaluates the phase III trials for all approved GLP-1 RAs and reports that all GLP-1 RAs decrease HbA1c, fasting plasma glucose, and lead to a reduction in body weight in the majority of trials. The most common adverse events are nausea and other...... gastrointestinal discomfort, while hypoglycaemia is rarely reported when GLP-1 RAs not are combined with sulfonylurea or insulin. Treatment options in the near future will include co-formulations of basal insulin and a GLP-1 RA....

  18. Activation of GLP-1 Receptor Promotes Bone Marrow Stromal Cell Osteogenic Differentiation through β-Catenin

    Directory of Open Access Journals (Sweden)

    Jingru Meng

    2016-04-01

    Full Text Available Glucagon-like peptide 1 (GLP-1 plays an important role in regulating bone remodeling, and GLP-1 receptor agonist shows a positive relationship with osteoblast activity. However, GLP-1 receptor is not found in osteoblast, and the mechanism of GLP-1 receptor agonist on regulating bone remodeling is unclear. Here, we show that the GLP-1 receptor agonist exendin-4 (Ex-4 promoted bone formation and increased bone mass and quality in a rat unloading-induced bone loss model. These functions were accompanied by an increase in osteoblast number and serum bone formation markers, while the adipocyte number was decreased. Furthermore, GLP-1 receptor was detected in bone marrow stromal cells (BMSCs, but not in osteoblast. Activation of GLP-1 receptor by Ex-4 promoted the osteogenic differentiation and inhibited BMSC adipogenic differentiation through regulating PKA/β-catenin and PKA/PI3K/AKT/GSK3β signaling. These findings reveal that GLP-1 receptor regulates BMSC osteogenic differentiation and provide a molecular basis for therapeutic potential of GLP-1 against osteoporosis.

  19. Rate of Homologous Desensitization and Internalization of the GLP-1 Receptor.

    Science.gov (United States)

    Shaaban, Ghina; Oriowo, Mabayoje; Al-Sabah, Suleiman

    2016-12-26

    The glucagon-like peptide-1 receptor (GLP-1R) is an important target in the treatment of type 2 diabetes mellitus. The aim of this study was to compare the rate of agonist stimulated desensitization and internalization of GLP-1R. To this end, an N-terminally myc-tagged GLP-1R was stably expressed in HEK-293 cells. Homologous desensitization was assessed by measuring the cAMP response to agonist stimulation following pre-incubation with agonist for up to 120 min. Receptor internalization was monitored using an indirect ELISA-based method and confocal microscopy. Pre-incubation with GLP-1 resulted in a time-dependent loss of response to a second stimulation. Washing cells following pre-incubation failed to bring cAMP levels back to basal. Taking this into account, two desensitization rates were calculated: "apparent" (t 1/2 = 19.27 min) and "net" (t 1/2 = 2.99 min). Incubation of cells with GLP-1 also resulted in a time-dependent loss of receptor cell surface expression (t 1/2 = 2.05 min). Rapid agonist-stimulated internalization of GLP-1R was confirmed using confocal microscopy. Stimulation of GLP-1R with GLP-1 results in rapid desensitization and internalization of the receptor. Interestingly, the rate of "net" desensitization closely matches the rate of internalization. Our results suggest that agonist-bound GLP-1R continues to generate cAMP after it has been internalized.

  20. GLP-1 receptor stimulation depresses heart rate variability and inhibits neurotransmission to cardiac vagal neurons.

    Science.gov (United States)

    Griffioen, Kathleen J; Wan, Ruiqian; Okun, Eitan; Wang, Xin; Lovett-Barr, Mary Rachael; Li, Yazhou; Mughal, Mohamed R; Mendelowitz, David; Mattson, Mark P

    2011-01-01

    glucagon-like peptide 1 (GLP-1) is an incretin hormone released from the gut in response to food intake. Whereas GLP-1 acts in the periphery to inhibit glucagon secretion and stimulate insulin release, it also acts in the central nervous system to mediate autonomic control of feeding, body temperature, and cardiovascular function. Because of its role as an incretin hormone, GLP-1 receptor analogs are used as a treatment for type 2 diabetes. Central or peripheral administration of GLP-1 increases blood pressure and heart rate, possibly by activating brainstem autonomic nuclei and increasing vagus nerve activity. However, the mechanism(s) by which GLP-1 receptor stimulation affects cardiovascular function are unknown. We used the long-lasting GLP-1 receptor agonist Exendin-4 (Ex-4) to test the hypothesis that GLP-1 signalling modulates central parasympathetic control of heart rate. using a telemetry system, we assessed heart rate in mice during central Ex-4 administration. Heart rate was increased by both acute and chronic central Ex-4 administration. Spectral analysis indicated that the high frequency and low frequency powers of heart rate variability were diminished by Ex-4 treatment. Finally, Ex-4 decreased both excitatory glutamatergic and inhibitory glycinergic neurotransmission to preganglionic parasympathetic cardiac vagal neurons. these data suggest that central GLP-1 receptor stimulation diminishes parasympathetic modulation of the heart thereby increasing heart rate.

  1. GLP-1 Receptor Activation Modulates Appetite- and Reward-Related Brain Areas in Humans

    NARCIS (Netherlands)

    van Bloemendaal, L.; IJzerman, R.G.; ten Kulve, J.S.; Barkhof, F.; Konrad, R.J.; Drent, M.L.; Veltman, D.J.; Diamant, M.

    2014-01-01

    Gut-derived hormones, such as GLP-1, have been proposed to relay information to the brain to regulate appetite. GLP-1 receptor agonists, currently used for the treatment of type 2 diabetes (T2DM), improve glycemic control and stimulate satiety, leading to decreases in food intake and body weight. We

  2. Development of a cysteine-deprived and C-terminally truncated GLP-1 receptor

    DEFF Research Database (Denmark)

    Underwood, Christina Rye; Knudsen, Lotte Bjerre; Garibay, Patrick W.

    2013-01-01

    The glucagon-like peptide-1 receptor (GLP-1R) belongs to family B of the G-protein coupled receptors (GPCRs), and has become a promising target for the treatment of type 2 diabetes. Here we describe the development and characterization of a fully functional cysteine-deprived and C......-terminally truncated GLP-1R. Single cysteines were initially substituted with alanine, and functionally redundant cysteines were subsequently changed simultaneously. Our results indicate that Cys174, Cys226, Cys296 and Cys403 are important for the GLP-1-mediated response, whereas Cys236, Cys329, Cys341, Cys347, Cys438...... that the membrane proximal part of the C-terminal is involved in receptor expression at the cell surface. The results show that seven cysteines and more than half of the C-terminal tail can be removed from GLP-1R without compromising GLP-1 binding or function....

  3. Role and development of GLP-1 receptor agonists in the management of diabetes

    Directory of Open Access Journals (Sweden)

    Chee W Chia

    2009-05-01

    Full Text Available Chee W Chia, Josephine M EganNational Institutes of Health, National Institute on Aging, Intramural Research Program, Baltimore, Maryland, USAAbstract: Glucagon-like peptide-1 (GLP-1 is a hormone secreted from enteroendocrine L cells of the intestine in response to food. Exogenous GLP-1 administration at pharmacological doses results in many effects that are beneficial for treating type 2 diabetes, these include: (1 an increase in insulin secretion from β cells; (2 a suppression of glucagon secretion from α cells in the presence of hyperglycemia but not hypoglycemia; (3 a delay in gastric emptying and gut motility which in turns delays absorption of ingested nutrients and dampens post-prandial glucose excursion; and (4 an increase in the duration of postprandial satiety therefore suppressing appetite and decreasing food intake which eventually leads to weight loss. However, GLP-1 is subject to rapid enzymatic degradation, and therefore, not suitable for long-term treatment. A synthetic enzyme-resistant GLP-1 receptor agonist that reproduces the biological effects of GLP-1 is in use and more are under development. This review aims at providing a summary of the properties of GLP-1 and the development of GLP-1-based therapies for treatment of diabetes.Keywords: incretin, GLP-1, GLP-1R agonist, diabetes

  4. Purslane Effect on GLP-1 and GLP-1 receptor in type 2 diabetes

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    Roja Daliri

    2013-01-01

    Full Text Available Abstract:Background: The aim of this study was to examine the effect of purslane seeds in glucagon-like peptide-1 concentration and glucagon-like peptide-1 receptor in women with diabetes.Methods: This was a quasi-experimental study. The population was consisted of the city of Sari where diabetic women with diabetes II who had no history of using purslane seeds. All individuals used the same dose of metformin under the specialist supervision. Among these individuals, 16 were assigned at random to Purslane group and control group. The purslane group consumed 2.5 grams Purslane with lunch and along with 5 grams of purslane (Portulaca oleracea seeds 7.5 g daily with dinner meals twice daily for 8 weeks. Blood sample was taken before and after 8 weeks, after 12 hours of fasting to 5 ml of the left brachial vein.Results: After 8 weeks using purslane seeds in the experimental group, a significant increase was seen in glucagon-like peptide-1 concentrations (p<0.007, but there was no significant difference in the concentration of glucagon-like peptide-1 receptor (p <0.455. No significant relationship was found between changes in glucagon-like peptide-1 and its receptor.Conclusion: The use of purslane seeds improved Type II diabetes; therefore it can be effective in improving the health of women with diabetes.

  5. Nutrient Induced Type 2 and Chemical Induced Type 1 Experimental Diabetes Differently Modulate Gastric GLP-1 Receptor Expression

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    Olga Bloch

    2015-01-01

    Full Text Available T2DM patients demonstrate reduced GLP-1 receptor (GLP-1R expression in their gastric glands. Whether induced T2DM and T1DM differently affect the gastric GLP-1R expression is not known. This study assessed extrapancreatic GLP-1R system in glandular stomach of rodents with different types of experimental diabetes. T2DM and T1DM were induced in Psammomys obesus (PO by high-energy (HE diet and by streptozotocin (STZ in Sprague Dawly (SD rats, respectively. GLP-1R expression was determined in glandular stomach by RT PCR and immunohistomorphological analysis. The mRNA expression and cellular association of the GLP-1R in principal glands were similar in control PO and SD rats. However, nutrient and chemical induced diabetes resulted in opposite alterations of glandular GLP-1R expression. Diabetic PO demonstrated increased GLP-1R mRNA expression, intensity of cellular GLP-1R immunostaining, and frequency of GLP-1R positive cells in the neck area of principal glands compared with controls. In contrast, SD diabetic rats demonstrated decreased GLP-1 mRNA, cellular GLP-1R immunoreactivity, and frequency of GLP-1R immunoreactive cells in the neck area compared with controls. In conclusion, nutrient and chemical induced experimental diabetes result in distinct opposite alterations of GLP-1R expression in glandular stomach. These results suggest that induced T1DM and T2DM may differently modulate GLP-1R system in enteropancreatic axis.

  6. Transmembrane α-Helix 2 and 7 Are Important for Small Molecule-Mediated Activation of the GLP-1 Receptor

    DEFF Research Database (Denmark)

    Underwood, Christina Rye; Møller Knudsen, Sanne; Schjellerup Wulff, Birgitte

    2011-01-01

    Glucagon-like peptide-1 (GLP-1) activates the GLP-1 receptor (GLP-1R), which belongs to family B of the G-protein-coupled receptors. We previously identified a selective small molecule ligand, compound 2, that acted as a full agonist and allosteric modulator of GLP-1R. In this study, the structur......Glucagon-like peptide-1 (GLP-1) activates the GLP-1 receptor (GLP-1R), which belongs to family B of the G-protein-coupled receptors. We previously identified a selective small molecule ligand, compound 2, that acted as a full agonist and allosteric modulator of GLP-1R. In this study......, the structurally related small molecule, compound 3, stimulated cAMP production from GLP-1R, but not from the homologous glucagon receptor (GluR). The receptor selectivity encouraged a chimeric receptor approach to identify domains important for compound 3-mediated activation of GLP-1R. A subsegment of the GLP-1R...... transmembrane domain containing TM2 to TM5 was sufficient to transfer compound 3 responsiveness to GluR. Therefore, divergent residues in this subsegment of GLP-1R and GluR are responsible for the receptor selectivity of compound 3. Functional analyses of other chimeric receptors suggested that the existence...

  7. The glucagon-like peptide 1 (GLP-1) receptor agonist exendin-4 reduces cocaine self-administration in mice

    DEFF Research Database (Denmark)

    Sorensen, Gunnar; Reddy, India A.; Weikop, Pia

    2015-01-01

    implicating central GLP-1 receptors in these responses. The present results demonstrate that the GLP-1 system modulates cocaine's effects on behavior and dopamine homeostasis, indicating that the GLP-1 receptor may be a novel target for the pharmacological treatment of drug addiction....

  8. Hindbrain GLP-1 receptor mediation of cisplatin-induced anorexia and nausea.

    Science.gov (United States)

    De Jonghe, Bart C; Holland, Ruby A; Olivos, Diana R; Rupprecht, Laura E; Kanoski, Scott E; Hayes, Matthew R

    2016-01-01

    While chemotherapy-induced nausea and vomiting are clinically controlled in the acute (anorexia, nausea, fatigue, and other illness-type behaviors during the delayed phase (>24 h) of chemotherapy are largely uncontrolled. As the hindbrain glucagon-like peptide-1 (GLP-1) system contributes to energy balance and mediates aversive and stressful stimuli, here we examine the hypothesis that hindbrain GLP-1 signaling mediates aspects of chemotherapy-induced nausea and reductions in feeding behavior in rats. Specifically, hindbrain GLP-1 receptor (GLP-1R) blockade, via 4th intracerebroventricular (ICV) exendin-(9-39) injections, attenuates the anorexia, body weight reduction, and pica (nausea-induced ingestion of kaolin clay) elicited by cisplatin chemotherapy during the delayed phase (48 h) of chemotherapy-induced nausea. Additionally, the present data provide evidence that the central GLP-1-producing preproglucagon neurons in the nucleus tractus solitarius (NTS) of the caudal brainstem are activated by cisplatin during the delayed phase of chemotherapy-induced nausea, as cisplatin led to a significant increase in c-Fos immunoreactivity in NTS GLP-1-immunoreactive neurons. These data support a growing body of literature suggesting that the central GLP-1 system may be a potential pharmaceutical target for adjunct anti-emetics used to treat the delayed-phase of nausea and emesis, anorexia, and body weight loss that accompany chemotherapy treatments. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Dual melanocortin-4 receptor and GLP-1 receptor agonism amplifies metabolic benefits in diet-induced obese mice

    DEFF Research Database (Denmark)

    Clemmensen, Christoffer; Finan, Brian; Fischer, Katrin

    2015-01-01

    We assessed the efficacy of simultaneous agonism at the glucagon-like peptide-1 receptor (GLP-1R) and the melanocortin-4 receptor (MC4R) for the treatment of obesity and diabetes in rodents. Diet-induced obese (DIO) mice were chronically treated with either the long-acting GLP-1R agonist liraglut...

  10. The Aversive Agent Lithium Chloride Suppresses Phasic Dopamine Release Through Central GLP-1 Receptors.

    Science.gov (United States)

    Fortin, Samantha M; Chartoff, Elena H; Roitman, Mitchell F

    2016-02-01

    Unconditioned rewarding stimuli evoke phasic increases in dopamine concentration in the nucleus accumbens (NAc) while discrete aversive stimuli elicit pauses in dopamine neuron firing and reductions in NAc dopamine concentration. The unconditioned effects of more prolonged aversive states on dopamine release dynamics are not well understood and are investigated here using the malaise-inducing agent lithium chloride (LiCl). We used fast-scan cyclic voltammetry to measure phasic increases in NAc dopamine resulting from electrical stimulation of dopamine cell bodies in the ventral tegmental area (VTA). Systemic LiCl injection reduced electrically evoked dopamine release in the NAc of both anesthetized and awake rats. As some behavioral effects of LiCl appear to be mediated through glucagon-like peptide-1 receptor (GLP-1R) activation, we hypothesized that the suppression of phasic dopamine by LiCl is GLP-1R dependent. Indeed, peripheral pretreatment with the GLP-1R antagonist exendin-9 (Ex-9) potently attenuated the LiCl-induced suppression of dopamine. Pretreatment with Ex-9 did not, however, affect the suppression of phasic dopamine release by the kappa-opioid receptor agonist, salvinorin A, supporting a selective effect of GLP-1R stimulation in LiCl-induced dopamine suppression. By delivering Ex-9 to either the lateral or fourth ventricle, we highlight a population of central GLP-1 receptors rostral to the hindbrain that are involved in the LiCl-mediated suppression of NAc dopamine release.

  11. Quantitative Impact of Plasma Clearance and Down-regulation on GLP-1 Receptor Molecular Imaging.

    Science.gov (United States)

    Zhang, Liang; Thurber, Greg M

    2016-02-01

    Quantitative molecular imaging of beta cell mass (BCM) would enable early detection and treatment monitoring of type 1 diabetes. The glucagon-like peptide-1 (GLP-1) receptor is an attractive target due to its beta cell specificity and cell surface location. We quantitatively investigated the impact of plasma clearance and receptor internalization on targeting efficiency in healthy B6 mice. Four exenatide-based probes were synthesized that varied in molecular weight, binding affinity, and plasma clearance. The GLP-1 receptor internalization rate and in vivo receptor expression were quantified. Receptor internalization (54,000 receptors/cell in vivo) decreased significantly within minutes, reducing the benefit of a slower-clearing agent. The multimers and albumin binding probes had higher kidney and liver uptake, respectively. Slow plasma clearance is beneficial for GLP-1 receptor peptide therapeutics. However, for exendin-based imaging of islets, down-regulation of the GLP-1 receptor and non-specific background uptake result in a higher target-to-background ratio for fast-clearing agents.

  12. Recent Advances in GLP-1 Receptor Agonists for Use in Diabetes Mellitus.

    Science.gov (United States)

    McBrayer, Dominic N; Tal-Gan, Yftah

    2017-09-01

    Preclinical Research Mimetics of Glucagon-like peptide 1 (GLP-1) represent a useful alternative or complementary treatment choice to insulin in the treatment of diabetes mellitus. The lack of hypoglycemia as a side effect when GLP-1 receptor agonists are used along with the tendency of these therapeutic agents to prevent or even reduce weight gain makes them valuable targets in therapy development. However, native GLP-1 and many of its early analogues have very short half-lives, requiring repeated treatment to maintain therapeutic levels. As all current treatments are injected subcutaneously, a large focus has been made on trying to extend the half-lives of GLP-1 analogues while retaining bioactivity. Most success in this regard has been achieved with the use of peptide-protein fusions, which are not as well suited for oral administration. However, recent work focused on the development of non-fusion peptides with increased half-lives that may be more appropriate for oral administration. This minireview discusses the structural characteristics of past and present analogues as well as the recent work conducted toward developing novel GLP-1 receptor agonists. Drug Dev Res 78 : 292-299, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  13. Sustained expression of GLP-1 receptor differentially modulates β-cell functions in diabetic and nondiabetic mice

    International Nuclear Information System (INIS)

    Kubo, Fumiyo; Miyatsuka, Takeshi; Sasaki, Shugo; Takahara, Mitsuyoshi; Yamamoto, Yuichi; Shimo, Naoki; Watada, Hirotaka; Kaneto, Hideaki; Gannon, Maureen; Matsuoka, Taka-aki; Shimomura, Iichiro

    2016-01-01

    Glucagon-like peptide 1 (GLP-1) has been shown to play important roles in maintaining β-cell functions, such as insulin secretion and proliferation. While expression levels of GLP-1 receptor (Glp1r) are compromised in the islets of diabetic rodents, it remains unclear when and to what degree Glp1r mRNA levels are decreased during the progression of diabetes. In this study, we performed real-time PCR with the islets of db/db diabetic mice at different ages, and found that the expression levels of Glp1r were comparable to those of the islets of nondiabetic db/misty controls at the age of four weeks, and were significantly decreased at the age of eight and 12 weeks. To investigate whether restored expression of Glp1r affects the diabetic phenotypes, we generated the transgenic mouse model Pdx1"P"B-CreER"T"M; CAG-CAT-Glp1r (βGlp1r) that allows for induction of Glp1r expression specifically in β cells. Whereas the expression of exogenous Glp1r had no measurable effect on glucose tolerance in nondiabetic βGlp1r;db/misty mice, βGlp1r;db/db mice exhibited higher glucose and lower insulin levels in blood on glucose challenge test than control db/db littermates. In contrast, four weeks of treatment with exendin-4 improved the glucose profiles and increased serum insulin levels in βGlp1r;db/db mice, to significantly higher levels than those in control db/db mice. These differential effects of exogenous Glp1r in nondiabetic and diabetic mice suggest that downregulation of Glp1r might be required to slow the progression of β-cell failure under diabetic conditions. - Highlights: • Expression levels of incretin receptors were significantly decreased in diabetic db/db islets after the age of eight weeks. • A transgenic mouse model expressing Glp1r specifically in β cells was generated. • Exogenous expression of Glp1r in β cells did not affect metabolic profiles in nondiabetic mice. • Sustained expression of Glp1r in diabetic db/db β cells deteriorated glucose

  14. Sustained expression of GLP-1 receptor differentially modulates β-cell functions in diabetic and nondiabetic mice

    Energy Technology Data Exchange (ETDEWEB)

    Kubo, Fumiyo [Department of Metabolic Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); Miyatsuka, Takeshi, E-mail: miyatsuka-takeshi@umin.net [Department of Metabolic Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); Department of Medicine, Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421 (Japan); Sasaki, Shugo; Takahara, Mitsuyoshi; Yamamoto, Yuichi; Shimo, Naoki [Department of Metabolic Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); Watada, Hirotaka [Department of Medicine, Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421 (Japan); Kaneto, Hideaki [Department of Diabetes, Endocrinology and Metabolism, Kawasaki Medical School, 577 Matsushima, Kurashiki, Japan Okayama 701-0192 (Japan); Gannon, Maureen [Department of Medicine, Division of Diabetes, Endocrinology, and Metabolism, Vanderbilt University Medical Center, 2220 Pierce Ave. 746 PRB, Nashville, TN 37232-6303 (United States); Matsuoka, Taka-aki; Shimomura, Iichiro [Department of Metabolic Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2016-02-26

    Glucagon-like peptide 1 (GLP-1) has been shown to play important roles in maintaining β-cell functions, such as insulin secretion and proliferation. While expression levels of GLP-1 receptor (Glp1r) are compromised in the islets of diabetic rodents, it remains unclear when and to what degree Glp1r mRNA levels are decreased during the progression of diabetes. In this study, we performed real-time PCR with the islets of db/db diabetic mice at different ages, and found that the expression levels of Glp1r were comparable to those of the islets of nondiabetic db/misty controls at the age of four weeks, and were significantly decreased at the age of eight and 12 weeks. To investigate whether restored expression of Glp1r affects the diabetic phenotypes, we generated the transgenic mouse model Pdx1{sup PB}-CreER{sup TM}; CAG-CAT-Glp1r (βGlp1r) that allows for induction of Glp1r expression specifically in β cells. Whereas the expression of exogenous Glp1r had no measurable effect on glucose tolerance in nondiabetic βGlp1r;db/misty mice, βGlp1r;db/db mice exhibited higher glucose and lower insulin levels in blood on glucose challenge test than control db/db littermates. In contrast, four weeks of treatment with exendin-4 improved the glucose profiles and increased serum insulin levels in βGlp1r;db/db mice, to significantly higher levels than those in control db/db mice. These differential effects of exogenous Glp1r in nondiabetic and diabetic mice suggest that downregulation of Glp1r might be required to slow the progression of β-cell failure under diabetic conditions. - Highlights: • Expression levels of incretin receptors were significantly decreased in diabetic db/db islets after the age of eight weeks. • A transgenic mouse model expressing Glp1r specifically in β cells was generated. • Exogenous expression of Glp1r in β cells did not affect metabolic profiles in nondiabetic mice. • Sustained expression of Glp1r in diabetic db/db β cells deteriorated

  15. Lixisenatide, a novel GLP-1 receptor agonist for the treatment of type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Christensen, Mikkel; Knop, Filip K; Holst, Jens J

    2009-01-01

    Lixisenatide, under development by sanofi-aventis, is a novel human glucagon-like peptide-1 receptor (GLP-1R) agonist for the treatment of type 2 diabetes mellitus (T2DM; non-insulin dependent diabetes). The structure of lixisenatide, based on exendin-4(1-39) modified C-terminally with six Lys...... of the anticipated effects of lixisenatide on glycemic measures and weight; favorable results would place lixisenatide for consideration among other GLP-1R agonists in the treatment armamentarium for T2DM....

  16. Activation of GLP-1 receptors on vascular smooth muscle cells reduces the autoregulatory response in afferent arterioles and increases renal blood flow

    DEFF Research Database (Denmark)

    Jensen, Elisa Pouline; Poulsen, Steen Seier; Kissow, Hannelouise

    2015-01-01

    was to localize renal GLP-1 receptors and describe GLP-1 mediated effects on the renal vasculature. We hypothesized that renal GLP-1 receptors are located in the renal microcirculation and activation of these affects renal autoregulation and increases renal blood flow. In vivo autoradiography using 125I-GLP-1......, 125I-exendin-4 (GLP-1 analog) and 125I-exendin 9-39 (GLP-1 receptor antagonist) was performed in rodents to localize specific GLP-1 receptor binding. GLP-1 mediated effects on blood pressure (BP), renal blood flow (RBF), heart rate (HR), renin secretion, urinary flow rate and Na+ and K+ excretion were...... conclude that GLP-1 receptors are located in the renal vasculature including afferent arterioles. Activation of these receptors reduces the autoregulatory response of afferent arterioles to acute pressure increases and increases renal blood flow in normotensive rats....

  17. Central GLP-1 receptor signalling accelerates plasma clearance of triacylglycerol and glucose by activating brown adipose tissue in mice

    NARCIS (Netherlands)

    Kooijman, Sander; Wang, Yanan; Parlevliet, Edwin T.; Boon, Mariëtte R.; Edelschaap, David; Snaterse, Gido; Pijl, Hanno; Romijn, Johannes A.; Rensen, Patrick C. N.

    2015-01-01

    Glucagon-like peptide 1 (GLP-1) receptor (GLP-1R) agonism, used in the treatment of type 2 diabetes, has recently been shown to increase thermogenesis via the brain. As brown adipose tissue (BAT) produces heat by burning triacylglycerol (TG) and takes up glucose for de novo lipogenesis, the aim of

  18. Emotional eating is associated with increased brain responses to food-cues and reduced sensitivity to GLP-1 receptor activation

    NARCIS (Netherlands)

    van Bloemendaal, L.; Veltman, D.J.; ten Kulve, J.S.; Drent, M.L.; Barkhof, F.; Diamant, M.; IJzerman, R.G.

    2015-01-01

    Objective The neural correlates and pathophysiology of emotional eating are insufficiently known. Glucagon-like peptide-1 (GLP-1), a postprandial hormone, plays a role in feeding behavior by signaling satiety to the brain. GLP-1 receptor agonists, used for treatment of type 2 diabetes (T2DM),

  19. A comparative safety review between GLP-1 receptor agonists and SGLT2 inhibitors for diabetes treatment.

    Science.gov (United States)

    Consoli, Agostino; Formoso, Gloria; Baldassarre, Maria Pompea Antonia; Febo, Fabrizio

    2018-03-01

    Glucagon-like peptide-1 receptor agonists (GLP-1RA) and sodium glucose cotransporter 2 inhibitors (SGLT2i) are of particular interest in type 2 diabetes treatment strategies, due to their efficacy in reducing HbA1c with a low risk of hypoglycaemia, to their positive effects on body weight and blood pressure and in light of their effects on cardiovascular risk and on nephroprotection emerged from the most recent cardiovascular outcome trials. Since it is therefore very likely that GLP-1RA and SGLT2i use will become more and more common, it is more and more important to gather and discuss information about their safety profile. Area Covered: adverse events and the safety concerns most often emerged in trials with GLP-1RA namely, exenatide long acting release (LAR), dulaglutide, liraglutide, semaglutide, lixisenatide or SGLT2i, namely empagliflozin, dapagliflozin, canagliflozin and SGLT2i with an attempt at comparing the safety profiles of molecules of these two classes. Expert opinion: GLP-1RA and SGLT2i, although each associated with different specific side effects, share a 'similar' safety profile and are both drugs relatively easy to handle. The potentially complementary mechanisms of action, the cardio and nephroprotective effects demonstrated by molecules of both classes, make these drugs potentially useful even in add on to each other.

  20. Glucagon-like peptide-1 acutely affects renal blood flow and urinary flow rate in spontaneously hypertensive rats despite significantly reduced renal expression of GLP-1 receptors

    DEFF Research Database (Denmark)

    Ronn, Jonas; Jensen, Elisa P; Wewer Albrechtsen, Nicolai J

    2017-01-01

    to increased mean arterial pressure (MAP) and increased renal blood flow (RBF). In hypertensive animal models, GLP-1 has been reported both to increase and decrease MAP. The aim of this study was to examine expression of renal GLP-1 receptors in spontaneously hypertensive rats (SHR) and to assess the effect......Glucagon-like peptide-1 (GLP-1) is an incretin hormone increasing postprandial insulin release. GLP-1 also induces diuresis and natriuresis in humans and rodents. The GLP-1 receptor is extensively expressed in the renal vascular tree in normotensive rats where acute GLP-1 treatment leads...... in the kidney from SHR. However, acute intrarenal infusion of GLP-1 increased MAP, RBF, dieresis, and natriuresis without affecting heart rate in both rat strains. These results suggest that the acute renal effects of GLP-1 in SHR are caused either by extrarenal GLP-1 receptors activating other mechanisms (e...

  1. Strategies to improve outcome after islet transplantation using the GLP-1 receptor agonist, extendin-4

    OpenAIRE

    Sharma, Amit

    2007-01-01

    Transplantation of pancreatic islets into the liver via the portal vein has emerged as a treatment option for patients with type I diabetes mellitus. However, loss of functional beta cell mass during isolation and following implantation is a major obstacle in obtaining good long-term results. Exendin-4, a glucagonlike peptide-1 (GLP-1) receptor agonist, improves glucose homeostasis in patients with diabetes. It also has anti-apoptotic and beta cell proliferative properties t...

  2. Glucagon-like peptide-1 acutely affects renal blood flow and urinary flow rate in spontaneously hypertensive rats despite significantly reduced renal expression of GLP-1 receptors.

    Science.gov (United States)

    Ronn, Jonas; Jensen, Elisa P; Wewer Albrechtsen, Nicolai J; Holst, Jens Juul; Sorensen, Charlotte M

    2017-12-01

    Glucagon-like peptide-1 (GLP-1) is an incretin hormone increasing postprandial insulin release. GLP-1 also induces diuresis and natriuresis in humans and rodents. The GLP-1 receptor is extensively expressed in the renal vascular tree in normotensive rats where acute GLP-1 treatment leads to increased mean arterial pressure (MAP) and increased renal blood flow (RBF). In hypertensive animal models, GLP-1 has been reported both to increase and decrease MAP. The aim of this study was to examine expression of renal GLP-1 receptors in spontaneously hypertensive rats (SHR) and to assess the effect of acute intrarenal infusion of GLP-1. We hypothesized that GLP-1 would increase diuresis and natriuresis and reduce MAP in SHR. Immunohistochemical staining and in situ hybridization for the GLP-1 receptor were used to localize GLP-1 receptors in the kidney. Sevoflurane-anesthetized normotensive Sprague-Dawley rats and SHR received a 20 min intrarenal infusion of GLP-1 and changes in MAP, RBF, heart rate, dieresis, and natriuresis were measured. The vasodilatory effect of GLP-1 was assessed in isolated interlobar arteries from normo- and hypertensive rats. We found no expression of GLP-1 receptors in the kidney from SHR. However, acute intrarenal infusion of GLP-1 increased MAP, RBF, dieresis, and natriuresis without affecting heart rate in both rat strains. These results suggest that the acute renal effects of GLP-1 in SHR are caused either by extrarenal GLP-1 receptors activating other mechanisms (e.g., insulin) to induce the renal changes observed or possibly by an alternative renal GLP-1 receptor. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  3. GLP-1 receptor antagonist as a potential probe for pancreatic β-cell imaging

    International Nuclear Information System (INIS)

    Mukai, Eri; Toyoda, Kentaro; Kimura, Hiroyuki; Kawashima, Hidekazu; Fujimoto, Hiroyuki; Ueda, Masashi; Temma, Takashi; Hirao, Konomu; Nagakawa, Kenji; Saji, Hideo; Inagaki, Nobuya

    2009-01-01

    We examined exendin(9-39), an antagonist of glucagon-like peptide-1 (GLP-1) receptor (GLP-1R), as a potential probe for imaging of pancreatic β-cells. To evaluate in vitro receptor specificity, binding assay was performed using dispersed mouse islet cells. Binding assay showed competitive inhibition of [ 125 I]BH-exendin(9-39) binding by non-radioactive exendin(9-39). To assess in vivo selectivity, the biodistribution was evaluated by intravenous administration of [ 125 I]BH-exendin(9-39) to mice. Radioactivity of harvested pancreas reached highest levels at 60 and 120 min among organs examined except lung. Pre-administration of excess non-radioactive exendin(9-39) remarkably and specifically blocked the radioactivity of pancreas. After [ 125 I]BH-exendin(9-39) injection into transgenic mice with pancreatic β-cells expressing GFP, fluorescent and radioactive signals of sections of pancreas were evaluated with an image analyzer. Imaging analysis showed that the fluorescent GFP signals and the radioactive signals were correspondingly located. Thus, the GLP-1R antagonist exendin(9-39) may serve as a useful probe for pancreatic β-cell imaging.

  4. GLP-1 receptor agonists in the treatment of polycystic ovary syndrome.

    Science.gov (United States)

    Lamos, Elizabeth Mary; Malek, Rana; Davis, Stephen N

    2017-04-01

    Polycystic ovarian syndrome (PCOS) affects many women of child-bearing age and is characterized by hyperandrogenism, ovulatory and metabolic dysfunction. A primary treatment goal is weight reduction. The weight loss effects of glucagon-like peptide-1 receptor agonists (GLP-1RA), previously demonstrated in diabetic and obese non-diabetic patients, offer a unique opportunity to expand the medical options available to PCOS patients. Areas covered: Available clinical trials of glucagon-like peptide-1 receptor agonist therapy in PCOS were reviewed. Literature was searched from PubMed using appropriate search terms up to November 2016. Expert commentary: The available studies of GLP-1 RA therapy in the treatment of excess body weight in women with PCOS demonstrate that exenatide and liraglutide are effective in weight reduction either as monotherapy or in combination with metformin. A few studies showed that androgens may be modestly decreased and menstrual frequency may be increased. Eating behavior may be improved with liraglutide therapy. Glucose parameters are generally improved. GLP-1RAs were well-tolerated, with nausea being the most significant adverse side effect. Barriers to utilization may be the short duration studies, lack of familiarity of the medication, the route of administration (injection) and the variable outcomes on ovulation and hyperandrogenism.

  5. Effects of glucagon-like peptide-1 (GLP-1) receptor agonists on cardiovascular risk factors

    DEFF Research Database (Denmark)

    Dalsgaard, Niels B; Vilsbøll, Tina; Knop, Filip K

    2018-01-01

    with continuous-acting treatments, while large GLP-1RAs had a reduced effect on body weight compared with small GLP-1RAs. For glycaemic control, short-acting GLP-1RAs had a greater impact on post-prandial glucose levels versus continuous-acting GLP-1RAs, but for fasting plasma glucose levels and HbA1c, continuous...

  6. The autonomic nervous system and cardiac GLP-1 receptors control heart rate in mice

    Directory of Open Access Journals (Sweden)

    Laurie L. Baggio

    2017-11-01

    Conclusions: GLP-1R agonists increase HR through multiple mechanisms, including regulation of autonomic nervous system function, and activation of the atrial GLP-1R. Surprisingly, the isolated atrial GLP-1R does not transduce a direct chronotropic effect following exposure to GLP-1R agonists in the intact heart, or isolated atrium, ex vivo. Hence, cardiac GLP-1R circuits controlling HR require neural inputs and do not function in a heart-autonomous manner.

  7. Lateral hypothalamic GLP-1 receptors are critical for the control of food reinforcement, ingestive behavior and body weight.

    Science.gov (United States)

    López-Ferreras, L; Richard, J E; Noble, E E; Eerola, K; Anderberg, R H; Olandersson, K; Taing, L; Kanoski, S E; Hayes, M R; Skibicka, K P

    2017-09-12

    Increased motivation for highly rewarding food is a major contributing factor to obesity. Most of the literature focuses on the mesolimbic nuclei as the core of reward behavior regulation. However, the lateral hypothalamus (LH) is also a key reward-control locus in the brain. Here we hypothesize that manipulating glucagon-like peptide-1 receptor (GLP-1R) activity selectively in the LH can profoundly affect food reward behavior, ultimately leading to obesity. Progressive ratio operant responding for sucrose was examined in male and female rats, following GLP-1R activation and pharmacological or genetic GLP-1R blockade in the LH. Ingestive behavior and metabolic parameters, as well as molecular and efferent targets, of the LH GLP-1R activation were also evaluated. Food motivation was reduced by activation of LH GLP-1R. Conversely, acute pharmacological blockade of LH GLP-1R increased food motivation but only in male rats. GLP-1R activation also induced a robust reduction in food intake and body weight. Chronic knockdown of LH GLP-1R induced by intraparenchymal delivery of an adeno-associated virus-short hairpin RNA construct was sufficient to markedly and persistently elevate ingestive behavior and body weight and ultimately resulted in a doubling of fat mass in males and females. Interestingly, increased food reinforcement was again found only in males. Our data identify the LH GLP-1R as an indispensable element of normal food reinforcement, food intake and body weight regulation. These findings also show, for we believe the first time, that brain GLP-1R manipulation can result in a robust and chronic body weight gain. The broader implications of these findings are that the LH differs between females and males in its ability to control motivated and ingestive behaviors.Molecular Psychiatry advance online publication, 12 September 2017; doi:10.1038/mp.2017.187.

  8. Bile Acids Trigger GLP-1 Release Predominantly by Accessing Basolaterally Located G Protein-Coupled Bile Acid Receptors

    DEFF Research Database (Denmark)

    Brighton, Cheryl A.; Rievaj, Juraj; Kuhre, Rune E.

    2015-01-01

    Bile acids are well-recognized stimuli of glucagon-like peptide-1 (GLP-1) secretion. This action has been attributed to activation of the G protein-coupled bile acid receptor GPBAR1 (TGR5), although other potential bile acid sensors include the nuclear farnesoid receptor and the apical sodium......-coupled bile acid transporter ASBT. The aim of this study was to identify pathways important for GLP-1 release and to determine whether bile acids target their receptors on GLP-1-secreting L-cells from the apical or basolateral compartment. Using transgenic mice expressing fluorescent sensors specifically in L...... to either TLCA or TDCA. We conclude that the action of bile acids on GLP-1 secretion is predominantly mediated by GPBAR1 located on the basolateral L-cell membrane, suggesting that stimulation of gut hormone secretion may include postabsorptive mechanisms....

  9. Activation of GLP-1 receptors on vascular smooth muscle cells reduces the autoregulatory response in afferent arterioles and increases renal blood flow.

    Science.gov (United States)

    Jensen, Elisa P; Poulsen, Steen S; Kissow, Hannelouise; Holstein-Rathlou, Niels-Henrik; Deacon, Carolyn F; Jensen, Boye L; Holst, Jens J; Sorensen, Charlotte M

    2015-04-15

    Glucagon-like peptide (GLP)-1 has a range of extrapancreatic effects, including renal effects. The mechanisms are poorly understood, but GLP-1 receptors have been identified in the kidney. However, the exact cellular localization of the renal receptors is poorly described. The aim of the present study was to localize renal GLP-1 receptors and describe GLP-1-mediated effects on the renal vasculature. We hypothesized that renal GLP-1 receptors are located in the renal microcirculation and that activation of these affects renal autoregulation and increases renal blood flow. In vivo autoradiography using (125)I-labeled GLP-1, (125)I-labeled exendin-4 (GLP-1 analog), and (125)I-labeled exendin 9-39 (GLP-1 receptor antagonist) was performed in rodents to localize specific GLP-1 receptor binding. GLP-1-mediated effects on blood pressure, renal blood flow (RBF), heart rate, renin secretion, urinary flow rate, and Na(+) and K(+) excretion were investigated in anesthetized rats. Effects of GLP-1 on afferent arterioles were investigated in isolated mouse kidneys. Specific binding of (125)I-labeled GLP-1, (125)I-labeled exendin-4, and (125)I-labeled exendin 9-39 was observed in the renal vasculature, including afferent arterioles. Infusion of GLP-1 increased blood pressure, RBF, and urinary flow rate significantly in rats. Heart rate and plasma renin concentrations were unchanged. Exendin 9-39 inhibited the increase in RBF. In isolated murine kidneys, GLP-1 and exendin-4 significantly reduced the autoregulatory response of afferent arterioles in response to stepwise increases in pressure. We conclude that GLP-1 receptors are located in the renal vasculature, including afferent arterioles. Activation of these receptors reduces the autoregulatory response of afferent arterioles to acute pressure increases and increases RBF in normotensive rats. Copyright © 2015 the American Physiological Society.

  10. Glucagon-Like Peptide-1 (GLP-1) Receptor Agonists in the Treatment of Obese Women with Polycystic Ovary Syndrome.

    Science.gov (United States)

    Tzotzas, Themistoklis; Karras, Spyridon N; Katsiki, Niki

    2017-01-01

    Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in females and is often associated with a number of cardiometabolic disorders such as central obesity, dyslipidaemia, hypertension, insulin resistance, hyperinsulinaemia, glucose intolerance and type 2 diabetes mellitus (T2DM). Glucagon-like peptide-1 (GLP-1), a gut hormone secreted after a meal, enhances glucosestimulated insulin secretion and additionally suppresses appetite and gastric motility. Most studies found impaired GLP-1 kinetics in obese individuals, whereas small studies in PCOS reported reduced, normal or even elevated GLP-1 levels. Apart from their efficacy in patients with T2DM, some GLP-1 receptor agonists (GLP-1 RAs) have been successfully tested in terms of both efficiency and safety in obese individuals without diabetes and liraglutide 3 mg once daily has been approved as an antiobesity drug in the USA and the European Union. Recently, some small trials of short duration using GLP-1 RAs as monotherapy or combined with metformin in obese PCOS women showed positive results regarding weight reduction and a decrease in testosterone levels but without significant effects on insulin levels, insulin sensitivity and menstrual patterns. Longer term studies with more patients and higher doses of liraglutide (as this drug is already approved for obese individuals) are required to determine the precise indications of GLP-1 RAs in PCOS and to evaluate safety issues. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  11. Robust GLP-1 secretion by basic L-amino acids does not require the GPRC6A receptor

    DEFF Research Database (Denmark)

    Clemmensen, Christoffer; Jørgensen, Christinna V; Smajilovic, Sanela

    2017-01-01

    (GLP-1) secretion is unclear. Therefore, to probe if the GPRC6A receptor is indispensible for amino acid-induced secretion of GLP-1, we treated, with oral gavage, GPRC6A knock-out (KO) and wild-type (WT) littermate mice with GPRC6A ligands: L-arginine and L-ornithine, and assessed GLP-1 levels...... in circulation. We found that oral administration of both L-arginine and L-ornithine significantly increased total plasma GLP-1 levels to a similar level in GPRC6A KO and WT mice 15 minutes after gavage (both amino acids) and accumulated up to 60 minutes after gavage (L-arginine). Conversely, GLP-1 secretion...... at the 30 and 60 minute time points in the KO mice were attenuated and did not reach statistical significance. In summary, these data confirm that L-arginine is a potent GLP-1 secretagogue and show that the main effect occurs independently of GPRC6A. In addition, this is the first study to show that also L...

  12. Activation of the GLP-1 receptors in the nucleus of the solitary tract reduces food reward behavior and targets the mesolimbic system.

    Directory of Open Access Journals (Sweden)

    Jennifer E Richard

    Full Text Available The gut/brain peptide, glucagon like peptide 1 (GLP-1, suppresses food intake by acting on receptors located in key energy balance regulating CNS areas, the hypothalamus or the hindbrain. Moreover, GLP-1 can reduce reward derived from food and motivation to obtain food by acting on its mesolimbic receptors. Together these data suggest a neuroanatomical segregation between homeostatic and reward effects of GLP-1. Here we aim to challenge this view and hypothesize that GLP-1 can regulate food reward behavior by acting directly on the hindbrain, the nucleus of the solitary tract (NTS, GLP-1 receptors (GLP-1R. Using two models of food reward, sucrose progressive ratio operant conditioning and conditioned place preference for food in rats, we show that intra-NTS microinjections of GLP-1 or Exendin-4, a stable analogue of GLP-1, inhibit food reward behavior. When the rats were given a choice between palatable food and chow, intra-NTS Exendin-4 treatment preferentially reduced intake of palatable food but not chow. However, chow intake and body weight were reduced by the NTS GLP-1R activation if chow was offered alone. The NTS GLP-1 activation did not alter general locomotor activity and did not induce nausea, measured by PICA. We further show that GLP-1 fibers are in close apposition to the NTS noradrenergic neurons, which were previously shown to provide a monosynaptic connection between the NTS and the mesolimbic system. Central GLP-1R activation also increased NTS expression of dopamine-β-hydroxylase, a key enzyme in noradrenaline synthesis, indicating a biological link between these two systems. Moreover, NTS GLP-1R activation altered the expression of dopamine-related genes in the ventral tegmental area. These data reveal a food reward-suppressing role of the NTS GLP-1R and indicate that the neurobiological targets underlying food reward control are not limited to the mesolimbic system, instead they are distributed throughout the CNS.

  13. Activation of the GLP-1 receptors in the nucleus of the solitary tract reduces food reward behavior and targets the mesolimbic system.

    Science.gov (United States)

    Richard, Jennifer E; Anderberg, Rozita H; Göteson, Andreas; Gribble, Fiona M; Reimann, Frank; Skibicka, Karolina P

    2015-01-01

    The gut/brain peptide, glucagon like peptide 1 (GLP-1), suppresses food intake by acting on receptors located in key energy balance regulating CNS areas, the hypothalamus or the hindbrain. Moreover, GLP-1 can reduce reward derived from food and motivation to obtain food by acting on its mesolimbic receptors. Together these data suggest a neuroanatomical segregation between homeostatic and reward effects of GLP-1. Here we aim to challenge this view and hypothesize that GLP-1 can regulate food reward behavior by acting directly on the hindbrain, the nucleus of the solitary tract (NTS), GLP-1 receptors (GLP-1R). Using two models of food reward, sucrose progressive ratio operant conditioning and conditioned place preference for food in rats, we show that intra-NTS microinjections of GLP-1 or Exendin-4, a stable analogue of GLP-1, inhibit food reward behavior. When the rats were given a choice between palatable food and chow, intra-NTS Exendin-4 treatment preferentially reduced intake of palatable food but not chow. However, chow intake and body weight were reduced by the NTS GLP-1R activation if chow was offered alone. The NTS GLP-1 activation did not alter general locomotor activity and did not induce nausea, measured by PICA. We further show that GLP-1 fibers are in close apposition to the NTS noradrenergic neurons, which were previously shown to provide a monosynaptic connection between the NTS and the mesolimbic system. Central GLP-1R activation also increased NTS expression of dopamine-β-hydroxylase, a key enzyme in noradrenaline synthesis, indicating a biological link between these two systems. Moreover, NTS GLP-1R activation altered the expression of dopamine-related genes in the ventral tegmental area. These data reveal a food reward-suppressing role of the NTS GLP-1R and indicate that the neurobiological targets underlying food reward control are not limited to the mesolimbic system, instead they are distributed throughout the CNS.

  14. New screening strategy and analysis for identification of allosteric modulators for glucagon-like peptide-1 receptor using GLP-1 (9-36) amide.

    Science.gov (United States)

    Nakane, Atsushi; Gotoh, Yusuke; Ichihara, Junji; Nagata, Hidetaka

    2015-12-15

    The glucagon-like peptide-1 receptor (GLP-1R) is an important physiologic regulator of insulin secretion and a major therapeutic target for diabetes mellitus. GLP-1 (7-36) amide (active form of GLP-1) is truncated to GLP-1 (9-36) amide, which has been described as a weak agonist of GLP-1R and the major form of GLP-1 in the circulation. New classes of positive allosteric modulators (PAMs) for GLP-1R may offer improved therapeutic profiles. To identify these new classes, we developed novel and robust primary and secondary high-throughput screening (HTS) systems in which PAMs were identified to enhance the GLP-1R signaling induced by GLP-1 (9-36) amide. Screening enabled identification of two compounds, HIT-465 and HIT-736, which possessed new patterns of modulation of GLP-1R. We investigated the ability of these compounds to modify GLP-1R signaling enhanced GLP-1 (9-36) amide- and/or GLP-1 (7-36) amide-mediated cyclic adenosine monophosphate (cAMP) accumulation. These compounds also had unique profiles with regard to allosteric modulation of multiple downstream signaling (PathHunter β-arrestin signaling, PathHunter internalization signaling, microscopy-based internalization assay). We found allosteric modulation patterns to be obviously different among HIT-465, HIT-736, and Novo Nordisk compound 2. This work may enable the design of new classes of drug candidates by targeting modulation of GLP-1 (7-36) amide and GLP-1 (9-36) amide. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Qing-Hua Granule induces GLP-1 secretion via bitter taste receptor in db/db mice.

    Science.gov (United States)

    Li, Junyan; Xu, Jie; Hou, Ruifang; Jin, Xin; Wang, Jingyi; Yang, Na; Yang, Li; Liu, Li; Tao, Feng; Lu, Hao

    2017-05-01

    Qing-Hua Granule (QHG), the modified formulation of a classical Chinese prescription named Gegen Qinlian Decoction, was clinically employed to treat type 2 diabetes mellitus (T2DM) through regulation of glucagon-like peptide-1 (GLP-1). However, the potential mechanism is unknown. We investigate whether QHG induces GLP-1 secretion via activation of bitter taste receptor (TAS2R) pathway in the gastrointestinal tract of db/db mice. The db/db mice were intragastrically (i.g.) administered QHG (low/medium/high dose) once daily for 8 weeks. GLP-1 secretion was evaluated. The bitter receptor signaling pathway, which regulates GLP-1 secretion, including TAS2R5 (a subtype of TAS2R), α-gustducin (Gαgust), 1-phosphatidylinositol-4, 5-bisphosphate phosphodiesterase beta-2 (PLCβ2), transient receptor potential cation channel subfamily M member 5 (TRPM5), was assessed by quantitative real-time polymerase chain reaction (qRT-PCR), Western blot and immunohistochemistry (IHC). The biochemical observations of ileum and pancreas tissue were detected histopathologically. Acquity Ultra Performance LCTM - Micromass ZQ 2000 (UPLC-MS) was used for the phytochemical analysis. QHG exhibited significant and dose-dependent effect on GLP-1 secretion in db/db mice, along with significant up-regulation of TAS2R5 mRNA level and activation of TAS2R pathway (p<0.05). In addition, QHG improved the histopathological structure of ileum and pancreatic tissue. Seventeen compounds were identified in QHG. In conclusion, QHG induces GLP-1 secretion in db/db mice, most likely through the bitter taste receptor pathway. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  16. Central GLP-1 receptor activation modulates cocaine-evoked phasic dopamine signaling in the nucleus accumbens core.

    Science.gov (United States)

    Fortin, Samantha M; Roitman, Mitchell F

    2017-07-01

    Drugs of abuse increase the frequency and magnitude of brief (1-3s), high concentration (phasic) dopamine release events in terminal regions. These are thought to be a critical part of drug reinforcement and ultimately the development of addiction. Recently, metabolic regulatory peptides, including the satiety signal glucagon-like peptide-1 (GLP-1), have been shown to modulate cocaine reward-driven behavior and sustained dopamine levels after cocaine administration. Here, we use fast-scan cyclic voltammetry (FSCV) to explore GLP-1 receptor (GLP-1R) modulation of dynamic dopamine release in the nucleus accumbens (NAc) during cocaine administration. We analyzed dopamine release events in both the NAc shell and core, as these two subregions are differentially affected by cocaine and uniquely contribute to motivated behavior. We found that central delivery of the GLP-1R agonist Exendin-4 suppressed the induction of phasic dopamine release events by intravenous cocaine. This effect was selective for dopamine signaling in the NAc core. Suppression of phasic signaling in the core by Exendin-4 could not be attributed to interference with cocaine binding to one of its major substrates, the dopamine transporter, as cocaine-induced increases in reuptake were unaffected. The results suggest that GLP-1R activation, instead, exerts its suppressive effects by altering dopamine release - possibly by suppressing the excitability of dopamine neurons. Given the role of NAc core dopamine in the generation of conditioned responses based on associative learning, suppression of cocaine-induced dopamine signaling in this subregion by GLP-1R agonism may decrease the reinforcing properties of cocaine. Thus, GLP-1Rs remain viable targets for the treatment and prevention of cocaine seeking, taking and relapse. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Pancreatic effects of GLP-1

    DEFF Research Database (Denmark)

    Kuhre, Rune Ehrenreich; Albrechtsen, Nicolai Jacob Wewer; Holst, Jens Juul

    2014-01-01

    -dependent manner. But perhaps equally importantly, GLP-1’s glucose lowering effects are attributable to a strong inhibition of glucagon secretion, and, thereby, a reduction of hepatic glucose output. The effects of GLP-1 on insulin secretion are mediated by binding of the hormone to the receptor (GLP-1r......) on the pancreatic β-cell, which increases intracellular cAMP levels and sets in motion a plethora of events that lead to secretion. In contrast, the inhibitory effect of GLP-1 on the α-cell may be indirect, involving paracrine intra-islet regulation by somatostatin and possibly also insulin, although GLP-1 also...... inhibits glucagon secretion in patients with type 1 diabetes mellitus. Besides these acute effects on the endocrine pancreas, GLP-1 also appears to have a positive effect on β-cell mass. In the following we will review GLP-1’s pancreatic effects with particular focus on its effects on pancreatic islets...

  18. Does a GLP-1 receptor agonist change glucose tolerance in patients treated with antipsychotic medications?

    DEFF Research Database (Denmark)

    Larsen, Julie Rask; Vedtofte, Louise; Holst, Jens Juul

    2014-01-01

    . Additionally, patients with schizophrenia-spectrum disorders not infrequently consume alcohol. Glucagon-like peptide-1 (GLP-1) has shown to improve glycaemic control and reduce alcohol intake among patients with type 2 diabetes. OBJECTIVES: To investigate whether the beneficial effects of GLP-1 analogues...

  19. Sweet Taste Receptor Activation in the Gut Is of Limited Importance for Glucose-Stimulated GLP-1 and GIP Secretion

    DEFF Research Database (Denmark)

    Saltiel, Monika Yosifova; Kuhre, Rune Ehrenreich; Christiansen, Charlotte Bayer

    2017-01-01

    Glucose stimulates the secretion of the incretin hormones: glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP). It is debated whether the sweet taste receptor (STR) triggers this secretion. We investigated the role of STR activation for glucose-stimulated incretin...

  20. Effects of microwave exposure on glucagon-like peptide-1 (GLP-1) and its receptor and the relationship with learning and memory injury

    International Nuclear Information System (INIS)

    Zhang Lei; Zhou Zhou; Zhang Guangbin; Yu Zhengping

    2007-01-01

    In order to explore the effects of microwave exposure on GLP-1 and its receptor, the relationship between the changes of GLP-1 and its receptor and learning and memory injury induced by microwave exposure has been studied in this paper. Morris water maze was used to evaluate learning and memory ability of rats. The changes of the plasma GLP-1 level were measured by ELISA assay. Alteration of the GLP-1R mRNA expression in rat hippocampus was determined by RT-PCR and Apoptosis was detected by TUNEL. Our study showed that microwave exposure injured the learning and memory abilities of rats meanwhile plasma GLP-1 level was decreased and GLP-1R expression in hippocampus was down-regulated, which can be protected by pretreatment with GLP-1. Alterations in GLP-1 and GLP-1R are, at least partially, responsible for the microwave exposure induced learning and memory dysfunction and neuronal injury. These data provide some new clues to investigate the mechanisms of microwave exposure induced neuronal injury and develop clinical approaches for treatment of microwave exposure induced injury. It can provide some new ideals for investigation of related mechanism and development of clinical treatment under exposed microwave irradiation. (authors)

  1. Quantification of the contribution of GLP-1 to mediating insulinotropic effects of DPP-4 inhibition with vildagliptin in healthy subjects and type 2-diabetic patients using exendin [9-39] as a GLP-1 receptor antagonist

    DEFF Research Database (Denmark)

    Nauck, Michael A; Kind, J; Köthe, Lars D

    2016-01-01

    We quantified the contribution of GLP-1 as a mediator of the therapeutic effects of dipeptidyl peptidase 4 (DPP-4) inhibition (vildagliptin) by using the GLP-1 receptor antagonist exendin [9-39] in patients with type 2 diabetes and in healthy subjects. Thirty-two patients with type 2 diabetes...... and 29 age-and weight-matched healthy control subjects were treated in randomized order with 100 mg once daily vildagliptin or placebo for 10 days. Meal tests were performed (days 9 and 10) without and with a high-dose intravenous infusion of exendin [9-39]. The main end point was the ratio of the areas...... under the curve (AUCs) of integrated insulin secretion rates (total AUC(ISR)) and glucose (total AUC(glucose)) over 4 h after the meal. Vildagliptin treatment more than doubled responses of intact GLP-1 and glucose-dependent insulinotropic polypeptide and lowered glucose responses without changing AUC...

  2. Centrally located GLP-1 receptors modulate gastric slow waves and cardiovascular function in ferrets consistent with the induction of nausea.

    Science.gov (United States)

    Lu, Zengbing; Yeung, Chi-Kong; Lin, Ge; Yew, David T W; Andrews, P L R; Rudd, John A

    2017-10-01

    Glucagon-like peptide-1 (GLP-1) receptor agonists are indicated for the treatment of Type 2 diabetes and obesity, but can cause nausea and emesis in some patients. GLP-1 receptors are distributed widely in the brain, where they contribute to mechanisms of emesis, reduced appetite and aversion, but it is not known if these centrally located receptors also contribute to a modulation of gastric slow wave activity, which is linked causally to nausea. Our aim was to investigate the potential of the GLP-1 receptor agonist, exendin-4, administered into the 3rd ventricle to modulate emesis, feeding and gastric slow wave activity. Thermoregulation and cardiovascular parameters were also monitored, as they are disturbed during nausea. Ferrets were used as common laboratory rodents do not have an emetic reflex. A guide cannula was implanted into the 3rd ventricle for delivering a previously established dose of exendin-4 (10nmol), which had been shown to induce emesis and behaviours indicative of 'nausea'. Radiotelemetry recorded gastric myoelectric activity (GMA; slow waves), blood pressure and heart rate variability (HRV), and core temperature; food intake and behaviour were also assessed. Exendin-4 (10nmol, i.c.v.) decreased the dominant frequency of GMA, with an associated increase in the percentage of bradygastric power (lasting ~4h). Food intake was inhibited in all animals, with 63% exhibiting emesis. Exendin-4 also increased blood pressure (lasting ~24h) and heart rate (lasting ~7h), decreased HRV (lasting ~24h), and caused transient hyperthermia. None of the above parameters were emesis-dependent. The present study shows for the first time that gastric slow waves may be modulated by GLP-1 receptors in the brain through mechanisms that appear independent from emesis. Taken together with a reduction in HRV, the findings are consistent with changes associated with the occurrence of nausea in humans. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Effect of GLP-1 Receptor Agonist Treatment on Body weight in Obese Antipsychotic-treated Patients with Schizophrenia

    DEFF Research Database (Denmark)

    Ishøy, Pelle L; Knop, Filip K; Broberg, Brian V

    2017-01-01

    AIMS: Schizophrenia is associated with cardiovascular co-morbidity and a reduced life-expectancy of up to 20 years. Antipsychotics are dopamine D2 receptor antagonists and the standard of medical care in schizophrenia, but the drugs are associated with severe metabolic side effects like obesity...... and diabetes. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are registered for treatment of both obesity and type 2 diabetes. We investigated metabolic effects of the GLP-1RA, exenatide once-weekly, in non-diabetic, antipsychotic-treated, obese patients with schizophrenia. MATERIAL AND METHODS......: Antipsychotic-treated, obese, non-diabetic, schizophrenia spectrum patients were randomized to double-blinded adjunctive treatment with once-weekly subcutaneous exenatide (n = 23) or placebo (n = 22) injections for three months. The primary outcome was body weight loss after treatment and repeated measures...

  4. Liraglutide Versus Lixisenatide: Long-Term Cost-Effectiveness of GLP-1 Receptor Agonist Therapy for the Treatment of Type 2 Diabetes in Spain

    OpenAIRE

    Mezquita-Raya, Pedro; Ram?rez de Arellano, Antonio; Kragh, Nana; Vega-Hernandez, Gabriela; P?hlmann, Johannes; Valentine, William J.; Hunt, Barnaby

    2017-01-01

    Introduction Glucagon-like peptide-1 (GLP-1) receptor agonists are used successfully in the treatment of patients with type 2 diabetes as they are associated with low hypoglycemia rates, weight loss and improved glycemic control. This study compared, in the Spanish setting, the cost-effectiveness of liraglutide 1.8?mg versus lixisenatide 20??g, both GLP-1 receptor agonists, for patients with type 2 diabetes who had not achieved glycemic control targets on metformin monotherapy. Methods The IM...

  5. Liraglutide, a GLP-1 Receptor Agonist, Which Decreases Hypothalamic 5-HT2A Receptor Expression, Reduces Appetite and Body Weight Independently of Serotonin Synthesis in Mice

    Directory of Open Access Journals (Sweden)

    Katsunori Nonogaki

    2018-01-01

    Full Text Available A recent report suggested that brain-derived serotonin (5-HT is critical for maintaining weight loss induced by glucagon-like peptide-1 (GLP-1 receptor activation in rats and that 5-HT2A receptors mediate the feeding suppression and weight loss induced by GLP-1 receptor activation. Here, we show that changes in daily food intake and body weight induced by intraperitoneal administration of liraglutide, a GLP-1 receptor agonist, over 4 days did not differ between mice treated with the tryptophan hydroxylase (Tph inhibitor p-chlorophenylalanine (PCPA for 3 days and mice without PCPA treatment. Treatment with PCPA did not affect hypothalamic 5-HT2A receptor expression. Despite the anorexic effect of liraglutide disappearing after the first day of treatment, the body weight loss induced by liraglutide persisted for 4 days in mice treated with or without PCPA. Intraperitoneal administration of liraglutide significantly decreased the gene expression of hypothalamic 5-HT2A receptors 1 h after injection. Moreover, the acute anorexic effects of liraglutide were blunted in mice treated with the high-affinity 5-HT2A agonist (4-bromo-3,6-dimethoxybenzocyclobuten-1-yl methylamine hydrobromide 14 h or 24 h before liraglutide injection. These findings suggest that liraglutide reduces appetite and body weight independently of 5-HT synthesis in mice, whereas GLP-1 receptor activation downregulates the gene expression of hypothalamic 5-HT2A receptors.

  6. Estudio del dominio carboxi-terminal del receptor de GLP-1(7-36) amida

    OpenAIRE

    Vázquez Pérez, Patricia

    2002-01-01

    El péptido relacionado con el glucagón de tipo 1 (GLP-1), está implicado en muchas funciones biológicas, como son el aumento de al secreción de insulina dependiente de glucosa, así como la estimación de la presión arterial y producción de surfactante pulmonar. A nivel central el GLP-1(7-36)amida estimula la liberación selectiva de neurotransmisores y participa en la regulación de procesos tales como la ingesta de alimentos y agua, la temperatura corporal y el control de ciertas funciones card...

  7. Brain GLP-1 and insulin sensitivity.

    Science.gov (United States)

    Sandoval, Darleen; Sisley, Stephanie R

    2015-12-15

    Type 2 diabetes is often treated with a class of drugs referred to as glucagon-like peptide-1 (GLP-1) analogs. GLP-1 is a peptide secreted by the gut that acts through only one known receptor, the GLP-1 receptor. The primary function of GLP-1 is thought to be lowering of postprandial glucose levels. Indeed, medications utilizing this system, including the long-acting GLP-1 analogs liraglutide and exenatide, are beneficial in reducing both blood sugars and body weight. GLP-1 analogs were long presumed to affect glucose control through their ability to increase insulin levels through peripheral action on beta cells. However, multiple lines of data point to the ability of GLP-1 to act within the brain to alter glucose regulation. In this review we will discuss the evidence for a central GLP-1 system and the effects of GLP-1 in the brain on regulating multiple facets of glucose homeostasis including glucose tolerance, insulin production, insulin sensitivity, hepatic glucose production, muscle glucose uptake, and connections of the central GLP-1 system to the gut. Although the evidence indicates that GLP-1 receptors in the brain are not necessary for physiologic control of glucose regulation, we discuss the research showing a strong effect of acute manipulation of the central GLP-1 system on glucose control and how it is relevant to type 2 diabetic patients. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  8. Direct control of peripheral lipid deposition by CNS GLP-1 receptor signaling is mediated by the sympathetic nervous system and blunted in diet-induced obesity.

    Science.gov (United States)

    Nogueiras, Ruben; Pérez-Tilve, Diego; Veyrat-Durebex, Christelle; Morgan, Donald A; Varela, Luis; Haynes, William G; Patterson, James T; Disse, Emmanuel; Pfluger, Paul T; López, Miguel; Woods, Stephen C; DiMarchi, Richard; Diéguez, Carlos; Rahmouni, Kamal; Rohner-Jeanrenaud, Françoise; Tschöp, Matthias H

    2009-05-06

    We investigated a possible role of the central glucagon-like peptide (GLP-1) receptor system as an essential brain circuit regulating adiposity through effects on nutrient partitioning and lipid metabolism independent from feeding behavior. Both lean and diet-induced obesity mice were used for our experiments. GLP-1 (7-36) amide was infused in the brain for 2 or 7 d. The expression of key enzymes involved in lipid metabolism was measured by real-time PCR or Western blot. To test the hypothesis that the sympathetic nervous system may be responsible for informing adipocytes about changes in CNS GLP-1 tone, we have performed direct recording of sympathetic nerve activity combined with experiments in genetically manipulated mice lacking beta-adrenergic receptors. Intracerebroventricular infusion of GLP-1 in mice directly and potently decreases lipid storage in white adipose tissue. These effects are independent from nutrient intake. Such CNS control of adipocyte metabolism was found to depend partially on a functional sympathetic nervous system. Furthermore, the effects of CNS GLP-1 on adipocyte metabolism were blunted in diet-induced obese mice. The CNS GLP-1 system decreases fat storage via direct modulation of adipocyte metabolism. This CNS GLP-1 control of adipocyte lipid metabolism appears to be mediated at least in part by the sympathetic nervous system and is independent of parallel changes in food intake and body weight. Importantly, the CNS GLP-1 system loses the capacity to modulate adipocyte metabolism in obese states, suggesting an obesity-induced adipocyte resistance to CNS GLP-1.

  9. Treatment of type 2 diabetes mellitus with agonists of the GLP-1 receptor or DPP-IV inhibitors

    DEFF Research Database (Denmark)

    Holst, Jens Juul

    2004-01-01

    in the treatment of Type 2 diabetes, causing marked improvements in glycaemic profile, insulin sensitivity and beta-cell performance, as well as weight reduction. The hormone is metabolised rapidly by the enzyme dipeptidyl peptidase IV (DPP-IV) and, therefore, cannot be easily used clinically. Instead, resistant...... with exendin have been carried out for > 6 months and have indicated efficacy in patients inadequately treated with oral antidiabetic agents. Orally active DPP-IV inhibitors, suitable for once-daily administration, have demonstrated similar efficacy. Diabetes therapy, based on GLP-1 receptor activation...

  10. The GLP-1 Receptor Agonist Exendin-4 and Diazepam Differentially Regulate GABAA Receptor-Mediated Tonic Currents in Rat Hippocampal CA3 Pyramidal Neurons.

    Directory of Open Access Journals (Sweden)

    Sergiy V Korol

    Full Text Available Glucagon-like peptide-1 (GLP-1 is a metabolic hormone that is secreted in a glucose-dependent manner and enhances insulin secretion. GLP-1 receptors are also found in the brain where their signalling affects neuronal activity. We have previously shown that the GLP-1 receptor agonists, GLP-1 and exendin-4 enhanced GABA-activated synaptic and tonic currents in rat hippocampal CA3 pyramidal neurons. The hippocampus is the centre for memory and learning and is important for cognition. Here we examined if exendin-4 similarly enhanced the GABA-activated currents in the presence of the benzodiazepine diazepam. In whole-cell recordings in rat brain slices, diazepam (1 μM, an allosteric positive modulator of GABAA receptors, alone enhanced the spontaneous inhibitory postsynaptic current (sIPSC amplitude and frequency by a factor of 1.3 and 1.6, respectively, and doubled the tonic GABAA current normally recorded in the CA3 pyramidal cells. Importantly, in the presence of exendin-4 (10 nM plus diazepam (1 μM, only the tonic but not the sIPSC currents transiently increased as compared to currents recorded in the presence of diazepam alone. The results suggest that exendin-4 potentiates a subpopulation of extrasynaptic GABAA receptors in the CA3 pyramidal neurons.

  11. Effect of GLP-1 receptor agonist treatment on body weight in obese antipsychotic-treated patients with schizophrenia

    DEFF Research Database (Denmark)

    Ishøy, Pelle L; Knop, Filip K; Broberg, Brian V

    2017-01-01

    and placebo groups experienced significant ( P  = .004), however similar ( P  = .98), weight losses of 2.24 ± 3.3 and 2.23 ± 4.4 kg, respectively, after 3 months of treatment. CONCLUSIONS: Treatment with exenatide once-weekly did not promote weight loss in obese, antipsychotic-treated patients......AIMS: Schizophrenia is associated with cardiovascular co-morbidity and a reduced life-expectancy of up to 20 years. Antipsychotics are dopamine D2 receptor antagonists and are the standard of medical care in schizophrenia, but the drugs are associated with severe metabolic side effects...... such as obesity and diabetes. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are registered for treatment of both obesity and type 2 diabetes. We investigated metabolic effects of the GLP-1RA, exenatide once-weekly, in non-diabetic, antipsychotic-treated, obese patients with schizophrenia. MATERIAL...

  12. No cognitive-enhancing effect of GLP-1 receptor agonism in antipsychotic-treated, obese patients with schizophrenia.

    Science.gov (United States)

    Ishøy, P L; Fagerlund, B; Broberg, B V; Bak, N; Knop, F K; Glenthøj, B Y; Ebdrup, B H

    2017-07-01

    Schizophrenia is associated with profound cognitive and psychosocial impairments. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are used for diabetes and obesity treatment, and animal studies have indicated cognitive-enhancing effects. In this investigator-initiated, double-blind, randomized, placebo-controlled trial, we tested non-metabolic effects of exenatide once-weekly (Bydureon™) in obese, antipsychotic-treated patients with schizohrenia spectrum disorder. Before and after 3 months of exenatide (N = 20) or placebo (N = 20) treatment, patients were assessed with the following: Brief Assessment of Cognition in Schizophrenia (BACS), Rey-Osterreith complex figure test (REY), Short-Form Health Survey (SF-36), Personal and Social Performance Scale (PSP) and the Positive and Negative Syndrome Scale (PANSS). We used BACS composite score as the main outcome measure. Repeated measures analysis of variance on BACS composite score showed significant effect of 'Time' (P schizophrenia could reflect a general problem of translating cognitive-enhancing effects of GLP-1RAs from animals to humans or be explained by factors specifically related to schizophrenia spectrum patients with obesity such as antipsychotic treatment. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Treatment with a GLP-1 receptor agonist diminishes the decrease in free plasma leptin during maintenance of weight loss

    DEFF Research Database (Denmark)

    Iepsen, E W; Lundgren, J; Dirksen, C

    2015-01-01

    of weight gain, low-calorie diet products were allowed to replace up to two meals per day to achieve equal weight maintenance. Glucose tolerance and hormone responses were investigated before and after weight loss and after 52 weeks weight maintenance. Primary end points: increase in soluble leptin receptor.......3 kg (95% CI=-0.6 to -4.0)), and had fewer meal replacements per day compared with the control group (minus one meal per day (95% CI=-0.6 to -1)), P....3±0.1 mmol l(-1) to the level before weight loss (-0.5mmol l(-1) (95% CI=-0.1 to -0.9)), PMeal response of peptide PYY3-36 was higher at week 52 in the GLP-1RA group compared with the control group, P

  14. Glucose-Lowering Effects and Low Risk of Hypoglycemia in Patients With Maturity-Onset Diabetes of the Young When Treated With a GLP-1 Receptor Agonist

    DEFF Research Database (Denmark)

    Ostoft, S. H.; Bagger, J. I.; Hansen, Torben

    2014-01-01

    OBJECTIVE The most common form of maturity-onset diabetes of the young (MODY), hepatocyte nuclear factor 1 alpha (HNF1A diabetes: MODY3) is often treated with sulfonylureas that confer a high risk of hypoglycemia. We evaluated treatment with GLP-1 receptor agonists (GLP-1RAs) in patients with HNF1A...... diabetes. RESEARCH DESIGN AND METHODS Sixteen patients with HNF1A diabetes (8 women; mean age 39 years [range 23-67 years]; BMI 24.9 +/- 0.5 kg/m(2) [mean +/- SEM]; fasting plasma glucose [FPG] 9.9 +/- 0.9 mmol/L; HbA(1c) 6.4 +/- 0.2% [47 +/- 3 mmol/mol]) received 6 weeks of treatment with a GLP-1RA...

  15. Heart rate acceleration with GLP-1 receptor agonists in type 2 diabetes patients : an acute and 12-week randomised, double-blind, placebo-controlled trial

    NARCIS (Netherlands)

    Smits, Mark M; Tonneijck, Lennart; Muskiet, Marcel H A; Hoekstra, T.; Kramer, Mark H H; Diamant, Michaela; van Raalte, Daniël H

    OBJECTIVE: To examine mechanisms underlying resting heart rate (RHR) increments of GLP-1 receptor agonists in type 2 diabetes patients. DESIGN: Acute and 12-week randomised, placebo-controlled, double-blind, single-centre, parallel-group trial. METHODS: In total, 57 type 2 diabetes patients

  16. The Extracellular Surface of the GLP-1 Receptor Is a Molecular Trigger for Biased Agonism.

    Science.gov (United States)

    Wootten, Denise; Reynolds, Christopher A; Smith, Kevin J; Mobarec, Juan C; Koole, Cassandra; Savage, Emilia E; Pabreja, Kavita; Simms, John; Sridhar, Rohan; Furness, Sebastian G B; Liu, Mengjie; Thompson, Philip E; Miller, Laurence J; Christopoulos, Arthur; Sexton, Patrick M

    2016-06-16

    Ligand-directed signal bias offers opportunities for sculpting molecular events, with the promise of better, safer therapeutics. Critical to the exploitation of signal bias is an understanding of the molecular events coupling ligand binding to intracellular signaling. Activation of class B G protein-coupled receptors is driven by interaction of the peptide N terminus with the receptor core. To understand how this drives signaling, we have used advanced analytical methods that enable separation of effects on pathway-specific signaling from those that modify agonist affinity and mapped the functional consequence of receptor modification onto three-dimensional models of a receptor-ligand complex. This yields molecular insights into the initiation of receptor activation and the mechanistic basis for biased agonism. Our data reveal that peptide agonists can engage different elements of the receptor extracellular face to achieve effector coupling and biased signaling providing a foundation for rational design of biased agonists. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  17. GLP-1/glucagon receptor co-agonism for treatment of obesity.

    Science.gov (United States)

    Sánchez-Garrido, Miguel A; Brandt, Sara J; Clemmensen, Christoffer; Müller, Timo D; DiMarchi, Richard D; Tschöp, Matthias H

    2017-10-01

    Over a relatively short period, obesity and type 2 diabetes have come to represent a large medical and economic burden to global societies. The epidemic rise in the prevalence of obesity has metabolic consequences and is paralleled by an increased occurrence of other diseases, such as diabetes, cancer and cardiovascular complications. Together, obesity and type 2 diabetes constitute one of the more preventable causes of premature death and the identification of novel, safe and effective anti-obesity drugs is of utmost importance. Pharmacological attempts to treat obesity have had limited success, with notable adverse effects, rendering bariatric surgery as the only current therapy for substantially improving body weight. Novel unimolecular, multifunctional peptides have emerged as one of the most promising medicinal approaches to enhance metabolic efficacy and restore normal body weight. In this review, we will mainly focus on the discovery and translational relevance of dual agonists that pharmacologically function at the receptors for glucagon and glucagon-like peptide-1. Such peptides have advanced to clinical evaluation and inspired the pursuit of multiple related approaches to achieving polypharmacy within single molecules.

  18. Efficacy and Safety of GLP-1 Receptor Agonists for Type 2 Diabetes Mellitus Treatment: Systematic Review

    Directory of Open Access Journals (Sweden)

    Ana Paula Martins

    2016-04-01

    Full Text Available Introduction: Glucagon-like peptide analogues are a new class of drugs used in the treatment of type 2 diabetes mellitus that mimic the endogenous hormone glucagon-like peptide 1. Glucagon-like peptide 1 regulates glucose levels by stimulating glucose-dependent insulin secretion, suppressing glucagon secretion, delayed gastric emptying and promoting satiety. The individualized treatment of type 2 diabetes mellitus, using various glucagon--like peptide receptor agonists, has recently been described and the interest related to these drugs continues to grow. Objectives: To review the efficacy and safety of glucagon-like peptide 1 agonists in patients with inadequately controlled type 2 diabetes mellitus on metformin alone, highlighting their added value in therapeutic use comparatively to second line oral therapies used in type 2 diabetes mellitus. Methods: Studies were obtained from electronic searches of The Cochrane Library and PubMed. Randomized controlled trials were selected if they were at least 8 weeks in duration; compared a glucagon-like peptide 1 analogue with an oral anti-diabetic agent in patients experiencing inadequate glycemic control with metformin monotherapy; and reported hemoglobin A1c data in non-pregnant adults with type 2 diabetes mellitus. Results: Of 72 potentially relevant articles identified, 23 were retrieved for detailed evaluation and 10 met the inclusion criteria. The majority of glucagon-like peptide 1 agonists showed equivalent or superior efficacy than most active comparators for reducing hemoglobin A1c, with a greater proportion of patients achieving hemoglobin A1c <7%. Glucagon-like peptide 1 agonists also showed extra-glycemic effects such as weight loss and the reduction of important cardiovascular parameters. Side effects included gastrointestinal complications, mainly nausea, vomiting and diarrhea. The incidence of hypoglycemia was less common for this class of agents. Conclusion: Glucagon-like peptide 1

  19. Reasons for discontinuation of GLP1 receptor agonists: data from a real-world cross-sectional survey of physicians and their patients with type 2 diabetes

    Directory of Open Access Journals (Sweden)

    Sikirica MV

    2017-09-01

    Full Text Available Mirko V Sikirica,1 Alan A Martin,2 Robert Wood,3 Andrea Leith,3 James Piercy,3 Victoria Higgins3 1Value Evidence and Outcomes, GlaxoSmithKline, Collegeville, PA, USA; 2Value Evidence and Outcomes, GlaxoSmithKline, London, UK; 3Diabetes, Adelphi Real World, Bollington, Cheshire, UK Aim: Nonadherence to glucagon-like peptide-1 receptor agonists (GLP1 RAs is relatively common among patients with type 2 diabetes mellitus (T2DM. This study sought to identify reasons why patients discontinue GLP1 RAs.Materials and methods: Retrospective data from the Adelphi Diabetes Disease Specific Programme were used. Physicians managing patients with T2DM were surveyed via face-to-face interviews, and patients treated for T2DM were surveyed via self-completed questionnaires. Patient data were stratified by current versus prior GLP1 RA use.Results: Physicians (n=443 most frequently reported inadequate blood glucose control (45.6%, nausea/vomiting (43.8%, and gastrointestinal (GI side effects (36.8% as reasons for GLP1 RA discontinuation. Patients (n=194 reported the GI-related issues “Made me feel sick” (64.4% and “Made me throw up” (45.4% as their top reasons for discontinuation. The most common problems reported (excluding cost for those currently using GLP1 RAs were “Prefer oral medication over injections” (patients 56%, physicians 32.6%, “Made me feel sick” (patients 38.1%, physicians 16.3%, and “Did not help lose weight” (patients 25.4%, physicians 18%. The most bothersome problems for patients globally (frequency reporting very/extremely bothersome (excluding cost were “Difficult to plan meals around” (55.6%, “Made me throw up” (51.6%, and “Caused weight gain” (50%.Conclusion: Both patients and physicians reported GI-related issues as a prominent factor, but disparities between patient experiences and physician perceptions were revealed, suggesting gaps in physician–patient communication. Understanding patients

  20. Mody-3: novel HNF1A mutation and the utility of glucagon-like peptide (GLP)-1 receptor agonist therapy.

    Science.gov (United States)

    Docena, Maricor K; Faiman, Charles; Stanley, Christine M; Pantalone, Kevin M

    2014-02-01

    An estimated 1 to 2% of cases of diabetes mellitus have a monogenic basis; however, delayed diagnosis and misdiagnosis as type 1 and 2 diabetes are common. Correctly identifying the molecular basis of an individual's diabetes may significantly alter the management approach to both the patient and his or her relatives. We describe a case of mature onset diabetes of the young (MODY) with sufficient evidence to support the classification of a novel HNF1A (hepatocyte nuclear factor-1-α) mutation as a cause of MODY-3. A 21-year-old Caucasian female presented to our office with a diagnosis of noninsulin-dependent diabetes mellitus (NIDDM) at age 10; glycemia was initially managed with oral antidiabetic (OAD) agents and insulin detemir. The patient reported a strong family history of early-onset NIDDM in both her mother and maternal grandmother, both of whom eventually required insulin therapy to control glycemia. The patient's medical and family history were highly suggestive of maturity-onset diabetes of the young (MODY), and genetic testing was performed. Genetic screening detected a mutation p. Arg200Trp in the HNF1A gene in the patient, her mother, and maternal grandmother, suggesting a diagnosis of MODY-3. This finding resulted in a change of antidiabetic therapy in all 3 patients, including the addition of once-daily liraglutide therapy, which helped improve their glycemic control. Our case report supports the classification of the p. Arg200Trp mutation as a cause of MODY-3. The findings also suggest that glucagon-like peptide-1 (GLP-1) receptor agonist therapy may be of value in managing glycemia in patients with MODY-3.

  1. GLP-1 Receptor Agonists

    Science.gov (United States)

    ... Peer Support Resources Diseases and Conditions Adrenal Disorders Osteoporosis and Bone Health Children and Teen Health Diabetes Heart Health Men's Health Rare Diseases Pituitary Disorders Thyroid Disorders Transgender Health Obesity and Weight Management Women's Health You and Your ...

  2. β cell membrane remodelling and procoagulant events occur in inflammation-driven insulin impairment: a GLP-1 receptor dependent and independent control.

    Science.gov (United States)

    Gleizes, Céline; Kreutter, Guillaume; Abbas, Malak; Kassem, Mohamad; Constantinescu, Andrei Alexandru; Boisramé-Helms, Julie; Yver, Blandine; Toti, Florence; Kessler, Laurence

    2016-02-01

    Inflammation and hyperglycaemia are associated with a prothrombotic state. Cell-derived microparticles (MPs) are the conveyors of active procoagulant tissue factor (TF) and circulate at high concentration in diabetic patients. Liraglutide, a glucagon-like peptide (GLP)-1 analogue, is known to promote insulin secretion and β-cell preservation. In this in vitro study, we examined the link between insulin impairment, procoagulant activity and plasma membrane remodelling, under inflammatory conditions. Rin-m5f β-cell function, TF activity mediated by MPs and their modulation by 1 μM liraglutide were examined in a cell cross-talk model. Methyl-β-cyclodextrine (MCD), a cholesterol depletor, was used to evaluate the involvement of raft on TF activity, MP shedding and insulin secretion as well as Soluble N-éthylmaleimide-sensitive-factor Attachment protein Receptor (SNARE)-dependent exocytosis. Cytokines induced a two-fold increase in TF activity at MP surface that was counteracted by liraglutide. Microparticles prompted TF activity on the target cells and a two-fold decrease in insulin secretion via protein kinase A (PKA) and p38 signalling, that was also abolished by liraglutide. Large lipid raft clusters were formed in response to cytokines and liraglutide or MCD-treated cells showed similar patterns. Cells pre-treated by saturating concentration of the GLP-1r antagonist exendin (9-39), showed a partial abolishment of the liraglutide-driven insulin secretion and liraglutide-decreased TF activity. Measurement of caspase 3 cleavage and MP shedding confirmed the contribution of GLP-1r-dependent and -independent pathways. Our results confirm an integrative β-cell response to GLP-1 that targets receptor-mediated signalling and membrane remodelling pointing at the coupling of insulin secretion and inflammation-driven procoagulant events. © 2015 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and

  3. GLP-1 agonists for type 2 diabetes

    DEFF Research Database (Denmark)

    Jespersen, Maria J; Knop, Filip K; Christensen, Mikkel

    2013-01-01

    and legal documents in the form of assessment reports from the European Medicines Agency and the United States Food and Drug Administration. EXPERT OPINION: GLP-1-based therapy combines several unique mechanisms of action and have the potential to gain widespread use in the fight against diabetes......Within recent years, glucagon-like peptide 1 receptor agonists (GLP-1-RA) have emerged as a new treatment option for type 2 diabetes. The GLP-1-RA are administered subcutaneously and differ substantially in pharmacokinetic profiles. AREAS COVERED: This review describes the pharmacokinetics...

  4. Treatment with GLP1 receptor agonists reduce serum CRP concentrations in patients with type 2 diabetes mellitus: A systematic review and meta-analysis of randomized controlled trials.

    Science.gov (United States)

    Mazidi, Mohsen; Karimi, Ehsan; Rezaie, Peyman; Ferns, Gordon A

    2017-07-01

    To undertake a systematic review and meta-analysis of randomized controlled trials of the effect of glucagon-like peptide-1 receptor agonist (GLP-1 RAs) therapy on serum C-reactive protein (CRP) concentrations. PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases were searched for the period up until March 16, 2016. Prospective studies evaluating the impact of GLP-1 RAs on serum CRP were identified. A random effects model (using the DerSimonian-Laird method) and generic inverse variance methods were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. Heterogeneity was quantitatively assessed using the I 2 index. Random effects meta-regression was performed using unrestricted maximum likelihood method to evaluate the impact of potential moderator. International Prospective Register for Systematic Reviews (PROSPERO) number CRD42016036868. Meta-analysis of the data from 7 treatment arms revealed a significant reduction in serum CRP concentrations following treatment with GLP-1 RAs (WMD -2.14 (mg/dL), 95% CI -3.51, -0.78, P=0.002; I 2 96.1%). Removal of one study in the meta-analysis did not change the result in the sensitivity analysis (WMD -2.14 (mg/dL), 95% CI -3.51, -0.78, P=0.002; I 2 96.1%), indicating that our results could not be solely attributed to the effect of a single study. Random effects meta-regression was performed to evaluate the impact of potential moderator on the estimated effect size. Changes in serum CRP concentration were associated with the duration of treatment (slope -0.097, 95% CI -0.158, -0.042, Pmeta-analysis suggests that GLP-1 RAs therapy causes a significant reduction in CRP. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. GLP-1 receptor agonist treatment increases bone formation and prevents bone loss in weight-reduced obese women

    DEFF Research Database (Denmark)

    Iepsen, Eva Pers Winning; Lundgren, Julie Rehné; Hartmann, Bolette

    2015-01-01

    with or without administration of the GLP-1 RA liraglutide (1.2mg/day) for 52 weeks. In case of weight gain, up to two meals per day could be substituted with a low-calorie diet product in order to maintain the weight loss. MAIN OUTCOME MEASURES: Total, pelvic and arm-leg bone mineral content (BMC) and bone...... markers (CTX-1 and P1NP) were investigated before, after weight loss and after 52 weeks weight maintenance. Primary end points: Change in BMC and bone markers after 52 weeks weight maintenance with or without GLP-1 RA treatment. RESULTS: Total, pelvic and arm-leg BMC decreased during weight maintenance...... in the control group (ptotal and arm-leg BMC loss was 4 times greater in the control group compared to the liraglutide group (estimated difference 27g (95% CI 5-48), p=0.01), although the 12% weight loss was maintained in both groups...

  6. Effect of GLP-1 receptor agonist treatment on body weight in obese antipsychotic-treated patients with schizophrenia: a randomized, placebo-controlled trial.

    Science.gov (United States)

    Ishøy, Pelle L; Knop, Filip K; Broberg, Brian V; Bak, Nikolaj; Andersen, Ulrik B; Jørgensen, Niklas R; Holst, Jens J; Glenthøj, Birte Y; Ebdrup, Bjørn H

    2017-02-01

    Schizophrenia is associated with cardiovascular co-morbidity and a reduced life-expectancy of up to 20 years. Antipsychotics are dopamine D 2 receptor antagonists and are the standard of medical care in schizophrenia, but the drugs are associated with severe metabolic side effects such as obesity and diabetes. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are registered for treatment of both obesity and type 2 diabetes. We investigated metabolic effects of the GLP-1RA, exenatide once-weekly, in non-diabetic, antipsychotic-treated, obese patients with schizophrenia. Antipsychotic-treated, obese, non-diabetic, schizophrenia spectrum patients were randomized to double-blinded adjunctive treatment with once-weekly subcutaneous exenatide (n = 23) or placebo (n = 22) injections for 3 months. The primary outcome was loss of body weight after treatment and repeated measures analysis of variance was used as statistical analysis. Between March 2013 and June 2015, 40 patients completed the trial. At baseline, mean body weight was 118.3 ± 16.0 kg in the exenatide group and 111.7 ± 18.0 kg in the placebo group, with no group differences ( P = .23). The exenatide and placebo groups experienced significant ( P = .004), however similar ( P = .98), weight losses of 2.24 ± 3.3 and 2.23 ± 4.4 kg, respectively, after 3 months of treatment. Treatment with exenatide once-weekly did not promote weight loss in obese, antipsychotic-treated patients with schizophrenia compared to placebo. Our results could suggest that the body weight-lowering effect of GLP-1RAs involves dopaminergic signaling, but blockade of other receptor systems may also play a role. Nevertheless, anti-obesity regimens effective in the general population may not be readily implemented in antipsychotic-treated patients with schizophrenia. © 2016 The Authors. Diabetes, Obesity and Metabolism published by John Wiley & Sons Ltd.

  7. A novel dual GLP-1 and GIP incretin receptor agonist is neuroprotective in a mouse model of Parkinson’s disease by reducing chronic inflammation in the brain

    OpenAIRE

    Lijun, Cao; Li, Dongfang; Feng, Peng; Li, Lin; Xue, Guofang; Li, Guanglai; Holscher, Christian

    2016-01-01

    The incretins glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are growth factors. GLP-1 mimetics are on the market as treatments for type 2 diabetes. Both GLP-1 and GIP mimetics have shown neuroprotective properties in previous studies. In addition, the GLP-1 mimetic exendin-4 has shown protective effects in a clinical trial in Parkinson’s disease (PD) patients. Novel GLP-1/GIP dual-agonist peptides have been developed to treat diabetes. Here, we report ...

  8. Effect of Oxyntomodulin, Glucagon, GLP-1 and Combined Glucagon +GLP-1 Infusion on Food Intake, Appetite and Resting Energy Expenditure

    DEFF Research Database (Denmark)

    Bagger, Jonatan I; Holst, Jens J; Hartmann, Bolette

    2015-01-01

    Context: The gut hormone, oxyntomodulin, is a proglucagon product with body weight-lowering potential. It binds to both the glucagon-like peptide-1 (GLP-1) receptor and the glucagon receptor; however, the mechanism behind the body weight-lowering effect remains elusive. Objective: We wanted.......86 pmol × kg−1 × min−1), oxyntomodulin (3 pmol × kg−1 × min−1), or glucagon+GLP-1 (same doses). Main Outcome Measures: We evaluated resting energy expenditure (measured as oxygen uptake, gastric emptying (GE), composite appetite scores (CAS), and food intake. Results: Oxyntomodulin, GLP-1, and GLP-1...

  9. Treatment of antipsychotic-associated obesity with a GLP-1 receptor agonist--protocol for an investigator-initiated prospective, randomised, placebo-controlled, double-blinded intervention study

    DEFF Research Database (Denmark)

    Ishøy, Pelle L; Knop, Filip K; Broberg, Brian V

    2014-01-01

    -associated obesity are limited and insufficient. Glucagon-like peptide-1 (GLP-1) receptor agonists are approved for the treatment of type 2 diabetes, but their bodyweight-lowering effects have also been recognised in patients with non-diabetes. The primary endpoint of this trial is weight loss after 3 months...... of treatment with a GLP-1 receptor agonist (exenatide once weekly) in patients with non-diabetic schizophrenia with antipsychotic-associated obesity. Secondary endpoints include physiological and metabolic measurements, various psychopathological and cognitive measures, and structural and functional brain MRI....

  10. A Systematic Literature Review and Network Meta-Analysis Comparing Once-Weekly Semaglutide with Other GLP-1 Receptor Agonists in Patients with Type 2 Diabetes Previously Receiving 1-2 Oral Anti-Diabetic Drugs.

    Science.gov (United States)

    Witkowski, Michal; Wilkinson, Lars; Webb, Neil; Weids, Alan; Glah, Divina; Vrazic, Hrvoje

    2018-04-19

    Once-weekly semaglutide is a new glucagon-like peptide-1 (GLP-1) analogue administered at a 1.0 or 0.5 mg dose. As head-to-head trials assessing once-weekly semaglutide as an add-on to 1-2 oral anti-diabetic drugs (OADs) vs other GLP-1 receptor agonists (GLP-1 RAs) are limited, a network meta-analysis (NMA) was performed. The objective was to assess the relative efficacy and safety of once-weekly semaglutide vs GLP-1 RAs in patients with type 2 diabetes (T2D) inadequately controlled on 1-2 OADs. A systematic literature review (SLR) was conducted in order to identify trials of GLP-1 RAs in patients inadequately controlled on 1-2 OADs. Data at 24 ± 4 weeks were extracted for efficacy and safety outcomes (feasible for analysis in a NMA), which included the key outcomes of change from baseline in glycated hemoglobin (HbA 1c ), systolic blood pressure (SBP), and weight, as well as discontinuation due to adverse events (AEs). Data were synthesized using a NMA and a Bayesian framework. In total, 26 studies were included across the base case analyses. Once-weekly semaglutide 1.0 mg was associated with significantly greater reductions in HbA 1c and weight vs all GLP-1 RA comparators. Once-weekly semaglutide 0.5 mg also achieved significantly greater reductions in HbA 1c and weight compared with the majority of other GLP-1 RAs. Both doses of once-weekly semaglutide were associated with similar odds of discontinuation due to AEs compared with other GLP-1 RAs. Overall, once-weekly semaglutide 1.0 mg as an add-on to 1-2 OADs is the most efficacious GLP-1 RA in terms of the reduction of HbA 1c and weight from baseline after 6 months of treatment. In addition, the analysis suggests that once-weekly semaglutide is well tolerated and not associated with an increase in discontinuations due to AEs compared with other GLP-1 RAs. Novo Nordisk.

  11. GLP-1 and Amylin in the Treatment of Obesity

    DEFF Research Database (Denmark)

    Jorsal, T; Rungby, J; Knop, F K

    2016-01-01

    for treatment of diabetes and obesity. This review will outline the physiology and pharmacological potential of amylin and GLP-1, respectively, and focus on innovative peptide drug development leading to drugs acting on two or more distinct receptors, such as an amylin and GLP-1 peptide hybrid, potentially...... producing a more effective treatment strategy to combat the rapidly increasing global obesity....

  12. The central GLP-1: implications for food and drug reward

    Directory of Open Access Journals (Sweden)

    Karolina Patrycja Skibicka

    2013-10-01

    Full Text Available Glucagon-like-peptide-1 (GLP-1 and its long acting analogues comprise a novel class of type 2 diabetes (T2D treatment. What makes them unique among other T2D drugs is their concurrent ability to reduce food intake, a great benefit considering the frequent comorbidity of T2D and obesity. The precise neural site of action underlying this beneficial effect is vigorously researched. In accordance with the classical model of food intake control GLP-1 action on feeding has been primarily ascribed to receptor populations in the hypothalamus and the hindbrain. In contrast to this common view, relevant GLP-1 receptor populations are distributed more widely, with a prominent mesolimbic complement emerging. The physiological relevance of the mesolimbic GLP-1 is suggested by the demonstration that similar anorexic effects can be obtained by independent stimulation of the mesolimbic and hypothalamic GLP-1 receptors. Results reviewed here support the idea that mesolimbic GLP-1 receptors are sufficient to reduce hunger-driven feeding, the hedonic value of food and food-motivation. In parallel, emerging evidence suggests that the range of action of GLP-1 on reward behavior is not limited to food-derived reward but extends to cocaine, amphetamine and alcohol reward. The new discoveries concerning GLP-1 action on the mesolimbic reward system significantly extend the potential therapeutic range of this drug target.

  13. Glucagon-like peptide-1 (GLP-1) receptor agonism or DPP-4 inhibition does not accelerate neoplasia in carcinogen treated mice

    DEFF Research Database (Denmark)

    Kissow, Hannelouise; Hartmann, Bolette; Holst, Jens Juul

    2012-01-01

    Glucagon-like peptide-1 (GLP-1) and glucagon-like peptide-2 (GLP-2) are secreted in parallel from the intestinal endocrine cells after nutrient intake. GLP-1 is an incretin hormone and analogues are available for the treatment of type 2 diabetes mellitus (T2DM). GLP-2 is an intestinal growth horm...

  14. Renal effects of DPP-4 inhibitor sitagliptin or GLP-1 receptor agonist liraglutide in overweight patients with type 2 diabetes : A 12-week, randomized, double-blind, placebo-controlled trial

    NARCIS (Netherlands)

    Tonneijck, Lennart; Smits, Mark M.; Muskiet, Marcel H A; Hoekstra, Trynke; Kramer, Mark H H; Danser, A. H Jan; Ter Wee, Piet M.; Diamant, Michaela; Joles, Jaap A.; Van Raalte, Daniël H.

    2016-01-01

    OBJECTIVE To investigate effects of dipeptidyl peptidase-4 inhibitor (DPP-4I) sitagliptin or glucagon-like peptide 1 (GLP-1) receptor agonist liraglutide treatment on renal hemodynamics, tubular functions, and markers of renal damage in overweight patients with type 2 diabetes without chronic kidney

  15. Treatment of antipsychotic-associated obesity with a GLP-1 receptor agnoist: Protocol for an investigator-initiated prospective, randomised, placebo-controlled, double-blinded intervention study - the TAO study

    DEFF Research Database (Denmark)

    Ishøy, Pelle Lau; Knop, Filip Krag; Broberg, Brian Villumsen

    with a GLP-1 receptor agonist (exenatide once-weekly) is safe and facilitates weight loss in non-diabetic schizophrenia patients with antipsychotic-associated obesity. Materials and methods: Forty obese patients with schizophrenia or schizoaffective disorder treated with antipsychotic drugs...

  16. Treatment of antipsychotic-associated obesity with a GLP-1 receptor agonist: Protocol for an investigator-initiated prospective, randomised, placebo-controlled, double-blinded intervention study – the TAO study

    DEFF Research Database (Denmark)

    Ishøy, Pelle Lau; Knop, Filip Krag; Broberg, Brian Villumsen

    with a GLP-1 receptor agonist (exenatide once-weekly) is safe and facilitates weight loss in non-diabetic schizophrenia patients with antipsychotic-associated obesity. Methods and analysis: Forty obese patients with schizophrenia or schizoaffective disorder treated with antipsychotic drugs will be randomised...

  17. SGLT2 inhibitors or GLP-1 receptor agonists as second-line therapy in type 2 diabetes: patient selection and perspectives

    Directory of Open Access Journals (Sweden)

    Gurgle HE

    2016-06-01

    Full Text Available Holly E Gurgle, Karen White, Carrie McAdam-Marx Department of Pharmacotherapy, University of Utah College of Pharmacy, Salt Lake City, UT, USA Abstract: Controversy exists regarding the selection of second-line therapy for patients with type 2 diabetes mellitus (T2DM who are unable to achieve glycemic control with metformin therapy alone. Newer pharmacologic treatments for T2DM include glucagon-like peptide-1 receptor agonists and sodium–glucose cotransporter 2 inhibitors. Both the classes of medication are efficacious, exhibit positive effects on weight, and are associated with minimal risk of hypoglycemia. The purpose of this review is to compare the clinical trial and real-world effectiveness data of glucagon-like peptide-1 receptor agonists versus sodium–glucose cotransporter 2 inhibitors related to A1c reduction, weight loss, cost-effectiveness, cardiovascular outcomes, and safety in patients with T2DM. This review summarizes comparative evidence for providers who are determining which of the two classes may be the most appropriate for a specific patient. Keywords: type 2 diabetes mellitus, GLP-1 receptor agonist, SGLT2 inhibitor, A1c, weight loss, adverse effect

  18. Evaluation of an [18F]AlF-NOTA Analog of Exendin-4 for Imaging of GLP-1 Receptor in Insulinoma

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    Dale O. Kiesewetter, Ning Guo, Jinxia Guo, Haokao Gao, Lei Zhu, Ying Ma, Gang Niu, Xiaoyuan Chen

    2012-01-01

    Full Text Available Introduction: The GLP-1 receptor plays an important role in glucose homeostasis and thus is a very important target for diabetes therapy. The receptor is also overexpressed in insulinoma, a tumor of pancreatic beta-cells. We previously evaluated two fluorine-18-labeled analogs of exendin-4 prepared by conjugation with [18F]FBEM (N-[2-(4-[18F]fluorobenzamideethyl]maleimide. Both compounds demonstrated good tumor uptake, but the synthesis of the radiotracers was time consuming. To overcome this challenge, we developed a NOTA analog and performed radiolabeling using aluminum [18F]fluoride complexation.Methods: Cys40-exendin-4 was conjugated with NOTA mono N-ethylmaleimide. [18F]AlF conjugation was conducted and the radiolabeled product purified by preparative HPLC. Dynamic and static PET imaging scans were conducted on nude mice with established INS-1 xenografts. Uptake of tumor and other major organs in static images was quantitated (%ID/g and comparison with blocking studies was made. PET quantification was also compared with ex vivo biodistribution results.Results: The radiosynthesis provided [18F]AlF-NOTA-MAL-cys40-exendin-4 in 23.6 ± 2.4 % radiochemical yield (uncorrected, n = 3 after HPLC; the process required about 55 min. The specific activity at time of injection ranged from 19.6 to 31.4 GBq (0.53-0.85 Ci/µmol. Tumor uptake had reached its maximum (16.09 ± 1.18% ID/g, n = 4 by 5 min and remained nearly constant for the duration of the study. Kidney uptake continued to increase throughout the entire one hour time course. Pre-injection of exendin-4 caused a marked reduction in tissue uptake with the major exception of liver and kidneys, in which uptake was not affected. HPLC analysis of the radioactive components in extracts of the tumor and plasma showed primarily parent compound at 60 min post-injection, whereas extracts of kidney and urine contained exclusively one polar radioactive component.Conclusion: The radiotracer is prepared in

  19. Neuroprotective properties of GLP-1

    DEFF Research Database (Denmark)

    Holst, Jens Juul; Burcelin, Remy; Nathanson, Esther

    2011-01-01

    emptying. Furthermore, data are beginning to emerge that indicate a potential role for GLP-1 in neuroprotection. The increased risk of Alzheimer's disease, Parkinson's disease and stroke in people with type 2 diabetes suggests that shared mechanisms/pathways of cell death, possibly related to insulin...... path towards cellular dysfunction and death. This article summarizes the evidence for neuronal activity of GLP-1 and examines the limited data that currently exist on the therapeutic potential of GLP-1 in specific neurological and neurodegenerative conditions, namely Alzheimer's disease, Parkinson...

  20. GLP-1 defects in diabetes

    DEFF Research Database (Denmark)

    Janus, Charlotte; Albrechtsen, Nicolai Jacob Wewer; Holst, Jens Juul

    2015-01-01

    with type 2 diabetes (T2D) but the underlying mechanisms are still incompletely understood. In subjects with impaired glucose tolerance (IGT) and T2D, reduced levels of circulating GLP-1 have been observed in cross-sectional studies. Regardless of other changes, a reduced GLP-1 secretion must result...... glucose disturbances to frank diabetes. Therefore, further studies are required. Ideally, longitudinal studies of predisposed subjects (i.e. obesity, first-degree relatives, post gestational diabetes) followed until diagnosis of T2D would be necessary for elucidating if, indeed, impaired GLP-1 secretion......Glucagon-like peptide-1 (GLP-1) is secreted from the intestinal L-cells upon nutrient stimulation and regulates glucose levels by stimulating secretion of insulin (insulinotropic effects) in a glucose-dependent manner (the incretin effect). The incretin effect is severely impaired in subjects...

  1. Proteomic analysis of INS-1 rat insulinoma cells: ER stress effects and the protective role of exenatide, a GLP-1 receptor agonist.

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    Mi-Kyung Kim

    Full Text Available Beta cell death caused by endoplasmic reticulum (ER stress is a key factor aggravating type 2 diabetes. Exenatide, a glucagon-like peptide (GLP-1 receptor agonist, prevents beta cell death induced by thapsigargin, a selective inhibitor of ER calcium storage. Here, we report on our proteomic studies designed to elucidate the underlying mechanisms. We conducted comparative proteomic analyses of cellular protein profiles during thapsigargin-induced cell death in the absence and presence of exenatide in INS-1 rat insulinoma cells. Thapsigargin altered cellular proteins involved in metabolic processes and protein folding, whose alterations were variably modified by exenatide treatment. We categorized the proteins with thapsigargin initiated alterations into three groups: those whose alterations were 1 reversed by exenatide, 2 exaggerated by exenatide, and 3 unchanged by exenatide. The most significant effect of thapsigargin on INS-1 cells relevant to their apoptosis was the appearance of newly modified spots of heat shock proteins, thimet oligopeptidase and 14-3-3β, ε, and θ, and the prevention of their appearance by exenatide, suggesting that these proteins play major roles. We also found that various modifications in 14-3-3 isoforms, which precede their appearance and promote INS-1 cell death. This study provides insights into the mechanisms in ER stress-caused INS-1 cell death and its prevention by exenatide.

  2. A novel dual GLP-1 and GIP incretin receptor agonist is neuroprotective in a mouse model of Parkinson's disease by reducing chronic inflammation in the brain.

    Science.gov (United States)

    Cao, Lijun; Li, Dongfang; Feng, Peng; Li, Lin; Xue, Guo-Fang; Li, Guanglai; Hölscher, Christian

    2016-04-13

    The incretins glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are growth factors. GLP-1 mimetics are on the market as treatments for type 2 diabetes. Both GLP-1 and GIP mimetics have shown neuroprotective properties in previous studies. In addition, the GLP-1 mimetic exendin-4 has shown protective effects in a clinical trial in Parkinson's disease (PD) patients. Novel GLP-1/GIP dual-agonist peptides have been developed to treat diabetes. Here, we report the neuroprotective effects of a novel dual agonist (DA-JC1) in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. MPTP was injected once daily (20 mg/kg intraperitoneally) for 7 days and the dual agonist was coinjected once daily (50 nmol/kg intraperitoneally). We found that the drug reduced most of the MPTP-induced motor impairments in the rotarod, open-field locomotion, and muscle strength test. The number of tyrosine hydroxylase-positive neurons in the substantia nigra and striatum was reduced by MPTP and increased by DA-JC1. Synapse numbers (synaptophysin expression) were reduced in the substantia nigra and the striatum by MPTP and DA-JC1 reversed this effect. The activation of a chronic inflammation response by MPTP was considerably reduced by the dual agonist (DA) (astroglia and microglia activation). Therefore, dual agonists show promise as a novel treatment of PD.

  3. Loss of dorsomedial hypothalamic GLP-1 signaling reduces BAT thermogenesis and increases adiposity.

    Science.gov (United States)

    Lee, Shin J; Sanchez-Watts, Graciela; Krieger, Jean-Philippe; Pignalosa, Angelica; Norell, Puck N; Cortella, Alyssa; Pettersen, Klaus G; Vrdoljak, Dubravka; Hayes, Matthew R; Kanoski, Scott; Langhans, Wolfgang; Watts, Alan G

    2018-05-01

    Glucagon-like peptide-1 (GLP-1) neurons in the hindbrain densely innervate the dorsomedial hypothalamus (DMH), a nucleus strongly implicated in body weight regulation and the sympathetic control of brown adipose tissue (BAT) thermogenesis. Therefore, DMH GLP-1 receptors (GLP-1R) are well placed to regulate energy balance by controlling sympathetic outflow and BAT function. We investigate this possibility in adult male rats by using direct administration of GLP-1 (0.5 ug) into the DMH, knocking down DMH GLP-1R mRNA with viral-mediated RNA interference, and by examining the neurochemical phenotype of GLP-1R expressing cells in the DMH using in situ hybridization. GLP-1 administered into the DMH increased BAT thermogenesis and hepatic triglyceride (TG) mobilization. On the other hand, Glp1r knockdown (KD) in the DMH increased body weight gain and adiposity, with a concomitant reduction in energy expenditure (EE), BAT temperature, and uncoupling protein 1 (UCP1) expression. Moreover, DMH Glp1r KD induced hepatic steatosis, increased plasma TG, and elevated liver specific de-novo lipogenesis, effects that collectively contributed to insulin resistance. Interestingly, DMH Glp1r KD increased neuropeptide Y (NPY) mRNA expression in the DMH. GLP-1R mRNA in the DMH, however, was found in GABAergic not NPY neurons, consistent with a GLP-1R-dependent inhibition of NPY neurons that is mediated by local GABAergic neurons. Finally, DMH Glp1r KD attenuated the anorexigenic effects of the GLP-1R agonist exendin-4, highlighting an important role of DMH GLP-1R signaling in GLP-1-based therapies. Collectively, our data show that DMH GLP-1R signaling plays a key role for BAT thermogenesis and adiposity. Copyright © 2018 The Authors. Published by Elsevier GmbH.. All rights reserved.

  4. Gut peptide GLP-1 and its analogue, Exendin-4, decrease alcohol intake and reward.

    Directory of Open Access Journals (Sweden)

    Rozita H Shirazi

    Full Text Available Glucagon-like-peptide-1 (GLP-1 is a gut- and neuro-peptide with an important role in the regulation of food intake and glucose metabolism. Interestingly, GLP-1 receptors (GLP-1R are expressed in key mesolimbic reward areas (including the ventral tegmental area, VTA, innervated by hindbrain GLP-1 neurons. Recently GLP-1 has emerged as a potential regulator of food reward behavior, an effect driven by the mesolimbic GLP-1Rs. Its role in other reward behaviors remains largely unexplored. Since a considerable overlap has been suggested for circuitry controlling reward behavior derived from food and alcohol we hypothesized that GLP-1 and GLP-1Rs could regulate alcohol intake and alcohol reward. We sought to determine whether GLP-1 or its clinically safe stable analogue, Exendin-4, reduce alcohol intake and reward. To determine the potential role of the endogenous GLP-1 in alcohol intake we evaluated whether GLP-1R antagonist, Exendin 9-39, can increase alcohol intake. Furthermore, we set out to evaluate whether VTA GLP-1R activation is sufficient to reduce alcohol intake. Male Wistar rats injected peripherally with GLP-1 or Exendin-4 reduced their alcohol intake in an intermittent access two bottle free choice drinking model. Importantly, a contribution of endogenously released GLP-1 is highlighted by our observation that blockade of GLP-1 receptors alone resulted in an increased alcohol intake. Furthermore, GLP-1 injection reduced alcohol reward in the alcohol conditioned place preference test in mice. To evaluate the neuroanatomical substrate linking GLP-1 with alcohol intake/reward, we selectively microinjected GLP-1 or Exendin 4 into the VTA. This direct stimulation of the VTA GLP-1 receptors potently reduced alcohol intake. Our findings implicate GLP-1R signaling as a novel modulator of alcohol intake and reward. We show for the first time that VTA GLP-1R stimulation leads to reduced alcohol intake. Considering that GLP-1 analogues are already

  5. Effectiveness of Sodium-Glucose Cotransporter-2 Inhibitor as an Add-on Drug to GLP-1 Receptor Agonists for Glycemic Control of a Patient with Prader-Willi Syndrome: A Case Report.

    Science.gov (United States)

    Horikawa, Yukio; Enya, Mayumi; Komagata, Makie; Hashimoto, Ken-Ichi; Kagami, Masayo; Fukami, Maki; Takeda, Jun

    2018-02-01

    Diabetes patients with Prader-Willi syndrome (PWS) are obese because of hyperphagia; weight control by dietary modification and medicine is required for glycemic control. There are several recent reports showing the effectiveness of GLP-1 receptor agonists (GLP-1RAs) for diabetes treatment in PWS. A 36-year-old Japanese male patient was diagnosed with PWS at 10 years of age. At age 16 years, he was diagnosed with diabetes and began to take several kinds of oral hypoglycemic agents. At age 29 years, his BMI was 39.1 kg/m 2 and he was referred to our department for diabetes and obesity treatment. In the present case, the HbA1c was not improved by GLP-1RAs despite a 28-kg BW reduction, which included a 9-kg loss of muscle. Apprehensive of further loss of muscle mass, basal insulin of insulin glargine was administered in addition to GLP-1RAs. Immediately after the addition of tofogliflozin, a sodium-glucose cotransporter-2 (SGLT2) inhibitor, the patient's HbA1c decreased dramatically with only about an additional 3% BW reduction. We note an improvement in our case of lipid deposition in the pancreas confirmed by abdominal CT after the improvement of HbA1c. It is unknown whether this improvement of fatty pancreas was a cause or an effect of the improved glycemic control in the present case. This finding clearly supports the effectiveness of combining SGLT2 inhibitors with GLP-1RAs for treatment of patients with PWS and non-alcoholic fatty pancreas disease.

  6. Long-term Cost-effectiveness of Two GLP-1 Receptor Agonists for the Treatment of Type 2 Diabetes Mellitus in the Italian Setting: Liraglutide Versus Lixisenatide.

    Science.gov (United States)

    Hunt, Barnaby; Kragh, Nana; McConnachie, Ceilidh C; Valentine, William J; Rossi, Maria C; Montagnoli, Roberta

    2017-07-01

    Maintaining glycemic control is the key treatment target for patients with type 2 diabetes mellitus. In addition, the glucagon-like peptide-1 (GLP-1) receptor agonists may be associated with other favorable treatment characteristics, such as reduction in body weight and reduced risk of hypoglycemia compared with traditional diabetes interventions. The aim of the present analysis was to compare the long-term cost-effectiveness of 2 GLP-1 receptor agonists, liraglutide 1.8 mg and lixisenatide 20 μg (both administered once daily), in the treatment of patients with type 2 diabetes failing to achieve glycemic control with metformin monotherapy in the Italian setting. The IMS CORE Diabetes Model was used to project long-term clinical outcomes and subsequent costs (in 2015 Euros [€]) associated with liraglutide 1.8 mg versus lixisenatide 20 μg treatment in a cohort with baseline characteristics derived from the open-label LIRA-LIXI trial (Efficacy and Safety of Liraglutide Versus Lixisenatide as Add-on to Metformin in Subjects With Type 2 Diabetes; NCT01973231) over patient lifetimes from the perspective of a health care payer. Efficacy data were taken from the 26-week end points of the same trial, including changes in glycated hemoglobin, body mass index, serum lipid levels, and hypoglycemic event rates. Outcomes projected included life expectancy, quality-adjusted life expectancy, cumulative incidence and time to onset of diabetes-related complications, and direct medical costs. Outcomes were discounted at 3% annually, and sensitivity analyses were performed. Liraglutide 1.8 mg was associated with improved discounted life expectancy (14.07 vs 13.96 years) and quality-adjusted life expectancy (9.18 vs 9.06 quality-adjusted life years [QALYs]) compared with lixisenatide 20 μg. These improvements were mostly attributable to a greater reduction in glycated hemoglobin level with liraglutide 1.8 mg versus lixisenatide 20 μg, leading to reduced incidence and

  7. A novel dual GLP-1 and GIP receptor agonist is neuroprotective in the MPTP mouse model of Parkinson's disease by increasing expression of BNDF.

    Science.gov (United States)

    Ji, Chenhui; Xue, Guo-Fang; Lijun, Cao; Feng, Peng; Li, Dongfang; Li, Lin; Li, Guanglai; Hölscher, Christian

    2016-03-01

    The incretins glucagon-like peptide 1 (GLP-1) and glucose dependent insulinotropic polypeptide (GIP) are growth factors with neuroprotective properties. GLP-1 mimetics are on the market as treatments for type 2 diabetes and are well tolerated. Both GLP-1 and GIP mimetics have shown neuroprotective properties in animal models of Parkinson's and Alzheimer's disease. In addition, the GLP-1 mimetic exendin-4 has shown protective effects in a clinical trial in Parkinson's disease (PD) patients. Novel GLP-1/GIP dual-agonist peptides have been developed and are tested in diabetic patients. Here we demonstrate the neuroprotective effects of a novel dual agonist (DA-JC1) in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. MPTP was injected once-daily (20 mg/kg i.p.) for 7 days, and the dual agonist was injected 30 min later i.p. (50 nmol/kg bw). The PI3k inhibitor LY294002 (0.6 mg/kg i.v.) was co-injected in one group. DA-JC1 reduced or reversed most of the MPTP induced motor impairments in the rotarod and in a muscle strength test. The number of tyrosine hydroxylase (TH) positive neurons in the substantia nigra (SN) was reduced by MPTP and increased by DA-JC1. The ratio of anti-inflammatory Bcl-2 to pro-inflammatory BAX as well as the activation of the growth factor kinase Akt was reduced by MPTP and reversed by DA-JC1. The PI3k inhibitor had only limited effect on the DA-JC1 drug effect. Importantly, levels of the neuroprotective brain derived neurotropic factor (BDNF) were reduced by MPTP and enhanced by DA-JC1. The results demonstrate that DA-JC1 shows promise as a novel treatment for PD. Copyright © 2016. Published by Elsevier B.V.

  8. Evaluating preferences for profiles of GLP-1 receptor agonists among injection-naïve type 2 diabetes patients in the UK

    Directory of Open Access Journals (Sweden)

    Gelhorn HL

    2015-11-01

    . In this context, dosing frequency and type of delivery system were most important, accounting for over 75% of the RI. While previous studies have identified efficacy as highly important in T2DM medication decisions, this study suggests that when differences in efficacy between medications are small, other treatment features (eg, dosing frequency and delivery system are of much greater importance to patients. Keywords: discrete choice experiment, patient preference, type 2 diabetes, GLP-1 receptor agonist 

  9. Ability of GLP-1 to decrease food intake is dependent on nutritional status.

    Science.gov (United States)

    Ronveaux, Charlotte C; de Lartigue, Guillaume; Raybould, Helen E

    2014-08-01

    Gut-derived glucagon like peptide-1 (GLP-1) acts in the postprandial period to stimulate insulin secretion and inhibit gastrointestinal motor and secretory function; whether endogenous peripheral GLP-1 inhibits food intake is less clear. We hypothesized that GLP-1 inhibits food intake in the fed, but not fasted, state. There is evidence that GLP-1 acts via stimulation of vagal afferent neurons (VAN); we further hypothesized that the satiating effects of endogenous GLP-1 in the postprandial period is determined either by a change in GLP-1 receptor (GLP-1R) expression or localization to different cellular compartments in VAN. Food intake was recorded following administration of GLP-1 (50μg/kg or 100μg/kg) or saline (IP) in Wistar rats fasted for 18h or fasted then re-fed with 3g chow. GLP-1R protein expression and localization on VAN were determined by immunocytochemistry and immunoblots in animals fasted for 18h or fasted then re-fed for 40min. GLP-1R mRNA level was detected in animals fasted for 18h or fasted and re-fed ad libitum for 2h. GLP-1 (100μg/kg) significantly reduced 40min food intake by 38% in re-fed but not fasted rats (pfasted rats. However, GLP-1R localization to the plasma membrane was significantly increased in VAN by feeding. Feeding changes the ability of peripheral GLP-1 to inhibit food intake. GLP-1Rs are trafficked to the plasma membrane in response to a meal. GLP-1 may play a role in regulating food intake in the postprandial period. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. 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...

  11. GLP-1 improves neuropathology after murine cold lesion brain trauma

    DEFF Research Database (Denmark)

    DellaValle, Brian; Hempel, Casper; Johansen, Flemming Fryd

    2014-01-01

    brain trauma. METHODS: Severe trauma was induced with a stereotactic cryo-lesion in mice and thereafter treated with vehicle, liraglutide, or liraglutide + GLP-1 receptor antagonist. A therapeutic window was established and lesion size post-trauma was determined. Reactive oxygen species were visualized......-neurodegenerative proteins increased with Lira-driven CREB activation. INTERPRETATION: These results show that Lira has potent effects after experimental trauma in mice and thus should be considered a candidate for critical care intervention post-injury. Moreover, activation of CREB in the brain by Lira - described......OBJECTIVES: In this study, we address a gap in knowledge regarding the therapeutic potential of acute treatment with a glucagon-like peptide-1 (GLP-1) receptor agonist after severe brain trauma. Moreover, it remains still unknown whether GLP-1 treatment activates the protective, anti...

  12. The anorectic effect of GLP-1 in rats is nutrient dependent.

    Directory of Open Access Journals (Sweden)

    Darleen Sandoval

    Full Text Available GLP-1-induced insulin secretion from the β-cell is dependent upon glucose availability. The purpose of the current study was to determine whether CNS GLP-1 signaling is also glucose-dependent. We found that fasting blunted the ability of 3(rd cerebroventricularly (i3vt-administered GLP-1 to reduce food intake. However, fasted animals maintained the anorexic response to melanotan II, a melanocortin receptor agonist, indicating a specific effect of fasting on GLP-1 action. We also found that i3vt administration of leptin, which is also decreased with fasting, was not able to potentiate GLP-1 action in fasted animals. However, we did find that CNS glucose sensing is important in GLP-1 action. Specifically, we found that i3vt injection of 2DG, a drug that blocks cellular glucose utilization, and AICAR which activates AMPK, both blocked GLP-1-induced reductions in food intake. To examine the role of glucokinase, an important CNS glucose sensor, we studied glucokinase-heterozygous knockout mice, but found that they responded normally to peripherally administered GLP-1 and exendin-4. Interestingly, oral, but not i3vt or IP glucose potentiated GLP-1's anorectic action. Thus, CNS and peripheral fuel sensing are both important in GLP-1-induced reductions in food intake.

  13. GLP-1 regulation of glucagon, somatostatin and insulin in naidm patients: evidence of direct inhibition of A - cells by GLP - 1

    International Nuclear Information System (INIS)

    Naveed, A.K.; Khan, F.A.

    2006-01-01

    Glucagon-like peptide-1 (7-36) amide (GLP-1) is released from the gut into the circulation after meals and is the most potent physiological insulinotropic hormone in man. In contrast to presently available therapeutic agents for non-insulin dependent diabetes mellitus (NIDDM), GLP-1 has the advantages of both suppressing glucagon secretion and delaying gastric emptying. We report first study of subcutaneous GLP-1 treatment to determine the optimum dose required to control the NIDDM. Seven patients, with poorly controlled NIDDM were entered in the study who visited at four visits with intervals of 2-4 days and received saline, 40, 100 and 200 nmol subcutaneous GLP-1, immediately after meals. A standerdized test meal was given. A significant hypoglycaemic response (p<0.05) was achieved in patients given 40, 100 and 200 nmol GLP-1. An increase in insulin levels (p<0.05) was observed as compared to control, when 100 and 200 nmol GLP-1 was given. There was no significant difference between insulin and glucose responses when 100 and 200 nmol of GLP-1 were compared with each. The glucagon levels were significant less (p< 0.05) in patients, given 100 and 200 nmol doses as compared to control. Glucagon inhibitory response to GLP-1, when given in doses of 200 nmol was more (p< 0.05) than 100 nmol GLP-1. Somatostatin levels decreased dose dependently by GLP-1 infusions. It is concluded that suppression of glucagon secretion and inhibition of somatostatin corresponded to dose of GLP-1 used. There was no significant difference in glucose and insulin levels between 100 and 200 nmol GLP-1 doses. Therefore, present study has helped in ascertaining the optimum dose for GLP-1 i.e. 100 nmol. Down regulation of GLP-1 receptors on cells occurred at higher dose while, A and D cells inhibition occurred dose dependently. These results revealed that GLP-1 affects A and D cells directly and also through stimulation of cells. These findings will significantly contribute in the possible role

  14. Systemic colonization of potato plants by a soil-borne, GFP-tagged strain of Dickeya sp. Biovar 3

    NARCIS (Netherlands)

    Czajkowski, R.L.; Boer, de W.; Velvis, H.; Wolf, van der J.M.

    2010-01-01

    Colonization of potato plants by soilborne, green fluorescent protein (GFP)-tagged Dickeya sp. IPO2254 was investigated by selective plating, epifluorescence stereo microscopy (ESM), and confocal laser scanning microscopy (CLSM). Replicated experiments were carried out in a greenhouse using plants

  15. GLP-1-based therapies have no microvascular effects in type 2 diabetes mellitus

    NARCIS (Netherlands)

    Smits, Mark M.; Tonneijck, Lennart; Muskiet, Marcel H.A.; Hoekstra, Trynke; Kramer, Mark H.H.; Diamant, Michaela; Serné, Erik H.; Van Raalte, Daniël H.

    2016-01-01

    Objective - To assess the effects of glucagon-like peptide (GLP)-1-based therapies (ie, GLP-1 receptor agonists and dipeptidyl peptidase-4 inhibitors) on microvascular function in patients with type 2 diabetes mellitus. Approach and Results - We studied 57 patients with type 2 diabetes mellitus

  16. Liraglutide Modulates Appetite and Body Weight Via GLP-1R-Expressing Glutamatergic Neurons.

    Science.gov (United States)

    Adams, Jessica M; Pei, Hongjuan; Sandoval, Darleen A; Seeley, Randy J; Chang, Rui B; Liberles, Stephen D; Olson, David P

    2018-05-18

    Glucagon-like peptide-1 receptor (GLP-1R) agonists are FDA-approved weight loss drugs. Despite their widespread use, the sites of action through which GLP-1R agonists (GLP1RAs) impact appetite and body weight are still not fully understood. Here, we determined whether GLP-1Rs in either GABAergic or glutamatergic neurons are necessary for the acute and chronic effects of the GLP1RA liraglutide on food intake, visceral illness, body weight and neural network activation. We found that mice lacking GLP-1Rs in vGAT -expressing GABAergic neurons responded identically to controls in all parameters measured, whereas deletion of GLP-1Rs in vGlut2 -expressing glutamatergic neurons eliminated liraglutide-induced weight loss and visceral illness and severely attenuated its effects on feeding. Concomitantly, deletion of GLP-1Rs from glutamatergic neurons completely abolished the neural network activation observed after liraglutide administration. We conclude that liraglutide activates a dispersed but discrete neural network to mediate its physiological effects, and that these effects require GLP-1R expression on glutamatergic but not GABAergic neurons. © 2018 by the American Diabetes Association.

  17. Dipeptidyl peptidase-4 (DPP-4) inhibitors are favourable to glucagon-like peptide-1 (GLP-1) agonists

    DEFF Research Database (Denmark)

    Madsbad, Sten

    2012-01-01

    Incretin-based therapies, which include the GLP-1 receptor agonists and DPP-4 inhibitors, use the antidiabetic properties of potentiating the GLP-1 receptor signalling via the regulation of insulin and glucagon secretion, inhibition of gastric emptying and suppression of appetite. Most physicians...... will start antidiabetic treatment with metformin, but adding a GLP-1 receptor agonist as the second drug seems to be optimal since more patients will reach an HbA1c below 7% than with a DPP-4 inhibitor or another oral antidiabetic agents and with minimal risk of hypoglycaemia. The GLP-1 receptor agonists...

  18. GLP-1 nanomedicine alleviates gut inflammation.

    Science.gov (United States)

    Anbazhagan, Arivarasu N; Thaqi, Mentor; Priyamvada, Shubha; Jayawardena, Dulari; Kumar, Anoop; Gujral, Tarunmeet; Chatterjee, Ishita; Mugarza, Edurne; Saksena, Seema; Onyuksel, Hayat; Dudeja, Pradeep K

    2017-02-01

    The gut hormone, glucagon like peptide-1 (GLP-1) exerts anti-inflammatory effects. However, its clinical use is limited by its short half-life. Previously, we have shown that GLP-1 as a nanomedicine (GLP-1 in sterically stabilized phospholipid micelles, GLP-1-SSM) has increased in vivo stability. The current study was aimed at testing the efficacy of this GLP-1 nanomedicine in alleviating colonic inflammation and associated diarrhea in dextran sodium sulfate (DSS) induced mouse colitis model. Our results show that GLP-1-SSM treatment markedly alleviated the colitis phenotype by reducing the expression of pro-inflammatory cytokine IL-1β, increasing goblet cells and preserving intestinal epithelial architecture in colitis model. Further, GLP-1-SSM alleviated diarrhea (as assessed by luminal fluid) by increasing protein expression of intestinal chloride transporter DRA (down regulated in adenoma). Our results indicate that GLP-1 nanomedicine may act as a novel therapeutic tool in alleviating gut inflammation and associated diarrhea in inflammatory bowel disease (IBD). Published by Elsevier Inc.

  19. Potential new approaches to modifying intestinal GLP-1 secretion in patients with type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Holst, Jens Juul; McGill, Maria A

    2012-01-01

    Type 2 diabetes mellitus is associated with a progressive decline in insulin-producing pancreatic ß-cells, an increase in hepatic glucose production, and a decrease in insulin sensitivity. The incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1....... The currently available incretin-based therapies, GLP-1 receptor agonists (incretin mimetics) and dipeptidyl peptidase-4 (DPP-4) inhibitors (CD26 antigen inhibitors) [incretin enhancers], are safe and effective in the treatment of type 2 diabetes. However, they may be unable to halt the progression of type 2...... diabetes, perhaps because they do not increase secretion of endogenous GLP-1. Therapies that directly target intestinal L cells to stimulate secretion of endogenous GLP-1 could possibly prove more effective than treatment with GLP-1 receptor agonists and DPP-4 inhibitors. Potential new approaches...

  20. Obesity - an indication for GLP-1 treatment?

    DEFF Research Database (Denmark)

    Torekov, S S; Madsbad, S; Holst, Jens Juul

    2011-01-01

    Obesity is common and associated with a high rate of morbidity and mortality; therefore, treatment is of great interest. At present, bariatric surgery is the only truly successful treatment of severe obesity. Mimicking one of the effects of bariatric surgery, namely the increased secretion...... of glucagon-like peptide (GLP)-1, by artificially increasing the levels of GLP-1 might prove successful as obesity treatment. Recent studies have shown that GLP-1 is a physiological regulator of appetite and food intake. The effect on food intake and satiety is preserved in obese subjects and GLP-1 may...... therefore have a therapeutic potential. The GLP-1 analogues result in a moderate average weight loss, which is clinically relevant in relation to reducing the risk of type 2 diabetes and cardiovascular disease. Inspired by the hormone profile after gastric bypass, a future strategy in obesity drug...

  1. Treatment of antipsychotic-associated obesity with a GLP-1 receptor agonist—protocol for an investigator-initiated prospective, randomised, placebo-controlled, double-blinded intervention study: the TAO study protocol

    Science.gov (United States)

    Ishøy, Pelle L; Knop, Filip K; Broberg, Brian V; Baandrup, Lone; Fagerlund, Birgitte; Jørgensen, Niklas R; Andersen, Ulrik B; Rostrup, Egill; Glenthøj, Birte Y; Ebdrup, Bjørn H

    2014-01-01

    Introduction Antipsychotic medication is widely associated with dysmetabolism including obesity and type 2 diabetes, cardiovascular-related diseases and early death. Obesity is considered the single most important risk factor for cardiovascular morbidity and mortality. Interventions against antipsychotic-associated obesity are limited and insufficient. Glucagon-like peptide-1 (GLP-1) receptor agonists are approved for the treatment of type 2 diabetes, but their bodyweight-lowering effects have also been recognised in patients with non-diabetes. The primary endpoint of this trial is weight loss after 3 months of treatment with a GLP-1 receptor agonist (exenatide once weekly) in patients with non-diabetic schizophrenia with antipsychotic-associated obesity. Secondary endpoints include physiological and metabolic measurements, various psychopathological and cognitive measures, and structural and functional brain MRI. Methods and analysis 40 obese patients with schizophrenia or schizoaffective disorder treated with antipsychotic drugs will be randomised to subcutaneous injection of exenatide once weekly (2 mg) or placebo for 3 months, adjunctive to their antipsychotic treatment. Ethics and dissemination The trial has been approved by the Danish Health and Medicines Authority, the National Committee on Health Research Ethics and the Danish Data Protection Agency. Trial participation presupposes theoral and written patient informed consent. An external, independent monitoring committee (Good Clinical Practice Unit at Copenhagen University Hospital) will monitor the study according to the GCP Guidelines. Trial data, including positive, negative and inconclusive results, will be presented at national and international scientific meetings and conferences. Papers will be submitted to peer-reviewed journals. Trial registration ClinicalTrials.gov identifier: NCT01794429; National Committee on Health Research Ethics project number: 36378; EudraCT nr: 2012-005404-17; The

  2. GLP-1 acts on habenular avoidance circuits to control nicotine intake.

    Science.gov (United States)

    Tuesta, Luis M; Chen, Zuxin; Duncan, Alexander; Fowler, Christie D; Ishikawa, Masago; Lee, Brian R; Liu, Xin-An; Lu, Qun; Cameron, Michael; Hayes, Matthew R; Kamenecka, Theodore M; Pletcher, Matthew; Kenny, Paul J

    2017-05-01

    Tobacco smokers titrate their nicotine intake to avoid its noxious effects, sensitivity to which may influence vulnerability to tobacco dependence, yet mechanisms of nicotine avoidance are poorly understood. Here we show that nicotine activates glucagon-like peptide-1 (GLP-1) neurons in the nucleus tractus solitarius (NTS). The antidiabetic drugs sitagliptin and exenatide, which inhibit GLP-1 breakdown and stimulate GLP-1 receptors, respectively, decreased nicotine intake in mice. Chemogenetic activation of GLP-1 neurons in NTS similarly decreased nicotine intake. Conversely, Glp1r knockout mice consumed greater quantities of nicotine than wild-type mice. Using optogenetic stimulation, we show that GLP-1 excites medial habenular (MHb) projections to the interpeduncular nucleus (IPN). Activation of GLP-1 receptors in the MHb-IPN circuit abolished nicotine reward and decreased nicotine intake, whereas their knockdown or pharmacological blockade increased intake. GLP-1 neurons may therefore serve as 'satiety sensors' for nicotine that stimulate habenular systems to promote nicotine avoidance before its aversive effects are encountered.

  3. Carboxy-terminal truncation activates glp-1 protein to specify vulval fates in Caenorhabditis elegans.

    Science.gov (United States)

    Mango, S E; Maine, E M; Kimble, J

    1991-08-29

    The glp-1 and lin-12 genes encode homologous transmembrane proteins that may act as receptors for cell interactions during development. The glp-1 product is required for induction of germ-line proliferation and for embryogenesis. By contrast, lin-12 mediates somatic cell interactions, including those between the precursor cells that form the vulval hypodermis (VPCs). Here we analyse an unusual allele of glp-1, glp-1(q35), which displays a semidominant multivulva phenotype (Muv), as well as the typical recessive, loss-of-function Glp phenotypes (sterility and embryonic lethality). We find that the effects of glp-1(q35) on VPC development mimic those of dominant lin-12 mutations, even in the absence of lin-12 activity. The glp-1(q35) gene bears a nonsense mutation predicted to eliminate the 122 C-terminal amino acids, including a ProGluSerThr (PEST) sequence thought to destabilize proteins. We suggest that the carboxy terminus bears a negative regulatory domain which normally inactivates glp-1 in the VPCs. We propose that inappropriate glp-1(q35) activity can substitute for lin-12 to determine vulval fate, perhaps by driving the VPCs to proliferate.

  4. Distinct regions in the C-Terminus required for GLP-1R cell surface expression, activity and internalisation.

    Science.gov (United States)

    Thompson, Aiysha; Kanamarlapudi, Venkateswarlu

    2015-09-15

    The glucagon-like peptide-1 (GLP-1) receptor (GLP-1R), an important drug target in the treatment of type 2 diabetes, is a G-protein coupled receptor (GPCR) that mediates insulin secretion by GLP-1. The N-terminus controls GLP-1R biosynthetic trafficking to the cell surface but the C-terminus involvement in that trafficking is unknown. The aim of this study was to identify distinct regions within the C-terminal domain required for human GLP-1R (hGLP-1R) cell surface expression, activity and internalisation using a number of C-terminal deletions and site-directed mutations. The results of this study revealed that the residues 411-418 within the C-terminal domain of the hGLP-1R are critical in targeting the newly synthesised receptor to the plasma membrane. The residues 419-430 are important for cAMP producing activity of the receptor, most likely by coupling to Gαs. However, the residues 431-450 within the C-terminus are essential for agonist-induced hGLP-1R internalisation. In conclusion, these findings demonstrate the hGLP-1R has distinct regions within the C-terminal domain required for its cell surface expression, activity and agonist-induced internalisation. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  5. Protective effects of GLP-1 analogues exendin-4 and GLP-1(9-36) amide against ischemia-reperfusion injury in rat heart

    DEFF Research Database (Denmark)

    Sonne, David P; Engstrøm, Thomas; Treiman, Marek

    2007-01-01

    to exert cardiovascular effects in a number of experimental models. Here we tested exendin-4 (Exe-4), a peptide agonist at GLP-1 receptors, and GLP-1(9-36) amide, the primary endogenous metabolite of GLP-1 (both in the concentration range 0.03-3.0 nM), for their protective effects against ischemia......-reperfusion injury (IRI) in an isolated rat heart preparation. When administered, the agents were only present for the first 15 min of a 120 min reperfusion period (postconditioning protocol). Exe-4, but not GLP-1(9-36) amide, showed a strong infarct-limiting action (from 33.2% +/-2.7% to 14.5% +/-2.......2% of the ischemic area, pamide were able to augment left ventricular performance (left ventricular developed pressure and rate-pressure product) during...

  6. GLP-1 suppresses gastrointestinal motility and inhibits the migrating motor complex in healthy subjects and patients with irritable bowel syndrome

    DEFF Research Database (Denmark)

    Hellström, P M; Näslund, E; Edholm, T

    2008-01-01

    hormones, and gut tissue expression of GLP-1 receptor was studied. In healthy subjects, GLP-1 0.7 pmol kg(-1) min(-1) reduced the migrating motor complexes (MMCs) from a median of 2 (range 2-3) to 0.5 (0-2), and motility index from 4.9 +/- 0.1 to 4.3 +/- 0.3 ln Sigma(mmHg*s min(-1)) in jejunum, while GLP-1...

  7. Long-Term Treatment with Liraglutide, a Glucagon-Like Peptide-1 (GLP-1 Receptor Agonist, Has No Effect on β-Amyloid Plaque Load in Two Transgenic APP/PS1 Mouse Models of Alzheimer's Disease.

    Directory of Open Access Journals (Sweden)

    Henrik H Hansen

    Full Text Available One of the major histopathological hallmarks of Alzheimer's disease (AD is cerebral deposits of extracellular β-amyloid peptides. Preclinical studies have pointed to glucagon-like peptide 1 (GLP-1 receptors as a potential novel target in the treatment of AD. GLP-1 receptor agonists, including exendin-4 and liraglutide, have been shown to promote plaque-lowering and mnemonic effects of in a number of experimental models of AD. Transgenic mouse models carrying genetic mutations of amyloid protein precursor (APP and presenilin-1 (PS1 are commonly used to assess the pharmacodynamics of potential amyloidosis-lowering and pro-cognitive compounds. In this study, effects of long-term liraglutide treatment were therefore determined in two double APP/PS1 transgenic mouse models of Alzheimer's disease carrying different clinical APP/PS1 mutations, i.e. the 'London' (hAPPLon/PS1A246E and 'Swedish' mutation variant (hAPPSwe/PS1ΔE9 of APP, with co-expression of distinct PS1 variants. Liraglutide was administered in 5 month-old hAPPLon/PS1A246E mice for 3 months (100 or 500 ng/kg/day, s.c., or 7 month-old hAPPSwe/PS1ΔE9 mice for 5 months (500 ng/kg/day, s.c.. In both models, regional plaque load was quantified throughout the brain using stereological methods. Vehicle-dosed hAPPSwe/PS1ΔE9 mice exhibited considerably higher cerebral plaque load than hAPPLon/PS1A246E control mice. Compared to vehicle-dosed transgenic controls, liraglutide treatment had no effect on the plaque levels in hAPPLon/PS1A246E and hAPPSwe/PS1ΔE9 mice. In conclusion, long-term liraglutide treatment exhibited no effect on cerebral plaque load in two transgenic mouse models of low- and high-grade amyloidosis, which suggests differential sensitivity to long-term liraglutide treatment in various transgenic mouse models mimicking distinct pathological hallmarks of AD.

  8. SGLT2 inhibitors or GLP-1 receptor agonists as second-line therapy in type 2 diabetes: patient selection and perspectives.

    Science.gov (United States)

    Gurgle, Holly E; White, Karen; McAdam-Marx, Carrie

    2016-01-01

    Controversy exists regarding the selection of second-line therapy for patients with type 2 diabetes mellitus (T2DM) who are unable to achieve glycemic control with metformin therapy alone. Newer pharmacologic treatments for T2DM include glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter 2 inhibitors. Both the classes of medication are efficacious, exhibit positive effects on weight, and are associated with minimal risk of hypoglycemia. The purpose of this review is to compare the clinical trial and real-world effectiveness data of glucagon-like peptide-1 receptor agonists versus sodium-glucose cotransporter 2 inhibitors related to A1c reduction, weight loss, cost-effectiveness, cardiovascular outcomes, and safety in patients with T2DM. This review summarizes comparative evidence for providers who are determining which of the two classes may be the most appropriate for a specific patient.

  9. Gastric myoelectric activity during cisplatin-induced acute and delayed emesis reveals a temporal impairment of slow waves in ferrets: effects not reversed by the GLP-1 receptor antagonist, exendin (9-39).

    Science.gov (United States)

    Lu, Zengbing; Ngan, Man P; Lin, Ge; Yew, David T W; Fan, Xiaodan; Andrews, Paul L R; Rudd, John A

    2017-11-17

    Preclinical studies show that the glucagon-like peptide-1 (GLP-1) receptor antagonist, exendin (9-39), can reduce acute emesis induced by cisplatin. In the present study, we investigate the effect of exendin (9-39) (100 nmol/24 h, i.c.v), on cisplatin (5 mg/kg, i.p.)-induced acute and delayed emesis and changes indicative of 'nausea' in ferrets. Cisplatin induced 37.2 ± 2.3 and 59.0 ± 7.7 retches + vomits during the 0-24 (acute) and 24-72 h (delayed) periods, respectively. Cisplatin also increased ( P Advanced multifractal detrended fluctuation analysis revealed that the slow wave signal shape became more simplistic during delayed emesis. Cisplatin did not affect blood pressure (BP), but transiently increased heart rate, and decreased heart rate variability (HRV) during acute emesis; HRV spectral analysis indicated a shift to 'sympathetic dominance'. A hyperthermic response was seen during acute emesis, but hypothermia occurred during delayed emesis and there was also a decrease in HR. Exendin (9-39) did not improve feeding and drinking but reduced cisplatin-induced acute emesis by ~59 % ( P waves may represent a novel approach to treat the side effects of chemotherapy.

  10. A surface plasmon resonance assay for characterisation and epitope mapping of anti-GLP-1 antibodies.

    Science.gov (United States)

    Thomsen, Lasse; Gurevich, Leonid

    2018-04-19

    The incretin hormone glucagon-like peptide-1 (GLP-1) has been subject to substantial pharmaceutical research regarding the treatment of type 2 diabetes mellitus. However, quantification of GLP-1 levels remains complicated due to the low circulation concentration and concurrent existence of numerous metabolites, homologous peptides, and potentially introduced GLP-1 receptor agonists. Surface plasmon resonance (SPR) facilitates real-time monitoring allowing a more detailed characterisation of the interaction compared with conventional enzyme-linked immunosorbent assays (ELISA). In this paper, we describe the development of the first SPR assays for characterisation of anti-GLP-1 antibodies for ELISA purposes. Binding responses were obtained on covalently immobilised anti-GLP-1 antibodies at 12°C, 25°C, and 40°C and fitted to a biomolecular (1:1) interaction model showing association rates of 1.01 × 10 3 to 4.54 × 10 3  M -1  s -1 and dissociation rates of 3.56 × 10 -5 to 1.56 × 10 -3  s -1 leading to affinities of 35.2 to 344 nM, depending on the temperature. Determination of thermodynamic properties revealed an enthalpy driven interaction (ΔH polar amino acids (ΔC p  < 0). Pair-wise epitope mapping was performed on captured anti-GLP-1 antibodies followed by subsequent interaction with GLP-1 (7-36) and other anti-GLP-1 antibodies. A global evaluation of every binding response led to an epitope map elucidating the potential of various anti-GLP-1 antibody pairs for sandwich ELISA and hence pinpointing the optimal antibody combinations. The SPR assays proved capable of providing vital information for ELISA development endorsing it as a useful optimisation tool. Copyright © 2018 John Wiley & Sons, Ltd.

  11. Endogenous GLP-1 in lateral septum contributes to stress-induced hypophagia.

    Science.gov (United States)

    Terrill, Sarah J; Maske, Calyn B; Williams, Diana L

    2018-03-03

    Glucagon-like peptide 1 (GLP-1) neurons of the caudal brainstem project to many brain areas, including the lateral septum (LS), which has a known role in stress responses. Previously, we showed that endogenous GLP-1 in the LS plays a physiologic role in the control of feeding under non-stressed conditions, however, central GLP-1 is also involved in behavioral and endocrine responses to stress. Here, we asked whether LS GLP-1 receptors (GLP-1R) contribute to stress-induced hypophagia. Male rats were implanted with bilateral cannulas targeting the dorsal subregion of the LS (dLS). In a within-subjects design, shortly before the onset of the dark phase, rats received dLS injections of saline or the GLP-1R antagonist Exendin (9-39) (Ex9) prior to 30 min restraint stress. Food intake was measured continuously for the next 20 h. The stress-induced hypophagia observed within the first 30 min of dark was not influenced by Ex9 pretreatment, but Ex9 tended to blunt the effect of stress as early as 1 and 2 h into the dark phase. By 4-6 h, there were significant stress X drug interactions, and Ex9 pretreatment blocked the stress-induced suppression of feeding. These effects were mediated entirely through changes in average meal size; stress suppressed meal size while dLS Ex9 attenuated this effect. Using a similar design, we examined the role of dLS GLP-1R in the neuroendocrine response to acute restraint stress. As expected, stress potently increased serum corticosterone, but blockade of dLS GLP-1Rs did not affect this response. Together, these data show that endogenous GLP-1 action in the dLS plays a role in some but not all of the physiologic responses to acute stress. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. Modulation of taste sensitivity by GLP-1 signaling in taste buds.

    Science.gov (United States)

    Martin, Bronwen; Dotson, Cedrick D; Shin, Yu-Kyong; Ji, Sunggoan; Drucker, Daniel J; Maudsley, Stuart; Munger, Steven D

    2009-07-01

    Modulation of sensory function can help animals adjust to a changing external and internal environment. Even so, mechanisms for modulating taste sensitivity are poorly understood. Using immunohistochemical, biochemical, and behavioral approaches, we found that the peptide hormone glucagon-like peptide-1 (GLP-1) and its receptor (GLP-1R) are expressed in mammalian taste buds. Furthermore, we found that GLP-1 signaling plays an important role in the modulation of taste sensitivity: GLP-1R knockout mice exhibit a dramatic reduction in sweet taste sensitivity as well as an enhanced sensitivity to umami-tasting stimuli. Together, these findings suggest a novel paracrine mechanism for the hormonal modulation of taste function in mammals.

  13. Enteroendocrine L Cells Sense LPS after Gut Barrier Injury to Enhance GLP-1 Secretion

    Directory of Open Access Journals (Sweden)

    Lorène J. Lebrun

    2017-10-01

    Full Text Available Summary: Glucagon-like peptide 1 (GLP-1 is a hormone released from enteroendocrine L cells. Although first described as a glucoregulatory incretin hormone, GLP-1 also suppresses inflammation and promotes mucosal integrity. Here, we demonstrate that plasma GLP-1 levels are rapidly increased by lipopolysaccharide (LPS administration in mice via a Toll-like receptor 4 (TLR4-dependent mechanism. Experimental manipulation of gut barrier integrity after dextran sodium sulfate treatment, or via ischemia/reperfusion experiments in mice, triggered a rapid rise in circulating GLP-1. This phenomenon was detected prior to measurable changes in inflammatory status and plasma cytokine and LPS levels. In human subjects, LPS administration also induced GLP-1 secretion. Furthermore, GLP-1 levels were rapidly increased following the induction of ischemia in the human intestine. These findings expand traditional concepts of enteroendocrine L cell biology to encompass the sensing of inflammatory stimuli and compromised mucosal integrity, linking glucagon-like peptide secretion to gut inflammation. : Lebrun et al. demonstrate that enteroendocrine L cells sense lipopolysaccharides (pro-inflammatory bacterial compounds after gut injury and respond by secreting glucagon-like peptide 1. These findings expand concepts of L cell function to include roles as both a nutrient and pathogen sensor, linking glucagon-like peptide secretion to gut inflammation. Keywords: glucagon-like peptide 1, lipopolysaccharides, enteroendocrine cells, TLR4, gut injury, intestinal ischemia, inflammation

  14. Glucagon-related peptide 1 (GLP-1): hormone and neurotransmitter

    DEFF Research Database (Denmark)

    Larsen, Philip J; Holst, Jens Juul

    2005-01-01

    normal and pathophysiological role of GLP-1 have been published over the last two decades and our understanding of GLP-1 action has widened considerably. In the present review, we have tried to cover our current understanding of GLP-1 actions both as a peripheral hormone and as a central neurotransmitter...

  15. Inflammation meets metabolic disease: Gut feeling mediated by GLP-1

    Directory of Open Access Journals (Sweden)

    Tamara eZietek

    2016-04-01

    Full Text Available Chronic diseases such as obesity and diabetes, cardiovascular and inflammatory bowel diseases (IBD share common features in their pathology. Metabolic disorders exhibit strong inflammatory underpinnings and vice versa, inflammation is associated with metabolic alterations. Next to cytokines and cellular stress pathways like the unfolded protein response (UPR, alterations in the enteroendocrine system are intersections of various pathologies. Enteroendocrine cells (EEC have been studied extensively for their ability to regulate gastrointestinal motility, secretion, and insulin release by release of peptide hormones. In particular the L cell-derived incretin hormone glucagon-like peptide 1 (GLP-1 has gained enormous attention due to its insulinotropic action and relevance in the treatment of type 2 diabetes (T2D. Yet, accumulating data indicates a critical role for EEC and in particular for GLP-1 in metabolic adaptation and in orchestrating immune responses beyond blood glucose control. EEC sense the lamina propria and luminal environment including the microbiota via receptors and transporters. Subsequently mediating signals by secreting hormones and cytokines, EEC can be considered as integrators of metabolic and inflammatory signaling.This review focuses on L cell and GLP-1 functions in the context of metabolic and inflammatory diseases. The effects of incretin-based therapies on metabolism and immune system are discussed and the interrelation and common features of metabolic and immune-mediated disorders are highlighted. Moreover, it presents data on the impact of inflammation, in particular of IBD on EEC and discusses the potential role of the microbiota as link between nutrients, metabolism, immunity and disease.

  16. In vitro antagonistic activity and the protective effect of probiotic Bacillus licheniformis Dahb1 in zebrafish challenged with GFP tagged Vibrio parahaemolyticus Dahv2.

    Science.gov (United States)

    Girija, Vairavan; Malaikozhundan, Balasubramanian; Vaseeharan, Baskaralingam; Vijayakumar, Sekar; Gobi, Narayanan; Del Valle Herrera, Marian; Chen, Jiann-Chu; Santhanam, Perumal

    2018-01-01

    In vitro antagonistic activity and the protective effect of probiotic Bacillus licheniformis Dahb1 in zebrafish (Danio rerio) challenged with GFP tagged Vibrio parahaemolyticus Dahv2 was studied. The cell free extract of probiotic B. licheniformis Dahb1 at 100 μg mL -1 showed growth inhibition of V. parahaemolyticus Dahv2 in vitro. B. licheniformis Dahb1 also inhibited the biofilm growth of GFP tagged V. parahaemolyticus Dahv2 at 100 μg mL -1 in vitro. The growth and survival of zebrafish was tested using probiotic B. licheniformis Dahb1. Weight (1.28 g) of zebrafish that received the cell free extract was much higher than in control (1.04 g). The mortality of zebrafish infected with GFP tagged V. parahaemolyticus Dahv2 at 10 7 Cfu mL -1 (Group IV) was 100%, whereas a complete survival of zebrafish that received the cell free extract of B. licheniformis Dahb1 at 10 7 Cfu mL -1 (Group VII) was observed after 30 days. The number of GFP tagged V. parahaemolyticus Dahv2 colonies in the intestine and gills significantly reduced after treatment with the cell free extract of B. licheniformis Dahb1. Furthermore, a significant decrease in the fluorescent colonies of GFP tagged V. parahaemolyticus Dahv2 was observed after treatment with the cell free extract of B. licheniformis Dahb1 under confocal laser scanning microscopy (CLSM). In conclusion, the cell free extract of B. licheniformis Dahb1 could prevent Vibrio infection by enhancing the growth and survival of zebrafish. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. The Dietary Furocoumarin Imperatorin Increases Plasma GLP-1 Levels in Type 1-Like Diabetic Rats

    Directory of Open Access Journals (Sweden)

    Lin-Yu Wang

    2017-10-01

    Full Text Available Imperatorin, a dietary furocoumarin, is found not only in medicinal plants, but also in popular culinary herbs, such as parsley and fennel. Recently, imperatorin has been shown to activate GPR119 in cells. Another GPR, GPR131, also called TGR5 or G-protein-coupled bile acid receptor 1 (GPBAR1, is known to regulate glucose metabolism. Additionally, TGR5 activation increases glucagon-like peptide (GLP-1 secretion to lower blood sugar levels in animals. Therefore, the present study aims to determine whether the effects of imperatorin on GLP-1 secretion are mediated by TGR5. First, we transfected cultured Chinese hamster ovary cells (CHO-K1 cells with the TGR5 gene. Glucose uptake was confirmed in the transfected cells using a fluorescent indicator. Moreover, NCI-H716 cells, which secrete GLP-1, were used to investigate the changes in calcium concentrations and GLP-1 levels. In addition, streptozotocin (STZ-induced type 1-like diabetic rats were used to identify the effects of imperatorin in vivo. Imperatorin dose-dependently increased glucose uptake in CHO-K1 cells expressing TGR5. In STZ diabetic rats, similar to the results in NCI-H716 cells, imperatorin induced a marked increase of GLP-1 secretion that was reduced, but not totally abolished, by a dose of triamterene that inhibited TGR5. Moreover, increases in GLP-1 secretion induced by imperatorin and GPR119 activation were shown in NCI-H716 cells. We demonstrated that imperatorin induced GLP-1 secretion via activating TGR5 and GPR119. Therefore, imperatorin shall be considered as a TGR5 and GPR119 agonist.

  18. Recombinant human GLP-1(rhGLP-1) alleviating renal tubulointestitial injury in diabetic STZ-induced rats.

    Science.gov (United States)

    Yin, Weiqin; Xu, Shiqing; Wang, Zai; Liu, Honglin; Peng, Liang; Fang, Qing; Deng, Tingting; Zhang, Wenjian; Lou, Jinning

    2018-01-01

    GLP-1-based treatment improves glycemia through stimulation of insulin secretion and inhibition of glucagon secretion. Recently, more and more findings showed that GLP-1 could also protect kidney from diabetic nephropathy. Most of these studies focused on glomeruli, but the effect of GLP-1 on tubulointerstitial and tubule is not clear yet. In this study, we examined the renoprotective effect of recombinant human GLP-1 (rhGLP-1), and investigated the influence of GLP-1 on inflammation and tubulointerstitial injury using diabetic nephropathy rats model of STZ-induced. The results showed that rhGLP-1 reduced urinary albumin without influencing the body weight and food intake. rhGLP-1 could increased the serum C-peptide slightly but not lower fasting blood glucose significantly. In diabetic nephropathy rats, beside glomerular sclerosis, tubulointerstitial fibrosis was very serious. These lesions could be alleviated by rhGLP-1. rhGLP-1 decreased the expression of profibrotic factors collagen I, α-SMA, fibronectin, and inflammation factors MCP-1 and TNFα in tubular tissue and human proximal tubular cells (HK-2 cells). Furthermore, rhGLP-1 significantly inhibited the phosphorylation of NF-κB, MAPK in both diabetic tubular tissue and HK-2 cells. The inhibition of the expression of TNFα, MCP-1, collagen I and α-SMA in HK-2 cells by GLP-1 could be mimicked by blocking NF-κB or MAPK. These results indicate that rhGLP-1 exhibit renoprotective effect by alleviation of tubulointerstitial injury via inhibiting phosphorylation of MAPK and NF-κB. Therefore, rhGLP-1 may be a potential drug for treatment of diabetic nephropathy. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. GFP tagged Vibrio parahaemolyticus Dahv2 infection and the protective effects of the probiotic Bacillus licheniformis Dahb1 on the growth, immune and antioxidant responses in Pangasius hypophthalmus.

    Science.gov (United States)

    Gobi, Narayanan; Malaikozhundan, Balasubramanian; Sekar, Vijayakumar; Shanthi, Sathappan; Vaseeharan, Baskaralingam; Jayakumar, Rengarajan; Khudus Nazar, Abdul

    2016-05-01

    In this study, the pathogenicity of GFP tagged Vibrio parahaemolyticus Dahv2 and the protective effect of the probiotic strain, Bacillus licheniformis Dahb1 was studied on the Asian catfish, Pangasius hypophthalmus. The experiment was carried out for 24 days with three groups and one group served as the control (without treatment). In the first group, P. hypophthalmus was orally infected with 1 mL of GFP tagged V. parahaemolyticus Dahv2 at two different doses (10(5) and 10(7) cfu mL(-1)). In the second group, P. hypophthalmus was orally administrated with 1 ml of the probiotic B. licheniformis Dahb1 at two different doses (10(5) and 10(7) cfu mL(-1)). In the third group, P. hypophthalmus was orally infected first with 1 mL of GFP tagged V. parahaemolyticus Dahv2 followed by the administration of 1 mL of B. licheniformis Dahb1 (combined treatment) at two different doses (10(5) and 10(7) cfu mL(-1)). The growth, immune (myeloperoxidase, respiratory burst, natural complement haemolytic and lysozyme activity) and antioxidant (glutathione-S-transferase, reduced glutathione and total glutathione) responses of P. hypophthalmus were reduced after post infection of GFP tagged V. parahaemolyticus Dahv2 compared to control. However, after administration with the probiotic B. licheniformis Dahb1 at 10(5) cfu mL(-1), P. hypophthalmus showed significant increase in the growth, immune and antioxidant responses compared to 10(7) cfu mL(-1). On the otherhand, the growth, immune and antioxidant responses of P. hypophthalmus infected and administrated with combined GFP tagged Vibrio + Bacillus at 10(5) cfu mL(-1) were relatively higher than that of GFP tagged V. parahaemolyticus Dahv2 and control groups but lower than that of probiotic B. licheniformis Dahb1 groups. The results of the present study conclude that the probiotic B. licheniformis Dahb1 at 10(5) cfu mL(-1) has the potential to protect the P. hypophthalmus against V. parahaemolyticus Dahv2 infection by enhancing the growth

  20. The role of somatostatin in GLP-1-induced inhibition of glucagon secretion in mice

    DEFF Research Database (Denmark)

    Ørgaard, Anne; Holst, Jens J

    2017-01-01

    AIMS/HYPOTHESIS: Glucagon-like peptide-1 (GLP-1) receptor agonists are currently used for the treatment of type 2 diabetes. Their main mechanism of action is enhancement of glucose-induced insulin secretion (from increased beta cell glucose sensitivity) and inhibition of glucagon secretion...... on glucagon secretion is heavily debated. Glucagon inhibition is also said to be glucose-dependent, although it is unclear what is meant by this. We hypothesise here that GLP-1 does not inhibit glucagon secretion during hypoglycaemia because the inhibition depends on somatostatin secretion, which in turn...

  1. On the physiology of GIP and GLP-1

    DEFF Research Database (Denmark)

    Holst, Jens Juul

    2005-01-01

    circulation. Apparently, before it is degraded, GLP-1 activates sensory afferents in the gastrointestinal mucosa with cell bodies in the nodose ganglion, signaling onwards to the brain stem and the hypothalamus. A similar mechanism seems to be involved in GLP-1's effect on gastrointestinal motility...... and secretion, and perhaps its actions on appetite and food intake, all of which may be even more physiologically important than its effects on the beta cells. Cardiovascular and neuroprotective actions of GLP-1 have also recently been reported. Regarding GIP, several lines of evidence suggest that GIP......Recent studies have indicated that GIP and GLP-1 are about as important as each other in the incretin effect, being released rapidly after meals and being active already at fasting glucose levels. Although the density of GLP-1 producing cells is higher distally, GlP-1 is normally secreted...

  2. Gq and Gs signaling acting in synergy to control GLP-1 secretion

    DEFF Research Database (Denmark)

    Pedersen, Maria Hauge; Ekberg, Jeppe Hvidtfeldt; Engelstoft, Maja Storm

    2017-01-01

    GPR40 is generally known to signal through Gq. However, in transfected cells, certain synthetic agonists can make the receptor signal also through Gs and cAMP (Hauge et al., 2015). Here we find that, in colonic crypt cultures, the GLP-1 secretion induced by such Gq + Gs GPR40 agonists is indeed i...

  3. 18F-radiolabeled analogs of exendin-4 for PET imaging of GLP-1 in insulinoma

    International Nuclear Information System (INIS)

    Kiesewetter, Dale O.; Ma, Ying; Niu, Gang; Quan, Qimeng; Guo, Ning; Chen, Xiaoyuan; Gao, Haokao

    2012-01-01

    Glucagon-like peptide type 1 (GLP-1) is an incretin peptide that augments glucose-stimulated insulin release following oral consumption of nutrients. Its message is transmitted via a G protein-coupled receptor called GLP-1R, which is colocalized with pancreatic β-cells. The GLP-1 system is responsible for enhancing insulin release, inhibiting glucagon production, inhibiting hepatic gluconeogenesis, inhibiting gastric mobility, and suppression of appetite. The abundance of GLP-1R in pancreatic β-cells in insulinoma, a cancer of the pancreas, and the activity of GLP-1 in the cardiovascular system have made GLP-1R a target for molecular imaging. We prepared 18 F radioligands for GLP-1R by the reaction of [ 18 F]FBEM, a maleimide prosthetic group, with [Cys 0 ] and [Cys 40 ] analogs of exendin-4. The binding affinity, cellular uptake and internalization, in vitro stability, and uptake and specificity of uptake of the resulting compounds were determined in an INS-1 xenograft model in nude mice. The [ 18 F]FBEM-[Cys x ]-exendin-4 analogs were obtained in good yield (34.3 ± 3.4%, n = 11), based on the starting compound [ 18 F]FBEM, and had a specific activity of 45.51 ± 16.28 GBq/μmol (1.23 ± 0.44 Ci/μmol, n = 7) at the end of synthesis. The C-terminal isomer, [ 18 F]FBEM-[Cys 40 ]-exendin-4, had higher affinity for INS-1 tumor cells (IC 50 1.11 ± 0.057 nM) and higher tumor uptake (25.25 ± 3.39 %ID/g at 1 h) than the N-terminal isomer, [ 18 F]FBEM-[Cys 0 ]-exendin-4 (IC 50 2.99 ± 0.06 nM, uptake 7.20 ± 1.26 %ID/g at 1 h). Uptake of both isomers into INS-1 tumor, pancreas, stomach, and lung could be blocked by preinjection of nonradiolabeled [Cys x ]-exendin-4 (p 18 F]FBEM-[Cys 40 ]-exendin-4 and [ 18 F]FBEM-[Cys 0 ]-exendin-4 have high affinity for GLP-1R and display similar in vitro cell internalization. The higher uptake into INS-1 xenograft tumors exhibited by [ 18 F]FBEM-[Cys 40 ]-exendin-4 suggests that this compound would be the better tracer for imaging

  4. 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

  5. Prediction of thyroid C-cell carcinogenicity after chronic administration of GLP1-R agonists in rodents

    Energy Technology Data Exchange (ETDEWEB)

    Brink, Willem van den; Emerenciana, Annette [Systems Pharmacology, Division of Pharmacology, Leiden Academic Centre for Drug Research, Leiden University, Leiden (Netherlands); Medicines Evaluation Board, Utrecht (Netherlands); Bellanti, Francesco [Systems Pharmacology, Division of Pharmacology, Leiden Academic Centre for Drug Research, Leiden University, Leiden (Netherlands); Della Pasqua, Oscar [Systems Pharmacology, Division of Pharmacology, Leiden Academic Centre for Drug Research, Leiden University, Leiden (Netherlands); Clinical Pharmacology Modelling & Simulation, GlaxoSmithKline, Stockley Park, Uxbridge (United Kingdom); Clinical Pharmacology & Therapeutics, UCL, School of Life and Medical Sciences, London (United Kingdom); Laan, Jan Willem van der, E-mail: jw.vd.laan@cbg-meb.nl [Division of Toxicology, Leiden Academic Centre for Drug Research, Leiden University, Leiden (Netherlands); Medicines Evaluation Board, Utrecht (Netherlands)

    2017-04-01

    Increased incidence of C-cell carcinogenicity has been observed for glucagon-like-protein-1 receptor (GLP-1r) agonists in rodents. It is suggested that the duration of exposure is an indicator of carcinogenic potential in rodents of the different products on the market. Furthermore, the role of GLP-1-related mechanisms in the induction of C-cell carcinogenicity has gained increased attention by regulatory agencies. This study proposes an integrative pharmacokinetic/pharmacodynamic (PKPD) framework to identify explanatory factors and characterize differences in carcinogenic potential of the GLP-1r agonist products. PK models for four products (exenatide QW (once weekly), exenatide BID (twice daily), liraglutide and lixisenatide) were developed using nonlinear mixed effects modelling. Predicted exposure was subsequently linked to GLP-1r stimulation using in vitro GLP-1r potency data. A logistic regression model was then applied to exenatide QW and liraglutide data to assess the relationship between GLP-1r stimulation and thyroid C-cell hyperplasia incidence as pre-neoplastic predictor of a carcinogenic response. The model showed a significant association between predicted GLP-1r stimulation and C-cell hyperplasia after 2 years of treatment. The predictive performance of the model was evaluated using lixisenatide, for which hyperplasia data were accurately described during the validation step. The use of a model-based approach provided insight into the relationship between C-cell hyperplasia and GLP-1r stimulation for all four products, which is not possible with traditional data analysis methods. It can be concluded that both pharmacokinetics (exposure) and pharmacodynamics (potency for GLP-1r) factors determine C-cell hyperplasia incidence in rodents. Our work highlights the pharmacological basis for GLP-1r agonist-induced C-cell carcinogenicity. The concept is promising for application to other drug classes. - Highlights: • An integrative PKPD model is applied to

  6. Prediction of thyroid C-cell carcinogenicity after chronic administration of GLP1-R agonists in rodents

    International Nuclear Information System (INIS)

    Brink, Willem van den; Emerenciana, Annette; Bellanti, Francesco; Della Pasqua, Oscar; Laan, Jan Willem van der

    2017-01-01

    Increased incidence of C-cell carcinogenicity has been observed for glucagon-like-protein-1 receptor (GLP-1r) agonists in rodents. It is suggested that the duration of exposure is an indicator of carcinogenic potential in rodents of the different products on the market. Furthermore, the role of GLP-1-related mechanisms in the induction of C-cell carcinogenicity has gained increased attention by regulatory agencies. This study proposes an integrative pharmacokinetic/pharmacodynamic (PKPD) framework to identify explanatory factors and characterize differences in carcinogenic potential of the GLP-1r agonist products. PK models for four products (exenatide QW (once weekly), exenatide BID (twice daily), liraglutide and lixisenatide) were developed using nonlinear mixed effects modelling. Predicted exposure was subsequently linked to GLP-1r stimulation using in vitro GLP-1r potency data. A logistic regression model was then applied to exenatide QW and liraglutide data to assess the relationship between GLP-1r stimulation and thyroid C-cell hyperplasia incidence as pre-neoplastic predictor of a carcinogenic response. The model showed a significant association between predicted GLP-1r stimulation and C-cell hyperplasia after 2 years of treatment. The predictive performance of the model was evaluated using lixisenatide, for which hyperplasia data were accurately described during the validation step. The use of a model-based approach provided insight into the relationship between C-cell hyperplasia and GLP-1r stimulation for all four products, which is not possible with traditional data analysis methods. It can be concluded that both pharmacokinetics (exposure) and pharmacodynamics (potency for GLP-1r) factors determine C-cell hyperplasia incidence in rodents. Our work highlights the pharmacological basis for GLP-1r agonist-induced C-cell carcinogenicity. The concept is promising for application to other drug classes. - Highlights: • An integrative PKPD model is applied to

  7. Specificity and sensitivity of commercially available assays for glucagon-like peptide-1 (GLP-1)

    DEFF Research Database (Denmark)

    Bak, Monika Judyta; Albrechtsen, Nicolai Jacob Wewer; Pedersen, Jens

    2014-01-01

    assessed with 3 commercial kits. RESULTS: The USCN LIFE assay detected none of the GLP-1 isoforms. The active GLP-1 ELISAs from Millipore and DRG seemed identical and were specific for intact GLP-1 in buffer and plasma. The Meso Scale Discovery Total GLP-1 kit detected all six GLP-1 isoforms, although...

  8. Treatment of type 1 diabetic patients with glucagon-like peptide-1 (GLP-1) and GLP-1R agonists

    DEFF Research Database (Denmark)

    Kielgast, Urd; Holst, Jens Juul; Madsbad, Sten

    2009-01-01

    for a beta-cell preserving effect. This review summarizes the present knowledge of GLP-1 and its analogues regarding its role as a possible treatment in patients with type 1 diabetes. The studies that address the effect of GLP-1 and GLP-1 analogues on beta-cell mass in both type 2 and type 1 diabetes......, as well as the potential of GLP-1 as an adjuvant therapy in islet cell transplantation, will be reviewed. Suggestions for future studies of GLP-1 treatment in type 1 diabetes may include early treatment in order to preserve beta-cell mass and prolong the remission period, but should also take a potential...... appetite and bodyweight in obese subjects. In vivo studies using animal models of type 2 diabetes and in vitro studies using human islet cells have suggested that GLP-1 or GLP-1 analogues are also able to increase beta-cell mass, but in animal models of type 1 diabetes, there is much less evidence...

  9. Sitagliptin reduces cardiac apoptosis, hypertrophy and fibrosis primarily by insulin-dependent mechanisms in experimental type-II diabetes. Potential roles of GLP-1 isoforms.

    Directory of Open Access Journals (Sweden)

    Belén Picatoste

    Full Text Available BACKGROUND: Myocardial fibrosis is a key process in diabetic cardiomyopathy. However, their underlying mechanisms have not been elucidated, leading to a lack of therapy. The glucagon-like peptide-1 (GLP-1 enhancer, sitagliptin, reduces hyperglycemia but may also trigger direct effects on the heart. METHODS: Goto-Kakizaki (GK rats developed type-II diabetes and received sitagliptin, an anti-hyperglycemic drug (metformin or vehicle (n=10, each. After cardiac structure and function assessment, plasma and left ventricles were isolated for biochemical studies. Cultured cardiomyocytes and fibroblasts were used for in vitro assays. RESULTS: Untreated GK rats exhibited hyperglycemia, hyperlipidemia, plasma GLP-1 decrease, and cardiac cell-death, hypertrophy, fibrosis and prolonged deceleration time. Moreover, cardiac pro-apoptotic/necrotic, hypertrophic and fibrotic factors were up-regulated. Importantly, both sitagliptin and metformin lessened all these parameters. In cultured cardiomyocytes and cardiac fibroblasts, high-concentration of palmitate or glucose induced cell-death, hypertrophy and fibrosis. Interestingly, GLP-1 and its insulinotropic-inactive metabolite, GLP-1(9-36, alleviated these responses. In addition, despite a specific GLP-1 receptor was only detected in cardiomyocytes, GLP-1 isoforms attenuated the pro-fibrotic expression in cardiomyocytes and fibroblasts. In addition, GLP-1 receptor signalling may be linked to PPARδ activation, and metformin may also exhibit anti-apoptotic/necrotic and anti-fibrotic direct effects in cardiac cells. CONCLUSIONS: Sitagliptin, via GLP-1 stabilization, promoted cardioprotection in type-II diabetic hearts primarily by limiting hyperglycemia e hyperlipidemia. However, GLP-1 and GLP-1(9-36 promoted survival and anti-hypertrophic/fibrotic effects on cultured cardiac cells, suggesting cell-autonomous cardioprotective actions.

  10. 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.

  11. Flavonoid-rich extract of Chromolaena odorata modulate circulating GLP-1 in Wistar rats: computational evaluation of TGR5 involvement.

    Science.gov (United States)

    Omotuyi, Olaposi Idowu; Nash, Oyekanmi; Inyang, Olumide Kayode; Ogidigo, Joyce; Enejoh, Ojochenemi; Okpalefe, Okiemute; Hamada, Tsuyoshi

    2018-02-01

    Chromolaena odorata is a major bio-resource in folkloric treatment of diabetes. In the present study, its anti-diabetic component and underlying mechanism were investigated. A library containing 140 phytocompounds previously characterized from C. odorata was generated and docked (Autodock Vina) into homology models of dipeptidyl peptidase (DPP)-4, Takeda-G-protein-receptor-5 (TGR5), glucagon-like peptide 1 (GLP1) receptor, renal sodium dependent glucose transporter (SGLUT)-1/2 and nucleotide-binding oligomerization domain (NOD) proteins 1&2. GLP-1 gene (RT-PCR) modulation and its release (EIA) by C. odorata were confirmed in vivo. From the docking result above, TGR5 was identified as a major target for two key C. odorata flavonoids (5,7-dihydroxy-6-4-dimethoxyflavanone and homoesperetin-7-rutinoside); sodium taurocholate and C. odorata powder included into the diet of the animals both raised the intestinal GLP-1 expression versus control ( p  < 0.05); When treated with flavonoid-rich extract of C. odorata (CoF) or malvidin, circulating GLP-1 increased by 130.7% in malvidin-treated subjects (0 vs. 45 min). CoF treatment also resulted in 128.5 and 275% increase for 10 and 30 mg/kg b.w., respectively. The results of this study support that C. odorata flavonoids may modulate the expression of GLP-1 and its release via TGR5. This finding may underscore its anti-diabetic potency.

  12. GLP-1 secretion is increased by inflammatory stimuli in an IL-6-dependent manner, leading to hyperinsulinemia and blood glucose lowering.

    Science.gov (United States)

    Kahles, Florian; Meyer, Christina; Möllmann, Julia; Diebold, Sebastian; Findeisen, Hannes M; Lebherz, Corinna; Trautwein, Christian; Koch, Alexander; Tacke, Frank; Marx, Nikolaus; Lehrke, Michael

    2014-10-01

    Hypoglycemia and hyperglycemia are both predictors for adverse outcome in critically ill patients. Hyperinsulinemia is induced by inflammatory stimuli as a relevant mechanism for glucose lowering in the critically ill. The incretine hormone GLP-1 was currently found to be induced by endotoxin, leading to insulin secretion and glucose lowering under inflammatory conditions in mice. Here, we describe GLP-1 secretion to be increased by a variety of inflammatory stimuli, including endotoxin, interleukin-1β (IL-1β), and IL-6. Although abrogation of IL-1 signaling proved insufficient to prevent endotoxin-dependent GLP-1 induction, this was abolished in the absence of IL-6 in respective knockout animals. Hence, we found endotoxin-dependent GLP-1 secretion to be mediated by an inflammatory cascade, with IL-6 being necessary and sufficient for GLP-1 induction. Functionally, augmentation of the GLP-1 system by pharmacological inhibition of DPP-4 caused hyperinsulinemia, suppression of glucagon release, and glucose lowering under endotoxic conditions, whereas inhibition of the GLP-1 receptor led to the opposite effect. Furthermore, total GLP-1 plasma levels were profoundly increased in 155 critically ill patients presenting to the intensive care unit (ICU) in comparison with 134 healthy control subjects. In the ICU cohort, GLP-1 plasma levels correlated with markers of inflammation and disease severity. Consequently, GLP-1 provides a novel link between the immune system and the gut with strong relevance for metabolic regulation in context of inflammation. © 2014 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.

  13. Dissecting the salt dependence of the Tus-Ter protein-DNA complexes by high-throughput differential scanning fluorimetry of a GFP-tagged Tus.

    Science.gov (United States)

    Moreau, Morgane J J; Schaeffer, Patrick M

    2013-12-01

    The analysis of the salt dependence of protein-DNA complexes provides useful information about the non-specific electrostatic and sequence-specific parameters driving complex formation and stability. The differential scanning fluorimetry of GFP-tagged protein (DSF-GTP) assay has been geared with an automatic Tm peak recognition system and was applied for the high-throughput (HT) determination of salt-induced effects on the GFP-tagged DNA replication protein Tus in complex with various Ter and Ter-lock sequences. The system was designed to generate two-dimensional heat map profiles of Tus-GFP protein stability allowing for a comparative study of the effect of eight increasing salt concentrations on ten different Ter DNA species at once. The data obtained with the new HT DSF-GTP allowed precise dissection of the non-specific electrostatic and sequence-specific parameters driving Tus-Ter and Tus-Ter-lock complex formation and stability. The major factor increasing the thermal resistance of Tus-Ter-lock complexes in high-salt is the formation of the TT-lock, e.g. a 10-fold higher Kspe was obtained for Tus-GFP:Ter-lockB than for Tus-GFP:TerB. It is anticipated that the system can be easily adapted for the study of other protein-DNA complexes.

  14. GLP-1-RA Corrects Mitochondrial Labile Iron Accumulation and Improves β-Cell Function in Type 2 Wolfram Syndrome.

    Science.gov (United States)

    Danielpur, Liron; Sohn, Yang-Sung; Karmi, Ola; Fogel, Chen; Zinger, Adar; Abu-Libdeh, Abdulsalam; Israeli, Tal; Riahi, Yael; Pappo, Orit; Birk, Ruth; Zangen, David H; Mittler, Ron; Cabantchik, Zvi-Ioav; Cerasi, Erol; Nechushtai, Rachel; Leibowitz, Gil

    2016-10-01

    Type 2 Wolfram syndrome (T2-WFS) is a neuronal and β-cell degenerative disorder caused by mutations in the CISD2 gene. The mechanisms underlying β-cell dysfunction in T2-WFS are not known, and treatments that effectively improve diabetes in this context are lacking. Unraveling the mechanisms of β-cell dysfunction in T2-WFS and the effects of treatment with GLP-1 receptor agonist (GLP-1-RA). A case report and in vitro mechanistic studies. We treated an insulin-dependent T2-WFS patient with the GLP-1-RA exenatide for 9 weeks. An iv glucose/glucagon/arginine stimulation test was performed off-drug before and after intervention. We generated a cellular model of T2-WFS by shRNA knockdown of CISD2 (nutrient-deprivation autophagy factor-1 [NAF-1]) in rat insulinoma cells and studied the mechanisms of β-cell dysfunction and the effects of GLP-1-RA. Treatment with exenatide resulted in a 70% reduction in daily insulin dose with improved glycemic control, as well as an off-drug 7-fold increase in maximal insulin secretion. NAF-1 repression in INS-1 cells decreased insulin content and glucose-stimulated insulin secretion, while maintaining the response to cAMP, and enhanced the accumulation of labile iron and reactive oxygen species in mitochondria. Remarkably, treatment with GLP-1-RA and/or the iron chelator deferiprone reversed these defects. NAF-1 deficiency leads to mitochondrial labile iron accumulation and oxidative stress, which may contribute to β-cell dysfunction in T2-WFS. Treatment with GLP-1-RA and/or iron chelation improves mitochondrial function and restores β-cell function. Treatment with GLP-1-RA, probably aided by iron chelation, should be considered in WFS and other forms of diabetes associated with iron dysregulation.

  15. GLP-1 secretion is stimulated by 1,10-phenanthroline via colocalized T2R5 signal transduction in human enteroendocrine L cell

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jiyoung; Kim, Ki-Suk; Kim, Kang-Hoon; Lee, In-Seung; Jeong, Hyeon-soo; Kim, Yumi; Jang, Hyeung-Jin, E-mail: hjjang@khu.ac.kr

    2015-12-04

    Glucagon-like peptide-1 (GLP-1) hormone is known to regulate blood glucose by an insulinotropic effect and increases proliferation as and also prevents apoptosis of pancreatic β cells. We know that GLP-1 is secreted by nutrients such as fatty acids and sweet compounds but also bitter compounds via stimulation of G-protein coupled receptors (GPCRs) in the gut. Among these, bitter compounds are multiply-contained in phytochemicals or artificial materials and perceived as ligands of various bitter taste receptors. We hypothesized that GLP-1 hormone is secreted through stimulation of a single bitter taste receptor by 1,10-phenanthroline which is known agonist of taste receptor type 2 member 5 (T2R5). To prove this hypothesis, we used the representatively well-known 1,10-phenanthroline as ligand of single receptor and evaluated the existence of T2R5 by double-labeling immunofluorescence and then 1,10-phenanthroline is able to secrete GLP-1 hormone through stimulation of T2R5 in human enteroendocrine cells. Consequently, we verify that GLP-1 hormone is colocalized with T2R5 in the human duodenum and ileum tissue and is secreted by 1,10-phenanthroline via T2R5 signal transduction in differentiated human enteroendocrine L cells. - Highlights: • Taste receptor type 2 member 5 (T2R5) is colocalized with GLP-1 hormone in human enteroendocrine cells. • GLP-1 secretion is stimulated by 1,10-phenanthroline via stimulation of T2R5. • Inhibition of the bitter taste pathway reduce GLP-1 secretion.

  16. GLP-1 secretion is stimulated by 1,10-phenanthroline via colocalized T2R5 signal transduction in human enteroendocrine L cell

    International Nuclear Information System (INIS)

    Park, Jiyoung; Kim, Ki-Suk; Kim, Kang-Hoon; Lee, In-Seung; Jeong, Hyeon-soo; Kim, Yumi; Jang, Hyeung-Jin

    2015-01-01

    Glucagon-like peptide-1 (GLP-1) hormone is known to regulate blood glucose by an insulinotropic effect and increases proliferation as and also prevents apoptosis of pancreatic β cells. We know that GLP-1 is secreted by nutrients such as fatty acids and sweet compounds but also bitter compounds via stimulation of G-protein coupled receptors (GPCRs) in the gut. Among these, bitter compounds are multiply-contained in phytochemicals or artificial materials and perceived as ligands of various bitter taste receptors. We hypothesized that GLP-1 hormone is secreted through stimulation of a single bitter taste receptor by 1,10-phenanthroline which is known agonist of taste receptor type 2 member 5 (T2R5). To prove this hypothesis, we used the representatively well-known 1,10-phenanthroline as ligand of single receptor and evaluated the existence of T2R5 by double-labeling immunofluorescence and then 1,10-phenanthroline is able to secrete GLP-1 hormone through stimulation of T2R5 in human enteroendocrine cells. Consequently, we verify that GLP-1 hormone is colocalized with T2R5 in the human duodenum and ileum tissue and is secreted by 1,10-phenanthroline via T2R5 signal transduction in differentiated human enteroendocrine L cells. - Highlights: • Taste receptor type 2 member 5 (T2R5) is colocalized with GLP-1 hormone in human enteroendocrine cells. • GLP-1 secretion is stimulated by 1,10-phenanthroline via stimulation of T2R5. • Inhibition of the bitter taste pathway reduce GLP-1 secretion.

  17. Therapies for inter-relating diabetes and obesity - GLP-1 and obesity

    DEFF Research Database (Denmark)

    Iepsen, Eva Pers Winning; Torekov, Signe S; Holst, Jens Juul

    2014-01-01

    INTRODUCTION: The dramatic rise in the prevalence of obesity and type 2 diabetes mellitus (T2DM) is associated with increased mortality, morbidity as well as public health care expenses worldwide. The need for effective and long-lasting pharmaceutical treatment is obvious. The record of anti-obesity...... drugs has been poor so far and the only efficient treatment today is bariatric surgery. Research has indicated that appetite inhibiting hormones from the gut may have a therapeutic potential in obesity. The gut incretin hormone, glucagon-like peptide-1 (GLP-1), appears to be involved in both peripheral...... and central pathways mediating satiety. Clinical trials have shown that two GLP-1 receptor agonists exenatide and liraglutide have a weight-lowering potential in non-diabetic obese individuals. Furthermore, they may also hold a potential in preventing diabetes as compared to other weight loss agents. AREAS...

  18. Ghrelin suppresses cholecystokinin (CCK), peptide YY (PYY) and glucagon-like peptide-1 (GLP-1) in the intestine, and attenuates the anorectic effects of CCK, PYY and GLP-1 in goldfish (Carassius auratus).

    Science.gov (United States)

    Blanco, Ayelén Melisa; Bertucci, Juan Ignacio; Valenciano, Ana Isabel; Delgado, María Jesús; Unniappan, Suraj

    2017-07-01

    Ghrelin is an important gut-derived hormone with an appetite stimulatory role, while most of the intestinal hormones, including cholecystokinin (CCK), peptide YY (PYY) and glucagon-like peptide-1 (GLP-1), are appetite-inhibitors. Whether these important peptides with opposing roles on food intake interact to regulate energy balance in fish is currently unknown. The aim of this study was to characterize the putative crosstalk between ghrelin and CCK, PYY and GLP-1 in goldfish (Carassius auratus). We first determined the localization of CCK, PYY and GLP-1 in relation to ghrelin and its main receptor GHS-R1a (growth hormone secretagogue 1a) in the goldfish intestine by immunohistochemistry. Colocalization of ghrelin/GHS-R1a and CCK/PYY/GLP-1 was found primarily in the luminal border of the intestinal mucosa. In an intestinal explant culture, a significant decrease in prepro-cck, prepro-pyy and proglucagon transcript levels was observed after 60min of incubation with ghrelin, which was abolished by preincubation with the GHS-R1a ghrelin receptor antagonist [D-Lys3]-GHRP-6 (except for proglucagon). The protein expression of PYY and GLP-1 was also downregulated by ghrelin. Finally, intraperitoneal co-administration of CCK, PYY or GLP-1 with ghrelin results in no modification of food intake in goldfish. Overall, results of the present study show for the first time in fish that ghrelin exerts repressive effects on enteric anorexigens. It is likely that these interactions mediate the stimulatory effects of ghrelin on feeding and metabolism in fish. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Vascular, but not luminal, activation of FFAR1 (GPR40) stimulates GLP-1 secretion from isolated perfused rat small intestine

    DEFF Research Database (Denmark)

    Christensen, Louise Wulff; Kuhre, Rune Ehrenreich; Janus, Charlotte

    2015-01-01

    -protein-cou- pled receptor, FFAR1 (previously GPR40), expressed on L cells and activated by long-chain fatty acids (LCFAs) is a potential target. A link between FFAR1 activation and GLP-1 secretion has been demonstrated in cellular models and small-molecule FFAR1 agonists have been developed. In this study, we exam......- ined the effect of FFAR1 activation on GLP-1 secretion using isolated, per- fused small intestines from rats, a physiologically relevant model allowing distinction between direct and indirect effects of FFAR1 activation. The endogenous FFAR1 ligand, linoleic acid (LA), and four synthetic FFAR1 ago...

  20. Polymorphism of glucagon-like peptide-1 receptor gene (rs1042044 ...

    African Journals Online (AJOL)

    patience

    2015-02-16

    Feb 16, 2015 ... turnover via GLP-1 receptors (GLP1Rs) in postmenopausal state. Furthermore, polymorphisms in. GLP1R gene were suggested to affect the function of GLP1Rs and be associated with many diseases. However, the relationships between GLP1R polymorphisms and osteoporosis susceptibility and bone.

  1. Polymorphism of glucagon-like peptide-1 receptor gene (rs1042044 ...

    African Journals Online (AJOL)

    Previous investigations indicated that glucagon-like peptide-1 (GLP-1) played important roles in bone turnover via GLP-1 receptors (GLP1Rs) in postmenopausal state. Furthermore, polymorphisms in GLP1R gene were suggested to affect the function of GLP1Rs and be associated with many diseases. However, the ...

  2. CREB mediates the insulinotropic and anti-apoptotic effects of GLP-1 signaling in adult mouse β-cells

    Directory of Open Access Journals (Sweden)

    Soona Shin

    2014-11-01

    Conclusions: In sum, our studies using conditional gene deletion put into question current notions about the importance of CREB in regulating β-cell function and mass. However, we reveal an important role for CREB in the β-cell response to GLP-1 receptor signaling, further validating CREB as a therapeutic target for diabetes.

  3. {sup 18}F-radiolabeled analogs of exendin-4 for PET imaging of GLP-1 in insulinoma

    Energy Technology Data Exchange (ETDEWEB)

    Kiesewetter, Dale O.; Ma, Ying; Niu, Gang; Quan, Qimeng; Guo, Ning; Chen, Xiaoyuan [National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Laboratory of Molecular Imaging and Nanomedicine (LOMIN), Bethesda, MD (United States); Gao, Haokao [National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Laboratory of Molecular Imaging and Nanomedicine (LOMIN), Bethesda, MD (United States); Fourth Military Medical University, Department of Cardiology, Xijing Hospital, Xi' an (China)

    2012-03-15

    Glucagon-like peptide type 1 (GLP-1) is an incretin peptide that augments glucose-stimulated insulin release following oral consumption of nutrients. Its message is transmitted via a G protein-coupled receptor called GLP-1R, which is colocalized with pancreatic {beta}-cells. The GLP-1 system is responsible for enhancing insulin release, inhibiting glucagon production, inhibiting hepatic gluconeogenesis, inhibiting gastric mobility, and suppression of appetite. The abundance of GLP-1R in pancreatic {beta}-cells in insulinoma, a cancer of the pancreas, and the activity of GLP-1 in the cardiovascular system have made GLP-1R a target for molecular imaging. We prepared {sup 18}F radioligands for GLP-1R by the reaction of [{sup 18}F]FBEM, a maleimide prosthetic group, with [Cys{sup 0}] and [Cys{sup 40}] analogs of exendin-4. The binding affinity, cellular uptake and internalization, in vitro stability, and uptake and specificity of uptake of the resulting compounds were determined in an INS-1 xenograft model in nude mice. The [{sup 18}F]FBEM-[Cys{sup x}]-exendin-4 analogs were obtained in good yield (34.3 {+-} 3.4%, n = 11), based on the starting compound [{sup 18}F]FBEM, and had a specific activity of 45.51 {+-} 16.28 GBq/{mu}mol (1.23 {+-} 0.44 Ci/{mu}mol, n = 7) at the end of synthesis. The C-terminal isomer, [{sup 18}F]FBEM-[Cys{sup 40}]-exendin-4, had higher affinity for INS-1 tumor cells (IC{sub 50} 1.11 {+-} 0.057 nM) and higher tumor uptake (25.25 {+-} 3.39 %ID/g at 1 h) than the N-terminal isomer, [{sup 18}F]FBEM-[Cys{sup 0}]-exendin-4 (IC{sub 50} 2.99 {+-} 0.06 nM, uptake 7.20 {+-} 1.26 %ID/g at 1 h). Uptake of both isomers into INS-1 tumor, pancreas, stomach, and lung could be blocked by preinjection of nonradiolabeled [Cys{sup x}]-exendin-4 (p < 0.05). [{sup 18}F]FBEM-[Cys{sup 40}]-exendin-4 and [{sup 18}F]FBEM-[Cys{sup 0}]-exendin-4 have high affinity for GLP-1R and display similar in vitro cell internalization. The higher uptake into INS-1 xenograft tumors

  4. Glucose Tolerance, Lipids, and GLP-1 Secretion in JCR:LA-cp Rats Fed a High Protein Fiber Diet

    Science.gov (United States)

    Reimer, Raylene A.; Russell, James C.

    2013-01-01

    Background We have shown that individually, dietary fiber and protein increase secretion of the anorexigenic and insulinotropic hormone, glucagon-like peptide-1 (GLP-1). Objective Our objective was to combine, in one diet, high levels of fiber and protein to maximize GLP-1 secretion, improve glucose tolerance, and reduce weight gain. Methods and Procedures Lean (+/?) and obese (cp/cp) male James C Russell corpulent (JCR:LA-cp) rats lacking a functional leptin receptor were fed one of four experimental diets (control, high protein (HP), high fiber (HF, prebiotic fiber inulin), or combination (CB)) for 3 weeks. An oral glucose tolerance test (OGTT) was performed to evaluate plasma GLP-1, insulin and glucose. Plasma lipids and intestinal proglucagon mRNA expression were determined. Results Energy intake was lower with the HF diet in lean and obese rats. Weight gain did not differ between diets. Higher colonic proglucagon mRNA in lean rats fed a CB diet was associated with higher GLP-1 secretion during OGTT. The HP diet significantly reduced plasma glucose area under the curve (AUC) during OGTT in obese rats, which reflected both an increased GLP-1 AUC and higher fasting insulin. Diets containing inulin resulted in the lowest plasma triglyceride and total cholesterol levels. Discussion Overall, combining HP with HF in the diet increased GLP-1 secretion in response to oral glucose, but did not improve glucose tolerance or lipid profiles more than the HF diet alone did. We also suggest that glycemic and insulinemic response to prebiotics differ among rat models and future research work should examine their role in improving glucose tolerance in diet-induced vs. genetic obesity with overt hyperleptinemia. PMID:18223610

  5. Effects of exendin-4 and selenium on the expression of GLP-1R, IRS-1, and preproinsulin in the pancreas of diabetic rats.

    Science.gov (United States)

    Barakat, Ghinwa; Moustafa, Mohamed E; Khalifeh, Ibrahim; Hodroj, Mohammad H; Bikhazi, Anwar; Rizk, Sandra

    2016-08-01

    The mechanisms by which exendin-4 and selenium exert their antidiabetic actions are still unclear. Here, we investigated the effects of exendin-4 or selenium administration on the expression of glucagon-like peptide-1 receptor (GLP-1R), insulin receptor substrate-1 (IRS-1), and preproinsulin in the pancreas of diabetic rats. Diabetes was induced by streptozotocin administration. Diabetic rats were injected intraperitoneally with 0.03 μg exendin-4/kg body weight/daily or treated with 5 ppm selenium in drinking water for a period of 4 weeks. GLP-1R and IRS-1 levels were decreased while the level of preproinsulin messenger RNA (mRNA) was increased in the pancreas of diabetic untreated rats, as compared to that in control rats. Treatment of diabetic rats with exendin-4 increased protein and mRNA levels of GLP-1R, and IRS-1, and the mRNA level of preproinsulin in the pancreas, as compared to their levels in diabetic untreated rats. Selenium treatment of diabetic rats increased the pancreatic mRNA levels of GLP-1R, IRS-1, and preproinsulin. Exendin-4 or selenium treatment of diabetic rats also increased the numbers of pancreatic islets and GLP-1R molecules in the pancreas. Therefore, exendin-4 and selenium may exert their antidiabetic effects by increasing GLP-1R, IRS-1, and preproinsulin expression in the pancreas and by increasing the number of pancreatic islets.

  6. The bile acid-sequestering resin sevelamer eliminates the acute GLP-1 stimulatory effect of endogenously released bile acids in patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Brønden, Andreas; Albér, Anders; Rohde, Ulrich

    2018-01-01

    AIMS: The discovery of the specific bile acid receptors farnesoid X receptor (FXR) and Takeda G protein-coupled receptor 5 (TGR5) in enteroendocrine L cells has prompted research focusing on the impact of bile acids on glucagon-like peptide-1 (GLP-1) secretion and glucose metabolism. The aim of t...

  7. Different domains of the glucagon and glucagon-like peptide-1 receptors provide the critical determinants of ligand selectivity

    DEFF Research Database (Denmark)

    Runge, S; Wulff, B S; Madsen, K

    2003-01-01

    analysed chimeric glucagon/GLP-1 peptides for their ability to bind and activate the glucagon receptor, the GLP-1 receptor and chimeric glucagon/GLP-1 receptors. The chimeric peptide GLP-1(7-20)/glucagon(15-29) was unable to bind and activate the glucagon receptor. Substituting the glucagon receptor core......-terminus of chimera A with the corresponding glucagon receptor segments re-established the ability to distinguish GLP-1(7-20)/glucagon(15-29) from glucagon. Corroborant results were obtained with the opposite chimeric peptide glucagon(1-14)/GLP-1(21-37). (3) The results suggest that the glucagon and GLP-1 receptor......(1) Glucagon and glucagon-like peptide-1 (GLP-1) are homologous peptide hormones with important functions in glucose metabolism. The receptors for glucagon and GLP-1 are homologous family B G-protein coupled receptors. The GLP-1 receptor amino-terminal extracellular domain is a major determinant...

  8. Effects of the glucagon-like polypeptide-1 analogue (Val8)GLP-1 on learning, progenitor cell proliferation and neurogenesis in the C57B/16 mouse brain.

    Science.gov (United States)

    McGovern, Stephen F J; Hunter, Kerry; Hölscher, Christian

    2012-09-14

    Type 2 diabetes (T2DM) has been identified as a risk factor for Alzheimer's disease. Here, we tested the properties of the glucagon-like polypetide-1 (GLP-1) analogue (Val8)GLP-1, a drug originally developed as a treatment for T2DM at a range of doses (2.5 nmol; 25 nmol; 100 nmol; or 250 nmol/kg bw ip.) in an acute memory study in wild type C57B/l6 mice. We also tested (Val8)GLP-1 and the GLP-1 receptor antagonist exendin (9-39) in a chronic study (3 weeks at 25 nmol/kg bw ip. once-daily). We found that (Val8)GLP-1 crossed the blood brain barrier readily and that peripheral injection increased levels in the brain 30 min post-injection ip. but not 2h post-injection in rats. In the acute study, the low dose of 2.5 nmol/kg ip. enhanced motor activity in the open field task, while total distance travelled, exploratory behaviour and anxiety was not affected at any dose. Learning an object recognition task was not affected either. In the chronic study, no effect was observed in the open field assessment. The antagonist exendin (9-39) impaired object recognition learning and spatial learning in a water maze task, demonstrating the importance of GLP-1 signalling in memory formation. Locomotor activity was also affected in some cases. Blood sugar levels and insulin sensitivity was not affected in chronically treated mice. Neuronal stem cells and neurogenesis was enhanced by (Val8)GLP-1 in the dentate gyrus of wild type mice. The results demonstrate that (Val8)GLP-1 is safe in a range of doses, crosses the BBB and has potentially beneficial effects in the CNS by enhancing neurogenesis. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Selecting GLP-1 agonists in the management of type 2 diabetes: differential pharmacology and therapeutic benefits of liraglutide and exenatide

    Directory of Open Access Journals (Sweden)

    Jonathan Pinkney

    2010-08-01

    Full Text Available Jonathan Pinkney1, Thomas Fox1, Lakshminarayan Ranganath21Department of Diabetes and Endocrinology, Peninsula College of Medicine and Dentistry, Plymouth, United Kingdom; 2Department of Clinical Biochemistry and Metabolic Medicine, Royal Liverpool University Hospital, Liverpool, United KingdomAbstract: Failure of secretion of the incretin hormone glucagon-like peptide-1 (GLP-1 plays a prominent role in type 2 diabetes, and restoration of GLP-1 action is an important therapeutic objective. Although the short duration of action of GLP-1 renders it unsuited to therapeutic use, 2 long-acting GLP-1 receptor agonists, exenatide and liraglutide, represent a significant advance in treatment. In controlled trials, both produce short-term glucose-lowering effects, with the reduction in hemoglobin A1c of up to 1.3%. These responses are often superior to those observed with additional oral agents. However, unlike sulfonylureas, thiazolidinediones, or insulin, all of which lead to significant weight gain, GLP-1 receptor agonists uniquely result in long-term weight loss of around 5 kg, and higher doses may enhance this further. Reduction in blood pressure of 2–7 mm Hg also has been observed. Both drugs produce transient mild gastrointestinal side effects; although mild hypoglycemia can occur, this is usually in combination with other hypoglycemic therapies. However, serious hypoglycemia and acute pancreatitis are rare. The once-daily dosage of liraglutide makes it more convenient than twice-daily dosage of prandial exenatide, and a superior glucose-lowering effect was observed in the only head-to-head comparison reported so far. Besides cost, these considerations currently favor liraglutide over exenatide. Further studies are needed to confirm long-term safety, and most importantly, that short-term benefits translate into long-term reductions of diabetes-related cardiovascular events and other complications.Keywords: diabetes, weight loss, glycemic control

  10. Neonatal GLP1R activation limits adult adiposity by durably altering hypothalamic architecture

    Directory of Open Access Journals (Sweden)

    Andrea V. Rozo

    2017-07-01

    Conclusion: These observations suggest that the acute activation of GLP1R in neonates durably alters hypothalamic architecture to limit adult weight gain and adiposity, identifying GLP1R as a therapeutic target for obesity prevention.

  11. Amylin and GLP-1 target different populations of area postrema neurons that are both modulated by nutrient stimuli.

    Science.gov (United States)

    Züger, Daniela; Forster, Karoline; Lutz, Thomas A; Riediger, Thomas

    2013-03-15

    The area postrema mediates the hypophagic effect of the pancreatic hormone amylin and is also sensitive to glucagon-like peptide 1 (GLP-1). Protein seems to modulate amylin responsiveness because amylin seems to produce a stronger hypophagic effect and a stronger c-Fos expression when protein is absent from the diet. Accordingly, amylin induces a stronger c-Fos expression in the AP when injected in fasted compared to ad libitum fed rats. Here we tested the hypothesis that diet-derived protein attenuates the amylin dependent suppression of feeding and AP activation using isocaloric diets that differed in their protein content. Moreover, we investigated whether peripheral amino acid injection attenuates amylin-induced c-Fos expression in fasted rats. Since recent evidence suggests that GLP-1 may also reduce eating via the AP we tested whether 24 h fasting also increases neuronal AP responsiveness to GLP-1 similar to the fasting-induced increase in amylin responsiveness. Finally, we used the calcitonin receptor (CTR) as an immunohistochemical marker for amylin-receptive AP neurons to investigate whether amylin's target neurons differ from GLP-1 responsive AP neurons. We also dissociated amylin responsive cells from neurons implicated in other AP-mediated functions such as aversion or blood pressure regulation. For this purpose, we conducted c-Fos/CTR double staining after LiCl or angiotensin II treatment, respectively. Amylin (5 μg/kg s.c.) was more effective to reduce the intake of a 1% vs. an 8% or 18% protein diet and to induce c-Fos expression in the AP in rats receiving 1% vs. 18% protein diet. Increased protein intake was associated with increased blood amino acid levels. Peripheral injection of amino acids (1 g/kg i.p.) attenuated the amylin-induced AP activation in 24 h fasted rats. Similar to amylin, GLP-1 (100 μg/kg i.p.) elicited a significant c-Fos response only in fasted but not in ad libitum fed rats. However, in contrast to a high co-localization of

  12. Immunoassays for the incretin hormones GIP and GLP-1

    DEFF Research Database (Denmark)

    Deacon, Carolyn F; Holst, Jens J

    2009-01-01

    The measurement of the incretin hormones, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), using immunologically based assays is made difficult by the fact that the processing of the precursor molecules gives rise to a number of different peptides which cross......-react with antisera raised against the two hormones. For GLP-1, the picture is further complicated because of the necessity to differentiate between the intestinal and pancreatic proglucagon products. Finally, once secreted, both incretins are rapidly degraded by the enzyme dipeptidyl peptidase-4 (DPP-4) to generate....... The use of highly specific assays using well-characterised antisera and careful sample handling is therefore required for a reliable determination of incretin hormone concentrations....

  13. Inhibitory effect of GLP-1 on gastric motility persists after vagal deafferentation in pigs

    DEFF Research Database (Denmark)

    Nagell, Carl Frederik; Wettergren, André; Ørskov, Cathrine

    2006-01-01

    BACKGROUND: Glucagon-like peptide 1 (GLP-1) is an intestinal hormone that is secreted in response to meal ingestion. GLP-1 inhibits gastric emptying and reduces postprandial gastric secretion and may play a physiological regulatory role in controlling appetite and energy intake in humans. The GLP-1...

  14. Metabolic effects of short-term GLP-1 treatment in insulin resistant heart failure patients

    DEFF Research Database (Denmark)

    Nielsen, Bent Roni Ranghøj; Wiggers, H; Halbirk, M

    2012-01-01

    calorimetry, forearm, and tracer methods.7 insulin resistant HF (EF 28%±2) patients completed the protocol. GLP-1 decreased plasma glucose levels (p=0.048) and improved glucose tolerance. 4 patients had hypoglycemic events during GLP-1 vs. none during placebo. GLP-1 treatment tended to increase whole body...

  15. Cost-effectiveness of once daily GLP-1 receptor agonist lixisenatide compared to bolus insulin both in combination with basal insulin for the treatment of patients with type 2 diabetes in Norway.

    Science.gov (United States)

    Huetson, Pernilla; Palmer, James L; Levorsen, Andrée; Fournier, Marie; Germe, Maeva; McLeod, Euan

    2015-01-01

    Lixisenatide is a potent, selective and short-acting once daily prandial glucagon-like peptide-1 receptor agonist which lowers glycohemoglobin and body weight by clinically significant amounts in patients with type 2 diabetes treated with basal insulin, with limited risk of hypoglycemia. To assess the cost-effectiveness of lixisenatide versus bolus insulin, both in combination with basal insulin, in patients with type 2 diabetes in Norway. The IMS CORE Diabetes Model, a non-product-specific and validated simulation model, was used to make clinical and cost projections. Transition probabilities, risk adjustments and the progression of complication risk factors were derived from the UK Prospective Diabetes Study, supplemented with Norwegian data. Patients were assumed to receive combination treatment with basal insulin, lixisenatide or bolus insulin therapy for 3 years, followed by intensification of a basal-bolus insulin regimen for their remaining lifetime. Simulated healthcare costs, taken from the public payer perspective, were derived from microcosting and diagnosis related groups, discounted at 4% per annum and reported in Norwegian krone (NOK). Productivity costs were also captured based on extractions from the Norwegian Labor and Welfare Administration. Health state utilities were derived from a systematic literature review. Sensitivity and scenario analyses were performed. Lixisenatide in combination with basal insulin was associated with increased quality-adjusted life years (QALYs) and reduced lifetime healthcare costs compared to bolus insulin in combination with basal insulin in patients with Type 2 diabetes, and can be considered dominant. The net monetary benefit of lixisenatide versus bolus insulin was NOK 39,369 per patient. Results were sensitive to discounting, the application of excess body weight associated disutility and uncertainty surrounding the changes in HbA1c. Lixisenatide may be considered an economically efficient therapy in combination

  16. GLP-1 Treatment Improves Diabetic Retinopathy by Alleviating Autophagy through GLP-1R-ERK1/2-HDAC6 Signaling Pathway.

    Science.gov (United States)

    Cai, Xiangsheng; Li, Jingjing; Wang, Mingzhu; She, Miaoqin; Tang, Yongming; Li, Jinlong; Li, Hongwei; Hui, Hongxiang

    2017-01-01

    Objective: Apoptosis and autophagy of retinal cells, which may be induced by oxidative stress, are tightly associated with the pathogenesis of diabetic retinopathy (DR). The autophagy induced by oxidative stress is considered as excessively stimulated autophagy, which accelerates the progression of DR. This study aims to investigate the protective effect of GLP-1 treatment on alleviating apoptosis and autophagy of retinal cells in type 2 diabetic rats and reveals its possible mechanism. Methods: Type 2 diabetic rats were induced by fed with high sugar, high fat diet and followed with streptozotocin injection. GLP-1 was applied to treat the diabetic rats for one week after the onset of diabetes. The expressions of oxidative stress-related enzymes, retinal GLP-1R, mitochondria-dependent apoptosis- related genes, autophagy markers, and autophagy-associated pathway genes were studied by Western blotting or immunohistochemistry analysis. Results: GLP-1treatment reduced the levels of NOX3 and SOD2 in DR. The expression of BCL2 was increased, while the levels of caspase3 and LC3B were reduced through GLP-1 treatment in DR . GLP-1 treatment restored the GLP-1R expression and decreased the levels of phosphorylated AKT and phosphorylated ERK1/2, which was accompanied with the reduction of the HDAC6 levels in DR. Conclusions: GLP-1 treatment can alleviate autophagy which may be induced by oxidative stress; this protective effect is likely through GLP-1R-ERK1/2-HDAC6 signaling pathway.

  17. At the centennial of Michaelis and Menten, competing Michaelis-Menten steps explain effect of GLP-1 on blood-brain transfer and metabolism of glucose.

    Science.gov (United States)

    Gejl, Michael; Rungby, Jørgen; Brock, Birgitte; Gjedde, Albert

    2014-08-01

    Glucagon-like peptide-1 (GLP-1) is a potent insulinotropic incretin hormone with both pancreatic and extrapancreatic effects. Studies of GLP-1 reveal significant effects in regions of brain tissue that regulate appetite and satiety. GLP-1 mimetics are used for the treatment of type 2 diabetes mellitus. GLP-1 interacts with peripheral functions in which the autonomic nervous system plays an important role, and emerging pre-clinical findings indicate a potential neuroprotective role of the peptide, for example in models of stroke and in neurodegenerative disorders. A century ago, Leonor Michaelis and Maud Menten described the steady-state enzyme kinetics that still apply to the multiple receptors, transporters and enzymes that define the biochemical reactions of the brain, including the glucose-dependent impact of GLP-1 on blood-brain glucose transfer and metabolism. This MiniReview examines the potential of GLP-1 as a molecule of interest for the understanding of brain energy metabolism and with reference to the impact on brain metabolism related to appetite and satiety regulation, stroke and neurodegenerative disorders. These effects can be understood only by reference to the original formulation of the Michaelis-Menten equation as applied to a chain of kinetically controlled steps. Indeed, the effects of GLP-1 receptor activation on blood-brain glucose transfer and brain metabolism of glucose depend on the glucose concentration and relative affinities of the steps both in vitro and in vivo, as in the pancreas. © 2014 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

  18. Evidence for paracrine/autocrine regulation of GLP-1-producing cells

    DEFF Research Database (Denmark)

    Kappe, Camilla; Zhang, Qimin; Holst, Jens Juul

    2013-01-01

    Glucagon-like peptide-1 (GLP-1), secreted from gut L cells upon nutrient intake, forms the basis for novel drugs against type 2 diabetes (T2D). Secretion of GLP-1 has been suggested to be impaired in T2D and in conditions associated with hyperlipidemia and insulin resistance. Further, recent...... studies support lipotoxicity of GLP-1-producing cells in vitro. However, little is known about the regulation of L-cell viability/function, the effects of insulin signaling, or the potential effects of stable GLP-1 analogs and dipeptidyl peptidase-4 (DPP-4) inhibitors. We determined effects of insulin...... as well as possible autocrine action of GLP-1 on viability/apoptosis of GLP-1-secreting cells in the presence/absence of palmitate, while also assessing direct effects on function. The studies were performed using the GLP-1-secreting cell line GLUTag, and palmitate was used to simulate hyperlipidemia. Our...

  19. Glucagon-like peptide 1 receptor agonist (GLP-1 RA)

    DEFF Research Database (Denmark)

    von Scholten, Bernt Johan; Hansen, Tine Willum; Goetze, Jens Peter

    2015-01-01

    was to investigate the long-term effect on kidney function. METHODS: We included 30 patients in a one-year extension study, all initially treated with liraglutide for seven weeks. During follow-up 23 were treated with liraglutide and seven untreated. Primary outcome was change in GFR ((51)Cr-EDTA plasma clearance......). RESULTS: Patients were 61.5 (10.0) years and HbA(1c) 60.1 (13.8) mmol/mol. Baseline GFR was 100.6 (24.9) mL/min/1.73 m(2) and was reduced by 11 (95% CI: 6.6-15.7, p 24-h systolic blood pressure (SBP), weight, UAER or HbA(1c) (p≥0.33). Geometric mean (IQR......) of UAER was 25.5 (9.9-50.9) mg/d and was reduced by 27 (95% CI: 5-44; p = 0.020)%, and 24-h SBP was reduced by 8.2 (p = 0.048) mmHg. No changes occurred in untreated patients. CONCLUSIONS: Long-term treatment with liraglutide was associated with a reduction in measured GFR similar to the effect during...

  20. The cardioprotective and inotropic components of the postconditioning effects of GLP-1 and GLP-1(9-36)a in an isolated rat heart

    DEFF Research Database (Denmark)

    Ossum, Alvilde; van Deurs, Ulla; Engstrøm, Thomas

    2009-01-01

    GLP-1 and its metabolite GLP-1(9-36)a have been shown to exert cardiotropic effects, and were demonstrated to be cardioprotective agents in isolated, postischemic rat or mouse hearts. An agent's total effect on myocardial performance in a postconditioning paradigm is a sum of its myocyte-preservi......GLP-1 and its metabolite GLP-1(9-36)a have been shown to exert cardiotropic effects, and were demonstrated to be cardioprotective agents in isolated, postischemic rat or mouse hearts. An agent's total effect on myocardial performance in a postconditioning paradigm is a sum of its myocyte...... protocol, as exemplified by use of GLP-1 and GLP-1(9-36)a following a global ischemia in isolated rat hearts. Peptides were administered during the first 15min of 120min reperfusion. GLP-1 0.3nM reduced infarct size from 23.2+/-2.4% to 14.1+/-2.3% of area-at-risk (n=15, P=0.0223), an effect abolished......, rather than any true inotropic effect. In contrast, GLP-1(9-36)a did not reduce infarct size significantly, but acted as a strong negative inotrope in postischemic hearts, causing a contractility deficit (LVDP 58.8%, P=0.0004; RPP 58.2%, P=0.0007; dP/dt(max)=58.2%, P=0.0012), quantifiable by an analysis...

  1. GLP-1 (glucagon-like peptide 1) and truncated GLP-1, fragments of human proglucagon, inhibit gastric acid secretion in humans

    DEFF Research Database (Denmark)

    Schjoldager, B T; Mortensen, P E; Christiansen, J

    1989-01-01

    Glucagon-like peptide 1 amide (GLP-1 amide), a predicted product of the glucagon gene (proglucagon 72-107-amide), and truncated GLP-1 (proglucagon 78-107-amide), recently isolated from porcine small intestine, were infused in doses of 100 and 400 ng/kg/hr and 12.5 and 50 ng/kg/hr, respectively...

  2. A novel GLP-1/GIP dual agonist is more effective than liraglutide in reducing inflammation and enhancing GDNF release in the MPTP mouse model of Parkinson's disease.

    Science.gov (United States)

    Yuan, Ziyue; Li, Dongfang; Feng, Peng; Xue, Guofang; Ji, Chenhui; Li, Guanglai; Hölscher, Christian

    2017-10-05

    Type 2 diabetes mellitus (T2DM) is one of the risk factors for Parkinson's disease (PD). Insulin desensitisation has been observed in the brains of patients, which may promote neurodegeneration. Incretins are a family of growth factors that can re-sensitise insulin signalling. We have previously shown that mimetics of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) have neuroprotective effects in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropypridine (MPTP) mouse model of PD. Recently, dual GLP-1/GIP receptor agonists have been developed. We therefore tested the novel dual agonist DA3-CH in comparison with the best GLP-1 analogue currently on the market, liraglutide (both drugs 25nmol/kg ip once-daily for 7 days) in the MPTP mouse model of PD (25mg/kg ip once-daily for 7 days). In the Rotarod and grip strength assessment, DA3-CH was superior to liraglutide in reversing the MPTP-induced motor impairment. Dopamine synthesis as indicated by levels of tyrosine hydroxylase was much reduced by MPTP in the substantia nigra and striatum, and DA3-CH reversed this while liragutide only partially reversed this. The chronic inflammation response as shown in increased levels of activated microglia and astrocytes was reduced by both drugs. Importantly, expression levels of the neuroprotective growth factor Glial Derived Neurotrophic Factor (GDNF) was much enhanced by both DA3-CH and liragutide. The results demonstrate that the combination of GLP-1 and GIP receptor activation is superior to single GLP-1 receptor activation alone. Therefore, new dual agonists may be a promising treatment for PD. The GLP-1 receptor agonist exendin-4 has already shown disease modifying effects in clinical trials in PD patients. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Glucagon-like peptide-1 (GLP-1) and the regulation of human invariant natural killer T cells: lessons from obesity, diabetes and psoriasis.

    LENUS (Irish Health Repository)

    Hogan, A E

    2011-11-01

    The innate immune cells, invariant natural killer T cells (iNKT cells), are implicated in the pathogenesis of psoriasis, an inflammatory condition associated with obesity and other metabolic diseases, such as diabetes and dyslipidaemia. We observed an improvement in psoriasis severity in a patient within days of starting treatment with an incretin-mimetic, glucagon-like peptide-1 (GLP-1) receptor agonist. This was independent of change in glycaemic control. We proposed that this unexpected clinical outcome resulted from a direct effect of GLP-1 on iNKT cells.

  4. Elevated Postoperative Endogenous GLP-1 Levels Mediate Effects of Roux-en-Y Gastric Bypass on Neural Responsivity to Food Cues

    DEFF Research Database (Denmark)

    Ten Kulve, Jennifer S; Veltman, Dick J; Gerdes, Victor E A

    2017-01-01

    of the GLP-1 receptor antagonist exendin 9-39 (Ex9-39) and placebo were assessed in 10 women before and after RYGB. We used functional MRI to investigate CNS activation in response to visual food cues (pictures) and gustatory food cues (consumption of chocolate milk), comparing results with Ex9-39 versus...... in response to visual and gustatory food cues may be mediated by central effects of GLP-1. Our findings provide further insights into the mechanisms underlying the weight-lowering effects of RYGB.......OBJECTIVE: It has been suggested that weight reduction and improvements in satiety after Roux-en-Y gastric bypass (RYGB) are partly mediated via postoperative neuroendocrine changes. Glucagon-like peptide-1 (GLP-1) is a gut hormone secreted after food ingestion and is associated with appetite...

  5. 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

  6. Neurotensin Is Co-Expressed, Co-Released And Acts Together With Glp-1 And Pyy In Enteroendocrine Control Of Metabolism

    DEFF Research Database (Denmark)

    Grunddal, Kaare Villum; Ratner, Cecilia F; Svendsen, Berit

    2016-01-01

    increasingly multi-hormonal, i.e. co-expressing PYY and neurotensin as they move up the villus. Pro-glucagon promoter and pertussis toxin receptor driven cell ablation and reappearance studies indicated that although all the cells die, the GLP-1 cells reappear more quickly than PYY and neurotensin positive...

  7. In Alzheimer's disease, 6-month treatment with GLP-1 analog prevents decline of brain glucose metabolism

    DEFF Research Database (Denmark)

    Gejl, Michael; Gjedde, Albert; Egefjord, Lærke

    2016-01-01

    In animal models, the incretin hormone GLP-1 affects Alzheimer's disease (AD). We hypothesized that treatment with GLP-1 or an analog of GLP-1 would prevent accumulation of Aβ and raise, or prevent decline of, glucose metabolism (CMRglc) in AD. In this 26-week trial, we randomized 38 patients...... with AD to treatment with the GLP-1 analog liraglutide (n = 18), or placebo (n = 20). We measured Aβ load in brain with tracer [11C]PIB (PIB), CMRglc with [18F]FDG (FDG), and cognition with the WMS-IV scale (ClinicalTrials.gov NCT01469351). The PIB binding increased significantly in temporal lobe...

  8. The insulinotropic effect of exogenous GLP-1 is not affected by acute vagotomy in anaesthetized pigs

    DEFF Research Database (Denmark)

    Veedfald, Simon; Hansen, Marie; Christensen, Louise Wulff

    2016-01-01

    importance? We found no effect of truncal vagotomy on the insulinotropic effect of exogenous GLP-1 and speculate that high circulating levels of GLP-1 after intravenous infusion may have overshadowed any neural signalling component. We propose that further investigations in to the possible vagal afferent...... the vagal trunks were severed in 4/6 groups (vagal trunks were left intact in 2/6 groups), whereupon all infusions were repeated. We found no effect of vagotomy on insulin or glucagon secretion during administration of exogenous GLP-1 in any experiment. We speculate that the effect of exogenous GLP-1...

  9. GLP-1 increases microvascular recruitment but not glucose uptake in human and rat skeletal muscle

    DEFF Research Database (Denmark)

    Sjøberg, Kim Anker; Holst, Jens Juul; Rattigan, Stephen

    2014-01-01

    The insulinotropic gut hormone, glucagon-like-peptide-1 (GLP-1) has been proposed to have effects on vascular function and glucose disposal. However, whether GLP-1 is able to increase microvascular recruitment (MVR) in humans has not been investigated. GLP-1 was infused in the femoral artery...... in overnight fasted healthy young men. Microvascular recruitment was measured with real time contrast-enhanced ultrasound and leg glucose uptake by the leg balance technique with and without inhibition of the insulinotropic response of GLP-1 by co-infusion of octreotide. As a positive control, MVR and leg...

  10. GLP-1 analogs reduce hepatocyte steatosis and improve survival by enhancing the unfolded protein response and promoting macroautophagy.

    Directory of Open Access Journals (Sweden)

    Shvetank Sharma

    Full Text Available Nonalcoholic fatty liver disease (NAFLD is a known outcome of hepatosteatosis. Free fatty acids (FFA induce the unfolded protein response (UPR or endoplasmic reticulum (ER stress that may induce apoptosis. Recent data indicate ER stress to be a major player in the progression of fatty liver to more aggressive lesions. Autophagy on the other hand has been demonstrated to be protective against ER stress-induced cell death. We hypothesized that exendin-4 (GLP-1 analog treatment of fat loaded hepatocytes can reduce steatosis by autophagy which leads to reduced ER stress-related hepatocyte apoptosis.Primary human hepatocytes were loaded with saturated, cis- and trans-unsaturated fatty acids (palmitic, oleic and elaidic acid respectively. Steatosis, induced with all three fatty acids, was significantly resolved after exendin-4 treatment. Exendin-4 sustained levels of GRP78 expression in fat-loaded cells when compared to untreated fat-loaded cells alone. In contrast, CHOP (C/EBP homologous protein; the penultimate protein that leads to ER stress-related cell death was significantly decreased by exendin-4 in hepatocytes loaded with fatty acids. Finally, exendin-4 in fat loaded hepatocytes clearly promoted gene products associated with macroautophagy as measured by enhanced production of both Beclin-1 and LC3B-II, markers for autophagy; and visualized by transmission electron microscopy (TEM. Similar observations were made in mouse liver lysates after mice were fed with high fat high fructose diet and treated with a long acting GLP-1 receptor agonist, liraglutide.GLP-1 proteins appear to protect hepatocytes from fatty acid-related death by prohibition of a dysfunctional ER stress response; and reduce fatty acid accumulation, by activation of both macro-and chaperone-mediated autophagy. These findings provide a novel role for GLP-1 proteins in halting the progression of more aggressive lesions from underlying steatosis in humans afflicted with NAFLD.

  11. Genomic approach to therapeutic target validation identifies a glucose-lowering GLP1R variant protective for coronary heart disease

    Science.gov (United States)

    Scott, Robert A.; Freitag, Daniel F.; Li, Li; Chu, Audrey Y.; Surendran, Praveen; Young, Robin; Grarup, Niels; Stancáková, Alena; Chen, Yuning; V.Varga, Tibor; Yaghootkar, Hanieh; Luan, Jian'an; Zhao, Jing Hua; Willems, Sara M.; Wessel, Jennifer; Wang, Shuai; Maruthur, Nisa; Michailidou, Kyriaki; Pirie, Ailith; van der Lee, Sven J.; Gillson, Christopher; Olama, Ali Amin Al; Amouyel, Philippe; Arriola, Larraitz; Arveiler, Dominique; Aviles-Olmos, Iciar; Balkau, Beverley; Barricarte, Aurelio; Barroso, Inês; Garcia, Sara Benlloch; Bis, Joshua C.; Blankenberg, Stefan; Boehnke, Michael; Boeing, Heiner; Boerwinkle, Eric; Borecki, Ingrid B.; Bork-Jensen, Jette; Bowden, Sarah; Caldas, Carlos; Caslake, Muriel; Cupples, L. Adrienne; Cruchaga, Carlos; Czajkowski, Jacek; den Hoed, Marcel; Dunn, Janet A.; Earl, Helena M.; Ehret, Georg B.; Ferrannini, Ele; Ferrieres, Jean; Foltynie, Thomas; Ford, Ian; Forouhi, Nita G.; Gianfagna, Francesco; Gonzalez, Carlos; Grioni, Sara; Hiller, Louise; Jansson, Jan-Håkan; Jørgensen, Marit E.; Jukema, J. Wouter; Kaaks, Rudolf; Kee, Frank; Kerrison, Nicola D.; Key, Timothy J.; Kontto, Jukka; Kote-Jarai, Zsofia; Kraja, Aldi T.; Kuulasmaa, Kari; Kuusisto, Johanna; Linneberg, Allan; Liu, Chunyu; Marenne, Gaëlle; Mohlke, Karen L.; Morris, Andrew P.; Muir, Kenneth; Müller-Nurasyid, Martina; Munroe, Patricia B.; Navarro, Carmen; Nielsen, Sune F.; Nilsson, Peter M.; Nordestgaard, Børge G.; Packard, Chris J.; Palli, Domenico; Panico, Salvatore; Peloso, Gina M.; Perola, Markus; Peters, Annette; Poole, Christopher J.; Quirós, J. Ramón; Rolandsson, Olov; Sacerdote, Carlotta; Salomaa, Veikko; Sánchez, María-José; Sattar, Naveed; Sharp, Stephen J.; Sims, Rebecca; Slimani, Nadia; Smith, Jennifer A.; Thompson, Deborah J.; Trompet, Stella; Tumino, Rosario; van der A, Daphne L.; van der Schouw, Yvonne T.; Virtamo, Jarmo; Walker, Mark; Walter, Klaudia; Abraham, Jean E.; Amundadottir, Laufey T.; Aponte, Jennifer L.; Butterworth, Adam S.; Dupuis, Josée; Easton, Douglas F.; Eeles, Rosalind A.; Erdmann, Jeanette; Franks, Paul W.; Frayling, Timothy M.; Hansen, Torben; Howson, Joanna M. M.; Jørgensen, Torben; Kooner, Jaspal; Laakso, Markku; Langenberg, Claudia; McCarthy, Mark I.; Pankow, James S.; Pedersen, Oluf; Riboli, Elio; Rotter, Jerome I.; Saleheen, Danish; Samani, Nilesh J.; Schunkert, Heribert; Vollenweider, Peter; O'Rahilly, Stephen; Deloukas, Panos; Danesh, John; Goodarzi, Mark O.; Kathiresan, Sekar; Meigs, James B.; Ehm, Margaret G.; Wareham, Nicholas J.; Waterworth, Dawn M.

    2016-01-01

    Regulatory authorities have indicated that new drugs to treat type 2 diabetes (T2D) should not be associated with an unacceptable increase in cardiovascular risk. Human genetics may be able to inform development of antidiabetic therapies by predicting cardiovascular and other health endpoints. We therefore investigated the association of variants in 6 genes that encode drug targets for obesity or T2D with a range of metabolic traits in up to 11,806 individuals by targeted exome sequencing, and follow-up in 39,979 individuals by targeted genotyping, with additional in silico follow up in consortia. We used these data to first compare associations of variants in genes encoding drug targets with the effects of pharmacological manipulation of those targets in clinical trials. We then tested the association those variants with disease outcomes, including coronary heart disease, to predict cardiovascular safety of these agents. A low-frequency missense variant (Ala316Thr;rs10305492) in the gene encoding glucagon-like peptide-1 receptor (GLP1R), the target of GLP1R agonists, was associated with lower fasting glucose and lower T2D risk, consistent with GLP1R agonist therapies. The minor allele was also associated with protection against heart disease, thus providing evidence that GLP1R agonists are not likely to be associated with an unacceptable increase in cardiovascular risk. Our results provide an encouraging signal that these agents may be associated with benefit, a question currently being addressed in randomised controlled trials. Genetic variants associated with metabolic traits and multiple disease outcomes can be used to validate therapeutic targets at an early stage in the drug development process. PMID:27252175

  12. GLP-1 does not not acutely affect insulin sensitivity in healthy man

    DEFF Research Database (Denmark)

    Orskov, L; Holst, J J; Møller, J

    1996-01-01

    Previous studies have suggested that glucagon-like peptide-1 (GLP-1) (7-36 amide) may have the direct effect of increasing insulin sensitivity in healthy man. To evaluate this hypothesis we infused GLP-1 in seven lean healthy men during a hyper insulinaemic (0.8 mU.kg-1.min-1), euglycaemic (5 mmo...

  13. Brainstem GLP-1 signalling contributes to cancer anorexia-cachexia syndrome in the rat.

    Science.gov (United States)

    Borner, Tito; Liberini, Claudia G; Lutz, Thomas A; Riediger, Thomas

    2018-03-15

    The cancer anorexia-cachexia syndrome (CACS) is a frequent and severe condition in cancer patients. Currently, no pharmacological treatment is approved for the therapy of CACS. Centrally, glucagon-like peptide-1 (GLP-1) is expressed in the nucleus tractus solitarii (NTS) and is implicated in malaise, nausea and food aversion. The NTS is reciprocally connected to brain sites implicated in the control of energy balance including the area postrema (AP), which mediates CACS in certain tumour models. Given the role of GLP-1 as a mediator of anorexia under acute sickness conditions, we hypothesized that brainstem GLP-1 signalling might play a role in the mediation of CACS. Using hepatoma tumour-bearing (TB) rats, we first tested whether the chronic delivery of the GLP-1R antagonist exendin-9 (Ex-9) into the fourth ventricle attenuates CACS. Second, we investigated whether a genetic knockdown of GLP-1 expression in the NTS ameliorates CACS. Ex-9 attenuated anorexia, body weight loss, muscle and fat depletion compared to TB controls. Similarly, TB animals with a knockdown of GLP-1 expression in the NTS had higher food intake, reduced body weight loss, and higher lean and fat mass compared to TB controls. Our study identifies brainstem GLP-1 as crucial mediator of CACS in hepatoma TB rats. The GLP-1R represents a promising target against CACS and possibly other forms of disease-related anorexia/cachexia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Combined MSC and GLP-1 Therapy Modulates Collagen Remodeling and Apoptosis following Myocardial Infarction

    Directory of Open Access Journals (Sweden)

    Elizabeth J. Wright

    2016-01-01

    Full Text Available Background. Mesenchymal stem cells (MSCs and glucagon-like peptide-1 (GLP-1 are being tested as treatment strategies for myocardial infarction (MI; however, their mechanisms in the heart are not fully understood. Methods. We examined the effects of MSCs, either native, or engineered to secrete a GLP-1 fusion protein (MSCs ± GLP-1, on human cardiomyocyte apoptosis in vitro. The effect on cardiac remodeling when encapsulated in alginate beads (CellBeads-MSC and CellBeads-MSC + GLP-1 was also evaluated in a pig MI model, whereby pigs were treated with Empty Beads, CellBeads-MSC, or CellBeads-MSC + GLP-1 and sacrificed at one or four weeks following MI. Results. MSC + GLP-1 conditioned media demonstrated antiapoptotic effects on ischaemic human cardiomyocytes in vitro. In vivo, qRT-PCR revealed large changes in the expression of several genes involved in extracellular matrix remodeling, which were altered following MSC ± GLP treatment. After four weeks, infarcted areas were imaged using atomic force microscopy, demonstrating significant alterations between groups in the structure of collagen fibrils and resulting scar. Conclusions. These data demonstrate that MSCs ± GLP-1 exhibit modulatory effects on healing post-MI, affecting both apoptosis and collagen scar formation. These data support the premise that both MSCs and GLP-1 could be beneficial in MI treatment.

  15. Major adverse cardiovascular event reduction with GLP-1 and SGLT2 agents: evidence and clinical potential

    Science.gov (United States)

    Røder, Michael E.

    2017-01-01

    Treatment of patients with type 2 diabetes is directed against treating symptoms of hyperglycemia, minimizing the risk of hypoglycemia, and the risk of microvascular and macrovascular complications. The majority of patients with type 2 diabetes die from cardiovascular or cerebrovascular disease. Future therapies should therefore focus on reducing cardiovascular morbidity in this high-risk population. Glucagon-like peptide-1 receptor agonists (GLP-1RA) and sodium-glucose co-transporter 2 inhibitors (SGLT2-i) are two drug classes with proven antihyperglycemic effect in type 2 diabetes. However, these drugs seem to have other effects such as weight reduction, low risk of hypoglycemia, and blood pressure reduction. Emerging evidence suggests pleiotropic effects, which potentially could be important in reducing cardiovascular risk. Prompted by regulatory authorities demanding cardiovascular outcome trials (CVOTs) assessing the cardiovascular safety of new antihyperglycemic drug candidates, many CVOTs are ongoing and a few of these are finalized. Somewhat surprising recent CVOTs in both drug classes have shown promising data on cardiovascular morbidity and mortality in patients with a very high risk of cardiovascular events. It is uncertain whether this is a class effect of the two drug classes, and it is yet unproven whether long-term cardiovascular benefits of these drugs can be extrapolated to populations at lower risk of cardiovascular disease. The aim of the present review is to give an overview of our current knowledge of the GLP-1RA and SGLT2-i classes, with specific focus on mechanisms of action, effects on cardiovascular risk factors and cardiovascular morbidity and mortality from the CVOTs presently available. The clinical potential of these data is discussed. PMID:29344329

  16. Oral L-Arginine Stimulates GLP-1 Secretion to Improve Glucose Tolerance in Male Mice

    DEFF Research Database (Denmark)

    Clemmensen, Christoffer; Smajilovic, Sanela; Smith, Eric P

    2013-01-01

    Pharmacological and surgical interventions that increase glucagon-like peptide 1 (GLP-1) action are effective to improve glucose homeostasis in type 2 diabetes mellitus. In light of this, nutritional strategies to enhance postprandial GLP-1 secretion, particularly in the context of diet......-induced obesity, may provide an alternative therapeutic approach. Importantly, recent evidence suggests the amino acid l-arginine, a well-known insulin secretagogue, can also stimulate release of GLP-1 from isolated rat intestine. Here we tested the hypothesis that oral l-arginine acts as a GLP-1 secretagogue...... in vivo, to augment postprandial insulin secretion and improve glucose tolerance. To test this, we administered l-arginine or vehicle by oral gavage, immediately prior to an oral glucose tolerance test in lean and diet-induced obese mice. In both lean and obese mice oral l-arginine increased plasma GLP-1...

  17. Molecular mechanisms of lipoapoptosis and metformin protection in GLP-1 secreting cells

    DEFF Research Database (Denmark)

    Kappe, Camilla; Holst, Jens Juul; Zhang, Qimin

    2012-01-01

    Evidence is emerging that elevated serum free fatty acids (hyperlipidemia) contribute to the pathogenesis of type-2-diabetes, and lipotoxicity is observed in many cell types. We recently published data indicating lipotoxic effects of simulated hyperlipidemia also in GLP-1-secreting cells, where...... the antidiabetic drug metformin conferred protection from lipoapoptosis. The aim of the present study was to identify mechanisms involved in mediating lipotoxicity and metformin lipoprotection in GLP-1 secreting cells. These signaling events triggered by simulated hyperlipidemia may underlie reduced GLP-1...... secretion in diabetic subjects, and metformin lipoprotection by metformin could explain elevated plasma GLP-1 levels in diabetic patients on chronic metformin therapy. The present study may thus identify potential molecular targets for increasing endogenous GLP-1 secretion through enhanced viability of GLP...

  18. The regulation of function, growth and survival of GLP-1-producing L-cells

    DEFF Research Database (Denmark)

    Kuhre, Rune Ehrenreich; Holst, Jens Juul; Kappe, Camilla

    2016-01-01

    that regulate the growth, survival and function of these cells are largely unknown. We recently showed that prolonged exposure to high concentrations of the fatty acid palmitate induced lipotoxic effects, similar to those operative in insulin-producing cells, in an in vitro model of GLP-1-producing cells...... absorption and disposal, as well as cell proliferation and survival. In Type 2 Diabetes (T2D) reduced plasma levels of GLP-1 have been observed, and plasma levels of GLP-1, as well as reduced numbers of GLP-1 producing cells, have been correlated to obesity and insulin resistance. Increasing endogenous...... secretion of GLP-1 by selective targeting of the molecular mechanisms regulating secretion from the L-cell has been the focus of much recent research. An additional and promising strategy for enhancing endogenous secretion may be to increase the L-cell mass in the intestinal epithelium, but the mechanisms...

  19. 99mTc Labeled Glucagon-Like Peptide-1-Analogue (99mTc-GLP1) Scintigraphy in the Management of Patients with Occult Insulinoma

    Science.gov (United States)

    Sowa-Staszczak, Anna; Trofimiuk-Müldner, Małgorzata; Stefańska, Agnieszka; Tomaszuk, Monika; Buziak-Bereza, Monika; Gilis-Januszewska, Aleksandra; Jabrocka-Hybel, Agata; Głowa, Bogusław; Małecki, Maciej; Bednarczuk, Tomasz; Kamiński, Grzegorz; Kowalska, Aldona; Mikołajczak, Renata; Janota, Barbara; Hubalewska-Dydejczyk, Alicja

    2016-01-01

    Introduction The aim of this study was to assess the utility of [Lys40(Ahx-HYNIC-99mTc/EDDA)NH2]-exendin-4 scintigraphy in the management of patients with hypoglycemia, particularly in the detection of occult insulinoma. Materials and Methods Forty patients with hypoglycemia and increased/confusing results of serum insulin and C-peptide concentration and negative/inconclusive results of other imaging examinations were enrolled in the study. In all patients GLP-1 receptor imaging was performed to localise potential pancreatic lesions. Results Positive results of GLP-1 scintigraphy were observed in 28 patients. In 18 patients postsurgical histopathological examination confirmed diagnosis of insulinoma. Two patients had contraindications to the surgery, one patient did not want to be operated. One patient, who presented with postprandial hypoglycemia, with positive result of GLP-1 imaging was not qualified for surgery and is in the observational group. Eight patients were lost for follow up, among them 6 patients with positive GLP-1 scintigraphy result. One patient with negative scintigraphy was diagnosed with malignant insulinoma. In two patients with negative scintigraphy Munchausen syndrome was diagnosed (patients were taking insulin). Other seven patients with negative results of 99mTcGLP-1 scintigraphy and postprandial hypoglycemia with C-peptide and insulin levels within the limits of normal ranges are in the observational group. We would like to mention that 99mTc-GLP1-SPECT/CT was also performed in 3 pts with nesidioblastosis (revealing diffuse tracer uptake in two and a focal lesion in one case) and in two patients with malignant insulinoma (with the a focal uptake in the localization of a removed pancreatic headin one case and negative GLP-1 1 scintigraphy in the other patient). Conclusions 99mTc-GLP1-SPECT/CT could be helpful examination in the management of patients with hypoglycemia enabling proper localization of the pancreatic lesion and effective

  20. GLP-1 and Calcitonin Concentration in Humans: Lack of Evidence of Calcitonin Release from Sequential Screening in over 5000 Subjects with Type 2 Diabetes or Nondiabetic Obese Subjects Treated with the Human GLP-1 Analog, Liraglutide

    DEFF Research Database (Denmark)

    Hegedüs, Laszlo; Moses, Alan C; Zdravkovic, Milan

    2011-01-01

    to the GLP-1 receptor agonist liraglutide in subjects with type 2 diabetes mellitus or nondiabetic obese subjects. Methods: Unstimulated serum CT concentrations were measured at 3-month intervals for no more than 2 yr in a series of trials in over 5000 subjects receiving liraglutide or control therapy....... Results: Basal mean CT concentrations were at the low end of normal range in all treatment groups and remained low throughout the trials. At 2 yr, estimated geometric mean values were no greater than 1.0 ng/liter, well below upper normal ranges for males and females. Proportions of subjects whose CT...

  1. GLP-1-Based Therapies Have No Microvascular Effects in Type 2 Diabetes Mellitus: An Acute and 12-Week Randomized, Double-Blind, Placebo-Controlled Trial.

    Science.gov (United States)

    Smits, Mark M; Tonneijck, Lennart; Muskiet, Marcel H A; Hoekstra, Trynke; Kramer, Mark H H; Diamant, Michaela; Serné, Erik H; van Raalte, Daniël H

    2016-10-01

    To assess the effects of glucagon-like peptide (GLP)-1-based therapies (ie, GLP-1 receptor agonists and dipeptidyl peptidase-4 inhibitors) on microvascular function in patients with type 2 diabetes mellitus. We studied 57 patients with type 2 diabetes mellitus (mean±SD age: 62.8±6.9 years; body mass index: 31.8±4.1 kg/m(2); HbA1c [glycated hemoglobin] 7.3±0.6%) in an acute and 12-week randomized, placebo-controlled, double-blind trial conducted at the Diabetes Center of the VU University Medical Center. In the acute study, the GLP-1 receptor agonist exenatide (therapeutic concentrations) or placebo (saline 0.9%) was administered intravenously. During the 12-week study, patients received the GLP-1 receptor agonist liraglutide (1.8 mg daily), the dipeptidyl peptidase-4 inhibitor sitagliptin (100 mg daily), or matching placebos. Capillary perfusion was assessed by nailfold skin capillary videomicroscopy and vasomotion by laser Doppler fluxmetry, in the fasting state and after a high-fat mixed meal. In neither study, treatment affected fasting or postprandial capillary perfusion compared with placebo (P>0.05). In the fasting state, acute exenatide infusion increased neurogenic vasomotion domain power, while reducing myogenic domain power (both P12-week study, no effects on vasomotion were observed. Despite modest changes in vasomotion, suggestive of sympathetic nervous system activation and improved endothelial function, acute exenatide infusion does not affect skin capillary perfusion in type 2 diabetes mellitus. Twelve-week treatment with liraglutide or sitagliptin has no effect on capillary perfusion or vasomotion in these patients. Our data suggest that the effects of GLP-1-based therapies on glucose are not mediated through microvascular responses. © 2016 American Heart Association, Inc.

  2. Direct effects of glucose, insulin, GLP-1, and GIP on bulbospinal neurons in the rostral ventrolateral medulla in neonatal wistar rats.

    Science.gov (United States)

    Oshima, Naoki; Onimaru, Hiroshi; Matsubara, Hidehito; Uchida, Takahiro; Watanabe, Atsushi; Imakiire, Toshihiko; Nishida, Yasuhiro; Kumagai, Hiroo

    2017-03-06

    Although patients with diabetes mellitus (DM) often exhibit hypertension, the mechanisms responsible for this correlation are not well known. We hypothesized that the bulbospinal neurons in the rostral ventrolateral medulla (RVLM) are affected by the levels of glucose, insulin, or incretins (glucagon like peptide-1 [GLP-1] or glucose-dependent insulinotropic peptide [GIP]) in patients with DM. To investigate whether RVLM neurons are activated by glucose, insulin, GLP-1, or GIP, we examined changes in the membrane potentials of bulbospinal RVLM neurons using whole-cell patch-clamp technique during superfusion with various levels of glucose or these hormones in neonatal Wistar rats. A brainstem-spinal cord preparation was used for the experiments. A low level of glucose stimulated bulbospinal RVLM neurons. During insulin superfusion, almost all the RVLM neurons were depolarized, while during GLP-1 or GIP superfusion, almost all the RVLM neurons were hyperpolarized. Next, histological examinations were performed to examine transporters for glucose and receptors for insulin, GLP-1, and GIP on RVLM neurons. Low-level glucose-depolarized RVLM neurons exhibited the presence of glucose transporter 3 (GLUT3). Meanwhile, insulin-depolarized, GLP-1-hyperpolarized, and GIP-hyperpolarized RVLM neurons showed each of the respective specific receptor. These results indicate that a low level of glucose stimulates bulbospinal RVLM neurons via specific transporters on these neurons, inducing hypertension. Furthermore, an increase in insulin or a reduction in incretins may also activate the sympathetic nervous system and induce hypertension by activating RVLM neurons via their own receptors. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  3. GLP-1 and exendin-4 for imaging endocrine pancreas. A review. Labelled glucagon-like peptide-1 analogues: past, present and future

    International Nuclear Information System (INIS)

    Hubalewska-Dydejczyk, A.; Sowa-Staszczak, A.; Tomaszuk, M.; Stefańska, A.

    2015-01-01

    Glucagon-like peptide 1 (GLP-1) receptors expression has been found on many types of cancer cells. In case of benign insulinoma the density of those receptors is even higher than the density of somatostatin receptors. This article presents the results of clinical trials proving the utility of GLP-1 receptors imaging. Scintigraphy or positron emission tomography with the use of GLP-1 analogues labelled with appropriate radioisotopes ( 111I n, 99m Tc, 68 Ga, 18 F or 64 Cu) seem to be superior compared with other available techniques in diagnosis of hardly detectable benign insulinoma. While surgery is the only effective therapy for insulinoma patients, therefore proper preoperative localization of the tumor allows sparing operation. Glucagon-like peptide 1 receptors might become also a target for imaging of other tumors such as gastrinoma, pheochromocytoma and medullary thyroid cancer (MTC), which also were shown to over express this type of receptors. However, studies with larger groups of patients are required to prove the clinical usefulness of this indication. Moreover GLP-1 receptor imaging seems to be a potential tool to evaluate pancreatic beta cell mass (BCM). It may be useful in the early diagnosis of beta cell loss in preclinical phases of diabetes. The panceratic beta cells imaging may influence the prophylaxis of diabetes and management of diabetic patients. Presented results of clinical trials prove that glucagon-like peptide 1 receptor imaging might become helpful diagnostic strategy particularly in case of patients with benign insulinoma tumors, but also patients with gastrinoma, pheochromocytoma, medullary thyroid cancer and diabetes.

  4. GLP-1 analog raises glucose transport capacity of blood-brain barrier in Alzheimer's disease

    DEFF Research Database (Denmark)

    Gejl, M.; Brock, B.; Egefjord, L.

    2017-01-01

    transport capacity (Tmax) with [18F]FDG (FDG) (ClinicalTrials.gov NCT01469351). Results: In both groups, the Tmax estimates declined in proportion to the duration of AD. The GLP-1 analog treatment very significantly (P cerebral cortex as a whole compared...... and degeneration. Hypothesis: The incretin hormone GLP-1 prevents the decline of the cerebral metabolic rate of glucose that signifies cognitive impairment, synaptic dysfunction, and disease evolution in AD, and GLP-1 may directly activate GLUT1 transport in brain capillary endothelium. For this reason, we here...

  5. The physiological role of the brain GLP-1 system in stress

    OpenAIRE

    Holt, M. K.; Trapp, S.

    2016-01-01

    Glucagon-like peptide-1 (GLP-1) within the brain is a potent regulator of food intake and most studies have investigated the anorexic effects of central GLP-1. A range of brain regions have now been found to be involved in GLP-1 mediated anorexia, including some which are not traditionally associated with appetite regulation. However, a change in food intake can be indicative of not only reduced energy demand, but also changes in the organism's motivation to eat following stressful stimuli. I...

  6. GLP-1 Amidation Efficiency Along the Length of the Intestine in Mice, Rats and Pigs and in GLP-1 Secreting Cell Lines

    DEFF Research Database (Denmark)

    Kuhre, Rune Ehrenreich; Albrechtsen, Nicolai Jacob Wewer; Windeløv, Johanne Agerlin

    2014-01-01

    and whether this varied with the six different locations. We also analyzed the amidation in 3 GLP-1 secreting cell lines (GLUTag, NCI-H716 and STC-1). To our surprise there were marked differences between the 3 species with respect to the concentration of GLP-1 in gut. In the mouse, concentrations increased...... sites, whereas rats and pigs on average had around 2.5 and 4 times higher levels of amidated compared to non-amidated GLP-1, although the ratio varied depending upon the location. GLUTag, NCI-H716 and STC-1 cells all exhibited partial amidation with 2-4 times higher levels of amidated compared to non...

  7. Direct effects of exendin-(9,39) and GLP-1-(9,36)amide on insulin action, β-cell function, and glucose metabolism in nondiabetic subjects.

    Science.gov (United States)

    Sathananthan, Matheni; Farrugia, Luca P; Miles, John M; Piccinini, Francesca; Dalla Man, Chiara; Zinsmeister, Alan R; Cobelli, Claudio; Rizza, Robert A; Vella, Adrian

    2013-08-01

    Exendin-(9,39) is a competitive antagonist of glucagon-like peptide-1 (GLP-1) at its receptor. However, it is unclear if it has direct and unique effects of its own. We tested the hypothesis that exendin-(9,39) and GLP-1-(9,36)amide have direct effects on hormone secretion and β-cell function as well as glucose metabolism in healthy subjects. Glucose containing [3-(3)H]glucose was infused to mimic the systemic appearance of glucose after a meal. Saline, GLP-1-(9,36)amide, or exendin-(9,39) at 30 pmol/kg/min (Ex 30) or 300 pmol/kg/min (Ex 300) were infused in random order on separate days. Integrated glucose concentrations were slightly but significantly increased by exendin-(9,39) (365 ± 43 vs. 383 ± 35 vs. 492 ± 49 vs. 337 ± 50 mmol per 6 h, saline, Ex 30, Ex 300, and GLP-1-[9,36]amide, respectively; P = 0.05). Insulin secretion did not differ among groups. However, insulin action was lowered by exendin-(9,39) (25 ± 4 vs. 20 ± 4 vs. 18 ± 3 vs. 21 ± 4 10(-4) dL/kg[min per μU/mL]; P = 0.02), resulting in a lower disposition index (DI) during exendin-(9,39) infusion (1,118 ± 118 vs. 816 ± 83 vs. 725 ± 127 vs. 955 ± 166 10(-14) dL/kg/min(2) per pmol/L; P = 0.003). Endogenous glucose production and glucose disappearance did not differ significantly among groups. We conclude that exendin-(9,39), but not GLP-1-(9,36)amide, decreases insulin action and DI in healthy humans.

  8. Co-culture of clonal beta cells with GLP-1 and glucagon-secreting cell line impacts on beta cell insulin secretion, proliferation and susceptibility to cytotoxins.

    Science.gov (United States)

    Green, Alastair D; Vasu, Srividya; Moffett, R Charlotte; Flatt, Peter R

    2016-06-01

    We investigated the direct effects on insulin releasing MIN6 cells of chronic exposure to GLP-1, glucagon or a combination of both peptides secreted from GLUTag L-cell and αTC1.9 alpha-cell lines in co-culture. MIN6, GLUTag and αTC1.9 cell lines exhibited high cellular hormone content and release of insulin, GLP-1 and glucagon, respectively. Co-culture of MIN6 cells with GLUTag cells significantly increased cellular insulin content, beta-cell proliferation, insulin secretory responses to a range of established secretogogues and afforded protection against exposure cytotoxic concentrations of glucose, lipid, streptozotocin or cytokines. Benefits of co-culture of MIN6 cells with αTC1.9 alphacells were limited to enhanced beta-cell proliferation with marginal positive actions on both insulin secretion and cellular protection. In contrast, co-culture of MIN6 with GLUTag cells plus αTC1.9 cells, markedly enhanced both insulin secretory responses and protection against beta-cell toxins compared with co-culture with GLUTag cells alone. These data indicate important long-term effects of conjoint GLP-1 and glucagon exposure on beta-cell function. This illustrates the possible functional significance of alpha-cell GLP-1 production as well as direct beneficial effects of dual agonism at beta-cell GLP-1 and glucagon receptors. Copyright © 2016 Elsevier B.V. and Société française de biochimie et biologie Moléculaire (SFBBM). All rights reserved.

  9. Secretion of glucagon-like peptide-1 (GLP-1) in type 2 diabetes

    DEFF Research Database (Denmark)

    Nauck, M A; Vardarli, I; Deacon, C F

    2011-01-01

    The incretin hormones gastric inhibitory polypeptide and especially glucagon-like peptide (GLP) have an important physiological function in augmenting postprandial insulin secretion. Since GLP-1 may play a role in the pathophysiology and treatment of type 2 diabetes, assessment of meal-related GLP......-1 secretory responses in type 2 diabetic patients vs healthy individuals is of great interest. A common view states that GLP-1 secretion in patients with type 2 diabetes is deficient and that this applies to a lesser degree in individuals with impaired glucose tolerance. Such a deficiency...... with and without diabetes after oral glucose and mixed meals. Our analysis does not support the contention of a generalised defect in nutrient-related GLP-1 secretory responses in type 2 diabetes patients. Rather, factors are identified that may determine individual incretin secretory responses and explain some...

  10. Preserved GLP-1 effects in a diabetic patient with Cushing's disease

    DEFF Research Database (Denmark)

    Ritzel, R A; Kleine, N; Holst, Jens Juul

    2007-01-01

    CONTEXT: A patient with diabetes mellitus, who participated in a study with intravenous administration of GLP-1, was later found to have Cushing's disease (markedly elevated 24 h urinary cortisol excretion and inadequate suppression of fasting cortisol with 2 mg dexamethasone). His diabetic state...... mellitus due to Cushing's disease with GLP-1 actions in typical type 2 diabetes. DESIGN AND METHODS: GLP-1 (1.2 pmol/kg/min) and placebo had been infused into ten patients with diabetes mellitus over 4 h in the fasting state. The results from the patient with Cushing's disease (C) were compared to the data...... with Cushing's disease compared to those with type 2 diabetes. CONCLUSIONS: The insulinotropic, glucagonostatic and glucose-lowering actions of GLP-1 in a patient with diabetes mellitus due to cortisol excess were similar to actions in typical type 2 diabetes. Therefore incretin mimetics might be a novel...

  11. Neuroprotective effects of (Val8)GLP-1-Glu-PAL in the MPTP Parkinson's disease mouse model

    OpenAIRE

    Zhang, YanFang; Chen, YiMei; Li, Lin; Holscher, Christian

    2015-01-01

    Glucagon-like peptide 1 (GLP-1) is a hormone and a growth factor. GLP-1 mimetics are currently on the market as treatments for type 2 diabetes. They also have shown neuroprotective properties in animal models of neurodegenerative disorders. In addition, the GLP-1 mimetic exendin-4 has shown protective effects in animal models of Parkinson's disease (PD), and a first clinical trial in PD patients showed promising results. (Val8)GLP-1-glu-PAL is a new GLP-1 analogue which has a longer biologica...

  12. GLP-1 and GIP are colocalized in a subset of endocrine cells in the small intestine

    DEFF Research Database (Denmark)

    Mortensen, Kristine; Christensen, Louise Lundby; Holst, Jens Juul

    2003-01-01

    BACKGROUND: The incretin hormones GIP and GLP-1 are thought to be produced in separate endocrine cells located in the proximal and distal ends of the mammalian small intestine, respectively. METHODS AND RESULTS: Using double immunohistochemistry and in situ hybridization, we found that GLP-1 was ....... CONCLUSIONS: Our results provide a morphological basis to suggest simultaneous, rather than sequential, secretion of these hormones by postprandial luminal stimulation....

  13. Bariatric surgery may reduce the risk of Alzheimer's diseases through GLP-1 mediated neuroprotective effects.

    Science.gov (United States)

    Keshava, Hari B; Mowla, Ashkan; Heinberg, Leslie J; Schauer, Philip R; Brethauer, Stacy A; Aminian, Ali

    2017-07-01

    Obesity and diabetes are associated with deficits in multiple neurocognitive domains and increased risk for dementia. Over the last two decades, there has been a significant increase in bariatric and metabolic surgery worldwide, driven by rising intertwined pandemics of obesity and diabetes, along with improvement in surgical techniques. Patients undergoing bariatric surgery achieve a significant decrease in their excess weight and a multitude of sequela associated with obesity, diabetes, and metabolic syndrome. Glucagon-like peptide 1 (GLP-1) is an intestinal peptide that has been implicated as one of the weight loss-independent mechanisms in how bariatric surgery affects type 2 diabetes. GLP-1 improves insulin secretion, inhibits apoptosis and induce pancreatic islet neogenesis, promotes satiety, and can regulate heart rate and blood pressure. Moreover, numerous studies have demonstrated potential neuroprotective and neurotrophic effects of GLP-1. Increased GLP-1 activity has been shown to increase cortical activity, promote neuronal growth, and inhibit neuronal degeneration. Specifically, in experimental studies on Alzheimer's disease, GLP-1 decreases amyloid deposition and neurofibrillary tangles. Furthermore, recent studies have also suggested that GLP-1 based therapies, new class of antidiabetic drugs, have favorable effects on neurodegenerative disorders such as Alzheimer's disease. We present a hypothesis that bariatric surgery can help delay or even prevent the onset of Alzheimer's disease in long-term by increasing the levels of GLP-1. This hypothesis has a potential for many studies from basic science projects to large population studies to fully understand the neurological and cognitive consequences of bariatric surgery and associated rise in GLP-1. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Myocardial regeneration in adriamycin cardiomyopathy by nuclear expression of GLP1 using ultrasound targeted microbubble destruction

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shuyuan [Baylor Research Institute, Baylor University Medical Center, 3812 Elm Street, Dallas, TX (United States); Chen, Jiaxi [The University of Texas Southwestern Medical Center at Dallas, Medical School, 5235 Harry Hine Blvd., Dallas, TX (United States); Huang, Pintong [Department of Ultrasonography, The 2nd Affiliated Hospital of Zhejiang University College of Medicine, Hangzhou, Zhejiang Province (China); Meng, Xing-Li; Clayton, Sandra; Shen, Jin-Song [Baylor Research Institute, Baylor University Medical Center, 3812 Elm Street, Dallas, TX (United States); Grayburn, Paul A., E-mail: paulgr@baylorhealth.edu [Baylor Research Institute, Baylor University Medical Center, 3812 Elm Street, Dallas, TX (United States); Department of Internal Medicine, Division of Cardiology, Baylor Heart and Vascular Institute, Baylor University Medical Center, 621 N. Hall St, Suite H030, Dallas, TX (United States)

    2015-03-20

    Recently GLP-1 was found to have cardioprotective effects independent of those attributable to tight glycemic control. Methods and results: We employed ultrasound targeted microbubble destruction (UTMD) to deliver piggybac transposon plasmids encoding the GLP-1 gene with a nuclear localizing signal to rat hearts with adriamycin cardiomyopathy. After a single UTMD treatment, overexpression of transgenic GLP-1 was found in nuclei of rat heart cells with evidence that transfected cardiac cells had undergone proliferation. UTMD-GLP-1 gene therapy restored LV mass, fractional shortening index, and LV posterior wall diameter to nearly normal. Nuclear overexpression of GLP-1 by inducing phosphorylation of FoxO1-S256 and translocation of FoxO1 from the nucleus to the cytoplasm significantly inactivated FoxO1 and activated the expression of cyclin D1 in nuclei of cardiac muscle cells. Reversal of adriamycin cardiomyopathy appeared to be mediated by dedifferentiation and proliferation of nuclear FoxO1-positive cardiac muscle cells with evidence of embryonic stem cell markers (OCT4, Nanog, SOX2 and c-kit), cardiac early differentiation markers (NKX2.5 and ISL-1) and cellular proliferation markers (BrdU and PHH3) after UTMD with GLP-1 gene therapy. Conclusions: Intranuclear myocardial delivery of the GLP-1gene can reverse established adriamycin cardiomyopathy by stimulating myocardial regeneration. - Highlights: • The activation of nuclear FoxO1 in cardiac muscle cells associated with adriamycin cardiomyopathy. • Myocardial nuclear GLP-1 stimulates myocardial regeneration and reverses adriamycin cardiomyopathy. • The process of myocardial regeneration associated with dedifferentiation and proliferation.

  15. Myocardial regeneration in adriamycin cardiomyopathy by nuclear expression of GLP1 using ultrasound targeted microbubble destruction

    International Nuclear Information System (INIS)

    Chen, Shuyuan; Chen, Jiaxi; Huang, Pintong; Meng, Xing-Li; Clayton, Sandra; Shen, Jin-Song; Grayburn, Paul A.

    2015-01-01

    Recently GLP-1 was found to have cardioprotective effects independent of those attributable to tight glycemic control. Methods and results: We employed ultrasound targeted microbubble destruction (UTMD) to deliver piggybac transposon plasmids encoding the GLP-1 gene with a nuclear localizing signal to rat hearts with adriamycin cardiomyopathy. After a single UTMD treatment, overexpression of transgenic GLP-1 was found in nuclei of rat heart cells with evidence that transfected cardiac cells had undergone proliferation. UTMD-GLP-1 gene therapy restored LV mass, fractional shortening index, and LV posterior wall diameter to nearly normal. Nuclear overexpression of GLP-1 by inducing phosphorylation of FoxO1-S256 and translocation of FoxO1 from the nucleus to the cytoplasm significantly inactivated FoxO1 and activated the expression of cyclin D1 in nuclei of cardiac muscle cells. Reversal of adriamycin cardiomyopathy appeared to be mediated by dedifferentiation and proliferation of nuclear FoxO1-positive cardiac muscle cells with evidence of embryonic stem cell markers (OCT4, Nanog, SOX2 and c-kit), cardiac early differentiation markers (NKX2.5 and ISL-1) and cellular proliferation markers (BrdU and PHH3) after UTMD with GLP-1 gene therapy. Conclusions: Intranuclear myocardial delivery of the GLP-1gene can reverse established adriamycin cardiomyopathy by stimulating myocardial regeneration. - Highlights: • The activation of nuclear FoxO1 in cardiac muscle cells associated with adriamycin cardiomyopathy. • Myocardial nuclear GLP-1 stimulates myocardial regeneration and reverses adriamycin cardiomyopathy. • The process of myocardial regeneration associated with dedifferentiation and proliferation

  16. Altered glucose metabolism after bariatric surgery: What's GLP-1 got to do with it?

    Science.gov (United States)

    Smith, Eric P; Polanco, Georgina; Yaqub, Abid; Salehi, Marzieh

    2018-06-01

    Bariatric surgery is an effective treatment for obesity. The two widely performed weight-loss procedures, Roux-en-Y gastric bypass (GB) and sleeve gastrectomy (SG), alter postprandial glucose pattern and enhance gut hormone secretion immediately after surgery before significant weight loss. This weight-loss independent glycemic effects of GB has been attributed to an accelerated nutrient transit from stomach pouch to the gut and enhanced secretion of insulinotropic gut factors; in particular, glucagon-like peptide-1 (GLP-1). Meal-induced GLP-1 secretion is as much as tenfold higher in patients after GB compared to non-surgical individuals and inhibition of GLP-1 action during meals reduces postprandial hyperinsulinemia after GB two to three times more than that in persons without surgery. Moreover, in a subgroup of patients with the late complication of postprandial hyperinsulinemic hypoglycemia after GB, GLP1R blockade reverses hypoglycemia by reducing meal stimulated insulin secretion. The role of enteroinsular axis activity after SG, an increasingly popular alternative to GB, is less understood but, similar to GB, SG accelerates nutrient delivery to the intestine, improves glucose tolerance, and increases postprandial GLP-1 secretion. This review will focus on the current evidence for and against the role of GLP-1 on glycemic effects of GB and will also highlight differences between GB and SG. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. The Effect of Exogenous GLP-1 on Food Intake is Lost in Male Truncally Vagotomized Subjects with Pyloroplasty

    DEFF Research Database (Denmark)

    Plamboeck, Astrid; Veedfald, Simon; Deacon, Carolyn F

    2013-01-01

    . Subjects received GLP-1 (7-36 amide) or saline infusions during and after a standardized liquid mixed meal and a subsequent ad libitum meal. Despite no effect on appetite sensations, GLP-1 significantly reduced ad libitum food intake in the control group, but had no effect in the vagotomized group. Gastric...... with pyloroplasty impairs the effects of exogenous GLP-1 on food intake, gastric emptying, insulin and glucagon secretion, suggesting that intact vagal innervation may be important for GLP-1's actions....... emptying was accelerated in vagotomized subjects and was decreased by GLP-1 in controls but not in vagotomized subjects. Postprandial glucose levels were reduced by the same percentage by GLP-1 in both groups. Peak postprandial GLP-1 levels were ~5-fold higher in the vagotomized subjects. Insulin secretion...

  18. The antagonistic metabolite of GLP-1, GLP-1 (9-36)amide, does not influence gastric emptying and hunger sensations in man

    DEFF Research Database (Denmark)

    Nagell, Carl Frederic; Pedersen, Jan F; Holst, Jens Juul

    2007-01-01

    and antral emptying of a meal. MATERIAL AND METHODS: Six healthy volunteers were tested in a double-blind, placebo-controlled fashion. Antral emptying of a liquid meal and hunger ratings were determined using ultrasound technology and visual analogue scale scoring during infusions of saline or GLP-1 (9...

  19. GLP-1 and GIP Levels in Patients With Hyperthyroidism: The Effect of Antithyroid Treatment.

    Science.gov (United States)

    Cira, Duygu Kalkan; Sari, Ramazan; Ozdem, Sebahat; Yilmaz, Nusret; Bozkurt, Selen

    2017-08-01

    Incretin hormones (glucagon-like peptide-1 [GLP-1] and gastric inhibitory polypeptide [GIP]) may play a role in the development of glucose intolerance and hyperglycemia in patients with hyperthyroidism. We aimed to assess both incretin levels and treatment-induced changes in incretin levels in those with hyperthyroidism. A total of 24 subjects (12 with hyperthyroidism and 12 healthy) were enrolled in the study. Oral glucose tolerance test was performed and serum glucose, insulin GLP1, and GIP levels were evaluated at 0 (baseline), 30, 60, 90, and 120 minutes using ELISA. Measurements were repeated after euthyroidism was reached in subjects with hyperthyroidism. The baseline glucose level was higher in those with hyperthyroidism compared with controls ( P = 0.03). GLP-1 and GIP responses to oral glucose load did not differ significantly between those with hyperthyroidism and controls. Peak GLP-1 and GIP levels were reached in both groups at 60 and 90 minutes, respectively. Areas under the curve (AUCs) for GLP1 and GIP were similar in those with hyperthyroidism and controls. Although GLP-1 and GIP levels did not change before and after antithyroid treatment in subjects with hyperthyroidism, time to peak GLP-1 and GIP levels were reached at 30 minutes after euthyroid state was achieved. Reversal of hyperthyroid to euthyroid status did not induce significant changes in AUCs for incretins. The findings of the present study suggest that the total incretin response to oral glucose load is preserved in patients with hypertyhroidism, but peak incretin responses may change after achieving euthyroid state.

  20. Small-molecule agonists for the glucagon-like peptide 1 receptor

    DEFF Research Database (Denmark)

    Knudsen, Lotte Bjerre; Kiel, Dan; Teng, Min

    2007-01-01

    and independent agonists. Potency of GLP-1 was not changed by the allosteric agonists, but affinity of GLP-1 for the receptor was increased. The most potent compound identified stimulates glucose-dependent insulin release from normal mouse islets but, importantly, not from GLP-1 receptor knockout mice. Also...

  1. Ligand binding and activation mechanism og the glucagon-like peptide-1 receptor

    DEFF Research Database (Denmark)

    Underwood, Christina Rye

    GLP-1R interacts with receptor agonists. The thesis includes four studies, which investigate different aspects of these interactions. The first study elucidates GLP-1 binding to the extracellular domain of GLP-1R (ECD) (Study I), whereas the second study identifies receptor domains important for small...

  2. The effects of TNF-α on GLP-1-stimulated plasma glucose kinetics

    DEFF Research Database (Denmark)

    Lehrskov-Schmidt, Louise; Lehrskov-Schmidt, Lars; Nielsen, Signe T

    2015-01-01

    levels impairs GLP-1's effects on glucose metabolism. Design: Randomized, controlled, cross-over trial. Setting: Hospital clinical research laboratory. Participants: Twelve healthy males (age 24±3 y; BMI 22.9±1.3 kg/m(2)). Interventions: Following an overnight fast, either saline (0.9%) or recombinant......Context: GLP-1 analogues have recently been promoted as anti-hyperglycemic agents in critically ill patients with systemic inflammation, but the effects of TNF-α on glucose metabolism during GLP-1 administration are unknown. Objective: To determine whether infusion of TNF-α at high physiological...... human TNF-α (1000 ng/m(2)/h) was infused from t = 0-6 hours. At t = 2 hours, GLP-1 infusion (0.5 pmol/kg/min) began. From t = 4-6 hours, the GLP-1 infusion rate was increased to 1.2 pmol/kg/min. Plasma glucose was clamped at 5 mmol/L throughout via a variable-rate 20% dextrose infusion. Trials were 7...

  3. GIP does not potentiate the antidiabetic effects of GLP-1 in hyperglycemic patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Mentis, Nikolaos; Vardarli, Irfan; Köthe, Lars D

    2011-01-01

    OBJECTIVE The incretin glucagon-like peptide 1 (GLP-1) exerts insulinotropic activity in type 2 diabetic patients, whereas glucose-dependent insulinotropic polypeptide (GIP) no longer does. We studied whether GIP can alter the insulinotropic or glucagonostatic activity of GLP-1 in type 2 diabetic...... patients. RESEARCH DESIGN AND METHODS Twelve patients with type 2 diabetes (nine men and three women; 61 ± 10 years; BMI 30.0 ± 3.7 kg/m2; HbA1c 7.3 ± 1.5%) were studied. In randomized order, intravenous infusions of GLP-1(7-36)-amide (1.2 pmol · kg-1 · min-1), GIP (4 pmol · kg-1 · min-1), GLP-1 plus GIP...... the insulinotropic and glucose-lowering effects of GLP-1 in type 2 diabetes. Rather, the suppression of glucagon by GLP-1 is antagonized by GIP....

  4. Fructose stimulates GLP-1 but not GIP secretion in mice, rats, and humans

    DEFF Research Database (Denmark)

    Kuhre, Rune Ehrenreich; Gribble, Fiona M; Hartmann, Bolette

    2014-01-01

    Nutrients often stimulate gut hormone secretion, but the effects of fructose are incompletely understood. We studied the effects of fructose on a number of gut hormones with particular focus on glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). In healthy humans......, fructose intake caused a rise in blood glucose and plasma insulin and GLP-1, albeit to a lower degree than isocaloric glucose. Cholecystokinin secretion was stimulated similarly by both carbohydrates, but neither peptide YY3-36 nor glucagon secretion was affected by either treatment. Remarkably, while...... glucose potently stimulated GIP release, fructose was without effect. Similar patterns were found in the mouse and rat, with both fructose and glucose stimulating GLP-1 secretion, whereas only glucose caused GIP secretion. In GLUTag cells, a murine cell line used as model for L cells, fructose...

  5. Emerging technologies to achieve oral delivery of GLP-1 and GLP-1 analogs for treatment of type 2 diabetes mellitus (T2DM

    Directory of Open Access Journals (Sweden)

    Shengwu Ma

    2017-04-01

    Full Text Available Glucagon-like peptide-1 (GLP-1 is a gastrointestinal (GI peptide hormone that stimulates insulin secretion, gene expression and β-cell proliferation, representing a potentially novel and promising therapeutic agent for the treatment of T2DM. DPP-IV-resistant, long-acting GLP-1 analogs have already been approved by FDA as injectable drugs for treating patients with T2DM. Oral delivery of therapeutic peptides and proteins would be preferred owing to advantages of lower cost, ease of administration and greater patient adherence. However, oral delivery of proteins can be affected by rapid enzymatic degradation in the GI tract and poor penetration across the intestinal membrane, which may require amounts that exceed practical consideration. Various production strategies have been explored to overcome challenges associated with the oral delivery of therapeutic peptides and proteins. The goal of this review is to provide an overview of the current state of progress made towards the oral delivery of GLP-1 and its analogs in the treatment of T2DM, with special emphasis on the development of plant and food-grade bacterial delivery systems. Recently, genetically engineered plants and food-grade bacteria have been increasingly explored as novel carrier systems for the oral delivery of peptide and protein drugs. These have a largely unexplored potential to serve both as an expression system and as a delivery vehicle for clinically relevant, cost effective therapeutics. As such, they hold great promise for human biopharmaceuticals and novel therapies against various diseases.

  6. Molecular Characterisation of Small Molecule Agonists Effect on the Human Glucagon Like Peptide-1 Receptor Internalisation.

    Science.gov (United States)

    Thompson, Aiysha; Stephens, Jeffrey W; Bain, Stephen C; Kanamarlapudi, Venkateswarlu

    2016-01-01

    The glucagon-like peptide receptor (GLP-1R), which is a G-protein coupled receptor (GPCR), signals through both Gαs and Gαq coupled pathways and ERK phosphorylation to stimulate insulin secretion. The aim of this study was to determine molecular details of the effect of small molecule agonists, compounds 2 and B, on GLP-1R mediated cAMP production, intracellular Ca2+ accumulation, ERK phosphorylation and its internalisation. In human GLP-1R (hGLP-1R) expressing cells, compounds 2 and B induced cAMP production but caused no intracellular Ca2+ accumulation, ERK phosphorylation or hGLP-1R internalisation. GLP-1 antagonists Ex(9-39) and JANT-4 and the orthosteric binding site mutation (V36A) in hGLP-1R failed to inhibit compounds 2 and B induced cAMP production, confirming that their binding site distinct from the GLP-1 binding site on GLP-1R. However, K334A mutation of hGLP-1R, which affects Gαs coupling, inhibited GLP-1 as well as compounds 2 and B induced cAMP production, indicating that GLP-1, compounds 2 and B binding induce similar conformational changes in the GLP-1R for Gαs coupling. Additionally, compound 2 or B binding to the hGLP-1R had significantly reduced GLP-1 induced intracellular Ca2+ accumulation, ERK phosphorylation and hGLP-1R internalisation. This study illustrates pharmacology of differential activation of GLP-1R by GLP-1 and compounds 2 and B.

  7. Molecular Characterisation of Small Molecule Agonists Effect on the Human Glucagon Like Peptide-1 Receptor Internalisation.

    Directory of Open Access Journals (Sweden)

    Aiysha Thompson

    Full Text Available The glucagon-like peptide receptor (GLP-1R, which is a G-protein coupled receptor (GPCR, signals through both Gαs and Gαq coupled pathways and ERK phosphorylation to stimulate insulin secretion. The aim of this study was to determine molecular details of the effect of small molecule agonists, compounds 2 and B, on GLP-1R mediated cAMP production, intracellular Ca2+ accumulation, ERK phosphorylation and its internalisation. In human GLP-1R (hGLP-1R expressing cells, compounds 2 and B induced cAMP production but caused no intracellular Ca2+ accumulation, ERK phosphorylation or hGLP-1R internalisation. GLP-1 antagonists Ex(9-39 and JANT-4 and the orthosteric binding site mutation (V36A in hGLP-1R failed to inhibit compounds 2 and B induced cAMP production, confirming that their binding site distinct from the GLP-1 binding site on GLP-1R. However, K334A mutation of hGLP-1R, which affects Gαs coupling, inhibited GLP-1 as well as compounds 2 and B induced cAMP production, indicating that GLP-1, compounds 2 and B binding induce similar conformational changes in the GLP-1R for Gαs coupling. Additionally, compound 2 or B binding to the hGLP-1R had significantly reduced GLP-1 induced intracellular Ca2+ accumulation, ERK phosphorylation and hGLP-1R internalisation. This study illustrates pharmacology of differential activation of GLP-1R by GLP-1 and compounds 2 and B.

  8. High fat diet and GLP-1 drugs induce pancreatic injury in mice

    Energy Technology Data Exchange (ETDEWEB)

    Rouse, Rodney, E-mail: rodney.rouse@fda.hhs.gov; Xu, Lin; Stewart, Sharron; Zhang, Jun

    2014-04-15

    Glucagon Like Peptide-1 (GLP-1) drugs are currently used to treat type-2 diabetes. Safety concerns for increased risk of pancreatitis and pancreatic ductal metaplasia have accompanied these drugs. High fat diet (HFD) is a type-2 diabetes risk factor that may affect the response to GLP-1 drug treatment. The objective of the present study was to investigate the effects of diet and GLP-1 based drugs on the exocrine pancreas in mice. Experiments were designed in a mouse model of insulin resistance created by feeding a HFD or standard diet (STD) for 6 weeks. The GLP-1 drugs, sitagliptin (SIT) and exenatide (EXE) were administered once daily for additional 6 weeks in both mice fed HFD or STD. The results showed that body weight, blood glucose levels, and serum levels of pro-inflammatory cytokines (TNFα, IL-1β, and KC) were significantly greater in HFD mice than in STD mice regardless of GLP-1 drug treatment. The semi-quantitative grading showed that pancreatic changes were significantly greater in EXE and SIT-treated mice compared to control and that HFD exacerbated spontaneous exocrine pancreatic changes seen in saline-treated mice on a standard diet. Exocrine pancreatic changes identified in this study included acinar cell injury (hypertrophy, autophagy, apoptosis, necrosis, and atrophy), vascular injury, interstitial edema and inflammation, fat necrosis, and duct changes. These findings support HFD as a risk factor to increased susceptibility/severity for acute pancreatitis and indicate that GLP-1 drugs cause pancreatic injury that can be exacerbated in a HFD environment.

  9. High fat diet and GLP-1 drugs induce pancreatic injury in mice

    International Nuclear Information System (INIS)

    Rouse, Rodney; Xu, Lin; Stewart, Sharron; Zhang, Jun

    2014-01-01

    Glucagon Like Peptide-1 (GLP-1) drugs are currently used to treat type-2 diabetes. Safety concerns for increased risk of pancreatitis and pancreatic ductal metaplasia have accompanied these drugs. High fat diet (HFD) is a type-2 diabetes risk factor that may affect the response to GLP-1 drug treatment. The objective of the present study was to investigate the effects of diet and GLP-1 based drugs on the exocrine pancreas in mice. Experiments were designed in a mouse model of insulin resistance created by feeding a HFD or standard diet (STD) for 6 weeks. The GLP-1 drugs, sitagliptin (SIT) and exenatide (EXE) were administered once daily for additional 6 weeks in both mice fed HFD or STD. The results showed that body weight, blood glucose levels, and serum levels of pro-inflammatory cytokines (TNFα, IL-1β, and KC) were significantly greater in HFD mice than in STD mice regardless of GLP-1 drug treatment. The semi-quantitative grading showed that pancreatic changes were significantly greater in EXE and SIT-treated mice compared to control and that HFD exacerbated spontaneous exocrine pancreatic changes seen in saline-treated mice on a standard diet. Exocrine pancreatic changes identified in this study included acinar cell injury (hypertrophy, autophagy, apoptosis, necrosis, and atrophy), vascular injury, interstitial edema and inflammation, fat necrosis, and duct changes. These findings support HFD as a risk factor to increased susceptibility/severity for acute pancreatitis and indicate that GLP-1 drugs cause pancreatic injury that can be exacerbated in a HFD environment

  10. Glucagon-like peptide-1 and its class B G Protein-coupled receptors: A long march to therapeutic successes.

    NARCIS (Netherlands)

    de Graaf, C.; Donnely, D.; Wootten, D.; Lau, J.; Sexton, P.M.; Miller, L.J.; Ahn, J.M.; Liao, J.; Fletcher, M.M.; Yang, D.; Brown, A.J.; Zhou, C.; Deng, J.; Wang, M.W.

    2016-01-01

    Theglucagon-likepeptide (GLP)-1receptor (GLP-1R) is a class B G protein-coupled receptor (GPCR) that mediates the action of GLP-1, a peptide hormone secretedfromthreemajor tissues inhumans,enteroendocrine L cells in the distal intestine, a cells in the pancreas, and the central nervous system, which

  11. Neuroprotective effects of (Val8)GLP-1-Glu-PAL in the MPTP Parkinson's disease mouse model.

    Science.gov (United States)

    Zhang, YanFang; Chen, YiMei; Li, Lin; Hölscher, Christian

    2015-10-15

    Glucagon-like peptide 1 (GLP-1) is a hormone and a growth factor. GLP-1 mimetics are currently on the market as treatments for type 2 diabetes. They also have shown neuroprotective properties in animal models of neurodegenerative disorders. In addition, the GLP-1 mimetic exendin-4 has shown protective effects in animal models of Parkinson's disease (PD), and a first clinical trial in PD patients showed promising results. (Val8)GLP-1-glu-PAL is a new GLP-1 analogue which has a longer biological half-life than exendin-4. We previously showed that (Val8)GLP-1-glu-PAL has neuroprotective properties. Here we tested the drug in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. MPTP was injected (30mg/kg i.p.) along with (Val8)GLP-1-glu-PAL (25nmol/kg i.p.) once-daily for 8 days. (Val8)GLP-1-glu-PAL showed good effects in preventing the MPTP-induced motor impairment (Rotarod, open field locomotion, swim test), reduction in tyrosine hydroxylase levels (dopamine synthesis) in the substantia nigra, a reduction of activated caspase 3 levels, of TUNEL positive cell numbers, of the pro-apoptotic signaling molecule BAX and an increase in the growth signaling molecule Bcl-2. The results demonstrate that (Val8)GLP-1-glu-PAL shows promise as a novel treatment of PD. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Gastric bypass surgery: Improving psoriasis through a GLP-1-dependent mechanism?

    DEFF Research Database (Denmark)

    Faurschou, Annesofie; Zachariae, Claus; Skov, Lone

    2011-01-01

    surgery. This most likely contributes importantly to the acute remission of type 2 diabetes, which is often induced by gastric bypass operations. The hormone is not hypersecreted after the purely restrictive bariatric procedure gastric banding and no case reports exist on improvement in psoriasis...... following gastric banding. Intriguingly, recent studies describe that GLP-1 may convey anti-inflammatory effects in addition to its effects on glucose homeostasis. Also, GLP-1 reduces appetite and gastrointestinal motility including gastric emptying, which reduces food intake and leads to weight loss. Thus...

  13. GLP-1 signals via ERK in peripheral nerve and prevents nerve dysfunction in diabetic mice

    DEFF Research Database (Denmark)

    Jolivalt, CG; Fineman, M; Deacon, Carolyn F.

    2011-01-01

    not affect blood sugar, insulin levels or paw thermal response latencies in either control or diabetic mice. However, the reductions of motor nerve conduction velocity and paw intraepidermal fibre density seen in diabetic mice were attenuated by exenatide treatment. Conclusions: These data show...... that the peripheral nerve of diabetic rodents exhibits functional GLP-1R and suggest that GLP-1R-mediated ERK-signalling in sciatic nerve of diabetic rodents may protect large motor fibre function and small C fibre structure by a mechanism independent of glycaemic control....

  14. Exaggerated secretion of glucagon-like peptide-1 (GLP-1) could cause reactive hypoglycaemia

    DEFF Research Database (Denmark)

    Toft-Nielsen, M; Madsbad, Sten; Holst, Jens Juul

    1998-01-01

    The plasma concentrations of the insulinotropic incretin hormone, glucagon-like peptide-1 (GLP-1) are abnormally high after oral glucose in partially gastrectomised subjects with reactive hypoglycaemia, suggesting a causal relationship. Because of the glucose-dependency of its effects, it is impo......The plasma concentrations of the insulinotropic incretin hormone, glucagon-like peptide-1 (GLP-1) are abnormally high after oral glucose in partially gastrectomised subjects with reactive hypoglycaemia, suggesting a causal relationship. Because of the glucose-dependency of its effects...

  15. Microbial regulation of GLP-1 and L-cell biology

    DEFF Research Database (Denmark)

    Greiner, Thomas U; Bäckhed, Gert Fredrik

    2016-01-01

    BACKGROUND: The gut microbiota is associated with several of metabolic diseases, including obesity and type 2 diabetes and affects host physiology through distinct mechanisms. The microbiota produces a vast array of metabolites that signal to host cells in the intestine as well as in more distal...... organs. SCOPE OF REVIEW: Enteroendocrine cells acts as 'chemo sensors' of the intestinal milieu by expressing a large number of receptors, which respond to different metabolites and nutrients, and signal to host by a wide variety of hormones. However, enteroendocrine cells differ along the length...... of the gut in terms of hormones expressed and receptor repertoire. Also, the microbial ecology and dietary substrates differ along the length of the gut, providing further evidence for unique functions of specific subpopulations among enteroendocrine cells. Here we will review how the gut microbiota...

  16. Diabetes and obesity treatment based on dual incretin receptor activation

    DEFF Research Database (Denmark)

    Skow, M A; Bergmann, N C; Knop, F K

    2016-01-01

    , whereas GIP seems to affect lipid metabolism. The introduction of selective GLP-1 receptor (GLP-1R) agonists for the treatment of type 2 diabetes and obesity has increased the scientific and clinical interest in incretins. Combining the body weight-lowering and glucose-lowering effects of GLP-1...... with a more potent improvement of β cell function through additional GIP action could potentially offer a more effective treatment of diabetes and obesity, with fewer adverse effects than selective GLP-1R agonists; therefore, new drugs designed to co-activate both the GIP receptor (GIPR) and the GLP-1R...

  17. The 2-monoacylglycerol moiety of dietary fat appears to be responsible for the fat-induced release of GLP-1 in humans.

    Science.gov (United States)

    Mandøe, Mette J; Hansen, Katrine B; Hartmann, Bolette; Rehfeld, Jens F; Holst, Jens J; Hansen, Harald S

    2015-09-01

    Dietary triglycerides can, after digestion, stimulate the intestinal release of incretin hormones through activation of G protein-coupled receptor (GPR) 119 by 2-monoacylglycerol and by the activation of fatty acid receptors for long- and short-chain fatty acids. Medium-chain fatty acids do not stimulate the release of intestinal hormones. To dissect the mechanism of fat-induced glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) release in humans, we compared the effects of tributyrin (containing short-chain fatty acids; i.e., butyric acid), olive oil [containing long-chain fatty acids; e.g., oleic acid plus 2-oleoyl glycerol (2-OG)], and 1,3-dioctanoyl-2-oleoyl glycerol (C8-dietary oil), which is digested to form medium-chain fatty acids : i.e., octanoic acid : and 2-OG. In a randomized, single-blinded crossover study, 12 healthy white men [mean age: 24 y; BMI (in kg/m(2)): 22] were given the following 4 meals on 4 different days: 200 g carrots + 6.53 g tributyrin, 200 g carrots + 13.15 g C8-dietary oil, 200 g carrots + 19 g olive oil, or 200 g carrots. All of the lipids totaled 0.0216 mol. Main outcome measures were incremental areas under the curve for total GLP-1, GIP, and cholecystokinin (CCK) in plasma. C8-dietary oil and olive oil showed the same GLP-1 response [583 ± 101 and 538 ± 71 (pmol/L) × 120 min; P = 0.733], whereas the GIP response was higher for olive oil than for C8-dietary oil [3293 ± 404 and 1674 ± 270 (pmol/L) × 120 min; P = 0.002]. Tributyrin and carrots alone resulted in no increase in any of the measured hormones. Peptide YY (PYY) and neurotensin responses resembled those of GLP-1. Only olive oil stimulated CCK release. Under our study conditions, 2-OG and GPR119 activation can fully explain the olive oil-induced secretion of GLP-1, PYY, and neurotensin. In contrast, both oleic acid and 2-OG contributed to the GIP response. Dietary butyrate did not stimulate gut hormone secretion. Olive oil

  18. Radio-immunoassays for glucagon-like peptides 1 and 2 (GLP-1 and GLP-2)

    DEFF Research Database (Denmark)

    Orskov, C; Holst, J J

    1987-01-01

    Gene-sequencing studies have shown that the glucagon precursor contains two additional glucagon-like sequences, the so-called glucagon-like peptides 1 and 2 (GLP-1 and GLP-2). We developed radio-immunoassays against synthetic peptides corresponding to these sequences. Antisera were raised in rabb...

  19. 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...

  20. Minor Contribution of Endogenous GLP-1 and GLP-2 to Postprandial Lipemia in Obese Men

    DEFF Research Database (Denmark)

    Matikainen, Niina; Björnson, Elias; Söderlund, Sanni

    2016-01-01

    CONTEXT: Glucose and lipids stimulate the gut-hormones glucagon-like peptide (GLP)-1, GLP-2 and glucose-dependent insulinotropic polypeptide (GIP) but the effect of these on human postprandial lipid metabolism is not fully clarified. OBJECTIVE: To explore the responses of GLP-1, GLP-2 and GIP after...... and after a fat-rich meal in 65 healthy obese (BMI 26.5-40.2 kg/m2) male subjects. Triglycerides (TG), apoB48 and apoB100 in TG-rich lipoproteins (chylomicrons, VLDL1 and VLDL2) were measured after the fat-rich meal. MAIN OUTCOME MEASURES: Postprandial responses (area under the curve, AUC) for glucose...... AUCs were lower, but the AUCs for GLP-1, GLP-2 and GIP were significantly higher after the fat-rich meal than after the OGTT. The peak value for all hormones appeared at 120 minutes after the fat-rich meal, compared to 30 minutes after the OGTT. After the fat-rich meal, the AUCs for GLP-1, GLP-2...

  1. Dose response of subcutaneous GLP-1 infusion in patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Torekov, Signe Sørensen; Kipnes, M S; Harley, R E

    2011-01-01

    To evaluate the dose-response relationship of the recombinant glucagon-like peptide-1 (7-36) amide (rGLP-1) administered by continuous subcutaneous infusion (CSCI) in subjects with type 2 diabetes, with respect to reductions in fasting, postprandial and 11-h serum glucose profiles....

  2. Presence and dynamics of leptin, GLP-1, and PYY in human breast milk at early postpartum.

    Science.gov (United States)

    Schueler, Jessica; Alexander, Brenda; Hart, Ann Marie; Austin, Kathleen; Larson-Meyer, D Enette

    2013-07-01

    The presence of appetite hormones, namely glucagon-like peptide-1 (GLP-1), peptide YY (PYY), and leptin in breast milk may be important in infant feeding regulation and infant growth. This study evaluated whether concentrations of GLP-1, PYY, and leptin change across a single feeding (from fore- to hindmilk), and are associated with maternal and infant anthropometrics. Thirteen postpartum women (mean ± SD: 25.6 ± 4.5 years, 72.0 ± 11.9 kg) provided fore- and hindmilk samples 4-5 weeks after delivery and underwent measurements of body weight and composition by Dual X-ray Absorptiometry. GLP-1, PYY, and leptin concentrations were measured using radioimmunoassay, and milk fat content was determined by creamatocrit. Concentration of GLP-1 and content of milk fat was higher in hindmilk than foremilk (P ≤ 0.05). PYY and leptin concentrations did not change between fore- and hindmilk. Both leptin concentration and milk fat content were correlated with indices of maternal adiposity, including body mass index (r = 0.65-0.85, P milk may be important in infant appetite and growth regulation. Copyright © 2013 The Obesity Society.

  3. Reduced postprandial GLP-1 responses in women with gestational diabetes mellitus

    DEFF Research Database (Denmark)

    Bonde, L; Vilsbøll, T; Nielsen, T

    2013-01-01

    AIM: We investigated postprandial glucagon-like peptide-1 (GLP-1) responses in pregnant women with and without gestational diabetes mellitus (GDM) and again following delivery when normal glucose tolerance (NGT) was re-established. METHODS: Eleven women with GDM [plasma glucose (PG) concentration...

  4. Acute activation of GLP-1-expressing neurons promotes glucose homeostasis and insulin sensitivity

    Science.gov (United States)

    Glucagon-like peptides are co-released from enteroendocrine L cells in the gut and preproglucagon (PPG) neurons in the Brainstem. PPG-derived GLP-1/2 are probably key neuroendocrine signals for the control of energy balance and glucose Homeostasis. The objective of this study was to determine whethe...

  5. Differential incretin effects of GIP and GLP-1 on gastric emptying, appetite, and insulin-glucose homeostasis

    DEFF Research Database (Denmark)

    Edholm, T; Degerblad, M; Grybäck, P

    2010-01-01

    Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are major incretins with important effects on glucoregulatory functions. The aim of this study was to investigate effects of GIP and GLP-1 on gastric emptying and appetite after a mixed meal, and effects...

  6. Effect of oral contraceptives and/or metformin on GLP-1 secretion and reactive hypoglycaemia in polycystic ovary syndrome

    DEFF Research Database (Denmark)

    Glintborg, Dorte; Mumm, Hanne; Holst, Jens Juul

    2017-01-01

    CONTEXT: Insulin resistance in polycystic ovary syndrome (PCOS) may increase the risk of reactive hypoglycaemia (RH) and decrease glucagon-like peptide-1 (GLP-1) secretion. The possible effects of treatment with oral contraceptives (OCP) and/or metformin on GLP-1 secretion and risk of RH in PCOS...

  7. GLP-1 and GLP-2 act in concert to inhibit fasted, but not fed, small bowel motility in the rat

    DEFF Research Database (Denmark)

    Bozkurt, Ayhan; Näslund, Erik; Holst, Jens Juul

    2002-01-01

    Small bowel motility was studied in rats at increasing (1-20 pmol/kg/min) intravenous doses of either glucagon-like peptide-1 (GLP-1) or glucagon-like peptide-2 (GLP-2) alone, or in combination in the fasted and fed state. There was a dose-dependent inhibitory action of GLP-1 on the migrating myo...... demonstrates an additive effect of peripheral administration of GLP-1 and GLP-2 on fasted small bowel motility. In the fed state, GLP-1 and GLP-2 seem to display counter-balancing effects on motility of the small intestine....... myoelectric complex (MMC), where the dose of 5 pmol/kg/min induced an increased MMC cycle length. No effect was seen with GLP-2 alone, but the combination of GLP-1 and GLP-2 induced a more pronounced inhibitory effect, with significant increase of the MMC cycle length from a dose of 2 pmol/kg/min. During fed...

  8. Effect of oral contraceptives and/or metformin on GLP-1 secretion and reactive hypoglycaemia in polycystic ovary syndrome

    Directory of Open Access Journals (Sweden)

    Dorte Glintborg

    2017-06-01

    Full Text Available Context: Insulin resistance in polycystic ovary syndrome (PCOS may increase the risk of reactive hypoglycaemia (RH and decrease glucagon-like peptide-1 (GLP-1 secretion. The possible effects of treatment with oral contraceptives (OCP and/or metformin on GLP-1 secretion and risk of RH in PCOS is undetermined. Setting: Outpatient clinic. Patients and interventions: Randomized, controlled clinical trial. Ninety women with PCOS were randomized to 12-month treatment with OCP (150 mg desogestrel + 30 mg ethinylestradiol, metformin (2 g/day or metformin + OCP. Five-hour oral glucose tolerance tests (5-h OGTT measuring fasting and area under the curve (AUC for GLP-1, glucose, insulin and C-peptide were performed before and after the intervention period. Sixty-five women completed the study and 34 weight-matched healthy women were included as controls. Main outcome measures: Changes in GLP-1, glucose, insulin and C-peptide during 5-h OGTT. Results: Fasting GLP-1 levels increased during metformin + OCP vs OCP treatment, whereas AUC GLP-1 levels were unchanged during medical treatment. The prevalence of reactive hypoglycemia increased from 9/65 to 14/65 after intervention (P < 0.01 and was more common after treatment with metformin + OCP (increase from 3/23 to 6/23, P = 0.01. Reactive hypoglycaemia was associated with higher insulin and C-peptide levels during 5-h OGTT, but was unassociated with BMI and AUC GLP-1. GLP-1 levels were comparable in PCOS vs controls. AUC GLP-1 levels were significantly lower in obese vs lean patients and were inversely associated with BMI. Conclusions: AUC GLP-1 levels were unchanged during treatment. Increased risk of hypoglycemia during metformin + OCP could be associated with increased insulin secretion.

  9. The glucagon-like peptide-1 metabolite GLP-1-(9-36) amide reduces postprandial glycemia independently of gastric emptying and insulin secretion in humans

    DEFF Research Database (Denmark)

    Meier, Juris J; Gethmann, Arnica; Nauck, Michael A

    2006-01-01

    Glucagon-like peptide 1 (GLP-1) lowers glycemia by modulating gastric emptying and endocrine pancreatic secretion. Rapidly after its secretion, GLP-1-(7-36) amide is degraded to the metabolite GLP-1-(9-36) amide. The effects of GLP-1-(9-36) amide in humans are less well characterized. Fourteen...... healthy volunteers were studied with intravenous infusion of GLP-1-(7-36) amide, GLP-1-(9-36) amide, or placebo over 390 min. After 30 min, a solid test meal was served, and gastric emptying was assessed. Blood was drawn for GLP-1 (total and intact), glucose, insulin, C-peptide, and glucagon measurements....... Administration of GLP-1-(7-36) amide and GLP-1-(9-36) amide significantly raised total GLP-1 plasma levels. Plasma concentrations of intact GLP-1 increased to 21 +/- 5 pmol/l during the infusion of GLP-1-(7-36) amide but remained unchanged during GLP-1-(9-36) amide infusion [5 +/- 3 pmol/l; P

  10. Feedback suppression of meal-induced glucagon-like peptide-1 (GLP-1) secretion mediated through elevations in intact GLP-1 caused by dipeptidyl peptidase-4 inhibition

    DEFF Research Database (Denmark)

    Baranov, Oleg; Kahle, Melanie; Deacon, Carolyn F

    2016-01-01

    AIM: To compare directly the clinical effects of vildagliptin and sitagliptin in patients with type 2 diabetes, with a special emphasis on incretin hormones and L-cell feedback inhibition induced by dipeptidyl peptidase (DPP-4) inhibition. METHODS: A total of 24 patients (12 on a diet/exercise re......AIM: To compare directly the clinical effects of vildagliptin and sitagliptin in patients with type 2 diabetes, with a special emphasis on incretin hormones and L-cell feedback inhibition induced by dipeptidyl peptidase (DPP-4) inhibition. METHODS: A total of 24 patients (12 on a diet....../exercise regimen, 12 on metformin) were treated, in randomized order, for 7-9 days, with either vildagliptin (50 mg twice daily = 100 mg/d), sitagliptin (100 mg once daily in those on diet, 50 mg twice daily in those on metformin treatment = 100 mg/d) or placebo (twice daily). A mixed-meal test was performed....... RESULTS: Intact glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide concentrations were doubled by both DPP-4 inhibitors. Meal-related total GLP-1 responses were reduced by vildagliptin and sitagliptin treatment alike in the majority of patients (vildagliptin: p = 0...

  11. Selective beneficial cardiometabolic effects of vertical sleeve gastrectomy are predominantly mediated through glucagon-like peptide (GLP-1 in Zucker diabetic fatty rats

    Directory of Open Access Journals (Sweden)

    Sunil Kumar

    2016-12-01

    Conclusion: Enhanced GLP-1 secretion post VSG imparted beneficial cardiometabolic effects on blood glucose, insulin, total cholesterol, triglyceride, bile acids and L-PGDS levels which were abated in the presence of GLP-1 antagonist.

  12. Comparison Review of Short-Acting and Long-Acting Glucagon-like Peptide-1 Receptor Agonists

    OpenAIRE

    Uccellatore, Annachiara; Genovese, Stefano; Dicembrini, Ilaria; Mannucci, Edoardo; Ceriello, Antonio

    2015-01-01

    Glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1 RAs) are useful tools for treating type 2 diabetes mellitus. In their recent position statement, the American Diabetes Association and European Association for the Study of Diabetes recommend GLP1-RAs as add-on to metformin when therapeutic goals are not achieved with monotherapy, particularly for patients who wish to avoid weight gain or hypoglycemia. GLP1-RAs differ substantially in their duration of action, frequency of administratio...

  13. Effect of oral contraceptives and/or metformin on GLP-1 secretion and reactive hypoglycemia in PCOS

    DEFF Research Database (Denmark)

    Glintborg, Dorte; Mumm, Hanne; Holst, Jens Juul

    2017-01-01

    CONTEXT: Insulin resistance in polycystic ovary syndrome (PCOS) may increase the risk of reactive hypoglycaemia (RH) and decrease glucagon-like peptide-1 (GLP-1) secretion. The possible effects of treatment with oral contraceptives (OCP) and/or metformin on GLP-1 secretion and risk of RH in PCOS ...... significantly lower in obese vs. lean patients and were inversely associated with BMI. CONCLUSIONS: AUC GLP-1 levels were unchanged during treatment. Increased risk of hypoglycemia during metformin +OCP could be associated with increased insulin secretion.......CONTEXT: Insulin resistance in polycystic ovary syndrome (PCOS) may increase the risk of reactive hypoglycaemia (RH) and decrease glucagon-like peptide-1 (GLP-1) secretion. The possible effects of treatment with oral contraceptives (OCP) and/or metformin on GLP-1 secretion and risk of RH in PCOS......, glucose, insulin, and C-peptide during 5 h OGTT. RESULTS: Fasting GLP-1 levels increased during metformin+OCP vs. OCP treatment, whereas AUC GLP-1 levels were unchanged during medical treatment. The prevalence of reactive hypoglycemia increased from 9/65 to 14/65 after intervention (P

  14. Gastric bypass surgery: Improving psoriasis through a GLP-1-dependent mechanism?

    DEFF Research Database (Denmark)

    Faurschou, Annesofie; Zachariae, Claus; Skov, Lone

    2011-01-01

    surgery. This most likely contributes importantly to the acute remission of type 2 diabetes, which is often induced by gastric bypass operations. The hormone is not hypersecreted after the purely restrictive bariatric procedure gastric banding and no case reports exist on improvement in psoriasis......, both a direct anti-inflammatory effect of GLP-1 as well as an indirect effect through weight loss could contribute to improvement in psoriasis. A potential involvement of GLP-1 in the remission of psoriasis observed after bariatric surgery offers exciting possibilities for research and eventually...... bypass surgery in patients with psoriasis may result in complete remission of the disease. A substantial weight loss is achieved in the months following surgery, which is likely to reduce psoriasis symptoms and risk of comorbidities. Interestingly, however, it has been described that improvement...

  15. 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

  16. South Asian Consensus Guideline: Use of GLP-1 analogue therapy in diabetes during Ramadan

    Directory of Open Access Journals (Sweden)

    Md Faruque Pathan

    2012-01-01

    Full Text Available Ramadan is a lunar based month, during which Muslims across the world observe the ritual fast. This provides a challenge not only to the diabetic patient who wishes to observe the fast but also to the health care professional managing his diabetes. The challenge is to use therapies which are effective in maintaining good glycemic control and at the same time have a low propensity to cause hypoglycemia during the several hours of no calorie intake. The GLP-1 analogues are unique agents which are effective in providing glycemic reduction with a very low risk of hypoglycemia and hence find an important place in the management of diabetes during Ramadan. This Consensus Statement describes the pre-Ramadan assessment, planning, prescription and management and monitoring of patients who are on GLP-1 analogues, with or without other antidiabetic therapies.

  17. Characterization of GLP-1 effects on beta-cell function after meal ingestion in humans

    DEFF Research Database (Denmark)

    Ahrén, Bo; Holst, Jens Juul; Mari, Andrea

    2003-01-01

    OBJECTIVE: Glucagon-like peptide 1 (GLP-1) is an incretin that augments insulin secretion after meal intake and is developed for treatment of type 2 diabetes. As a novel therapeutic agent, characteristics of its beta-cell effects are important to establish. Previously, beta-cell effects of GLP-1...... have been characterized in humans during graded intravenous infusions of glucose, whereas its effects after more physiological stimuli, like meal intake, are not known. RESEARCH DESIGN AND METHODS: Eight women (aged 69 years, fasting glucose 3.7-10.3 mmol/l, BMI 22.4-43.9 kg/m(2)) who had fasted...... meal augments insulin secretion in humans by a dose...

  18. Implementation of GLP-1 based therapy of type 2 diabetes mellitus using DPP-IV inhibitors

    DEFF Research Database (Denmark)

    Holst, Jens Juul

    2003-01-01

    GLP-1 is a peptide hormone from the intestinal mucosa. It is secreted in response to meal ingestion and normally functions in the so-called ileal brake i. e. inhibition of upper gastrointestinal motility and secretion when nutrients are present in the distal small intestine. It also induces satiety...... of the peptide is necessary because of an exceptionally rapid rate of degradation catalyzed the enzyme dipeptidyl peptidase IV. With inhibitors of this enzyme, it is possible to protect the endogenous hormone and thereby elevate both fasting and postprandial levels of the active hormone. This leads to enhanced...... insulin secretion and glucose turnover. But will DPP-IV inhibition enhance all effects of the endogenous peptide? The mode of action of GLP-1 is complex involving also interactions with sensory neurons and the central nervous system, where a DPP-IV mediated degradation does not seem to occur. Therefore...

  19. 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...

  20. Specific inhibition of bile acid transport alters plasma lipids and GLP-1

    DEFF Research Database (Denmark)

    Rudling, Mats; Camilleri, Michael; Graffner, Hans

    2015-01-01

    mellitus. The objectives of this study were to evaluate metabolic effects of elobixibat. Effects on plasma lipids and BA synthesis were evaluated utilizing a 4-week, placebo-controlled study in patients with dyslipidemia while changes of glucagon-like peptide-1 (GLP-1) by elobixibat was assayed in samples......: In the dyslipidemia study LDL cholesterol was reduced by 7.4 % (p = 0.044), and the LDL/HDL ratio was decreased by 18 % (p = 0.004). Serum C4 increased, indicating that BA synthesis was induced. No serious adverse events were recorded. In the CC study, GLP-1 increased significantly in both the 15 mg (20.7 ± 2.4 pmol...

  1. GLP-1/glucagon coagonism restores leptin responsiveness in obese mice chronically maintained on an obesogenic diet

    DEFF Research Database (Denmark)

    Clemmensen, Christoffer; Chabenne, Joseph; Finan, Brian

    2014-01-01

    We recently reported restoration of leptin responsiveness in diet-induced obese (DIO) mice using a pharmacologically optimized, polyethylene-glycolated (PEG)-leptin analog in combination with exendin-4 or FGF21. However, the return of leptin action required discontinuation of high-fat diet (HFD...... cotreatment. In summary, we report that GLP-1/glucagon coagonism restores leptin responsiveness in mice maintained on a HFD, thus emphasizing the translational value of this polypharmacotherapy for the treatment of obesity and diabetes....

  2. Acute activation of GLP-1-expressing neurons promotes glucose homeostasis and insulin sensitivity

    OpenAIRE

    Xuemei Shi; Shaji Chacko; Feng Li; Depei Li; Douglas Burrin; Lawrence Chan; Xinfu Guan

    2017-01-01

    Objective: Glucagon-like peptides are co-released from enteroendocrine L cells in the gut and preproglucagon (PPG) neurons in the brainstem. PPG-derived GLP-1/2 are probably key neuroendocrine signals for the control of energy balance and glucose homeostasis. The objective of this study was to determine whether activation of PPG neurons per se modulates glucose homeostasis and insulin sensitivity in vivo. Methods: We generated glucagon (Gcg) promoter-driven Cre transgenic mice and injected...

  3. Preserved inhibitory potency of GLP-1 on glucagon secretion in type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Hare, Kristine J; Knop, Filip K; Asmar, Meena

    2009-01-01

    OBJECTIVE: Glucagon-like peptide-1 (GLP-1) is insulinotropic, but its effect on the alpha-cell is less clear. We investigated the dose-response relationship for GLP-1-induced glucagon suppression in patients with type 2 diabetes (T2DM) and healthy controls. DESIGN: Ten patients with T2DM (duration...... to d 2 (1733 +/- 193 3h x pmol/liter; P 2DM. A similar reduction in AUC for glucagon was observed in healthy controls [1122 +/- 186 (d 1) vs. 1733 +/- 312 3h x pmol/liter (d 2); P diabetic alpha-cell appears to be highly sensitive to the inhibitory...... of DM, 4 +/- 1 yr; glycosylated hemoglobin, 7.1 +/- 0.3%) were studied on 2 d, with stepwise increasing GLP-1 infusions (0.25, 0.5, 1.0, and 2.0 pmol x kg(-1) x min(-1)) (d 1) or saline (d 2) with plasma glucose (PG) clamped at fasting level. On d 3, patient PG was normalized overnight using a variable...

  4. Appetite-related peptides in childhood and adolescence: role of ghrelin, PYY, and GLP-1.

    Science.gov (United States)

    Horner, Katy; Lee, SoJung

    2015-11-01

    During childhood and adolescence, a number of factors, including age, puberty, sex, race, and body composition, may contribute to differences in satiety, food intake, and appetite-related peptides. These peptides include the orexigenic peptide ghrelin and anorexigenic gut peptides peptide YY (PYY) and glucagon-like peptide-1 (GLP-1). For example, lower fasting ghrelin levels, lower postprandial ghrelin suppression, and blunted PYY and GLP-1 responses to food intake could contribute to a dysregulation of appetite in already obese children and adolescents. Whereas, changes in these peptides observed during puberty could facilitate growth. A greater understanding of the major moderating factors of appetite-related peptides in the pediatric population is essential to improve interpretation of study findings and for effective tailoring of strategies targeting appetite control to individuals. While more studies are needed, there is some evidence to suggest that exercise-based lifestyle interventions could be a potential therapeutic strategy to improve appetite-peptide profiles in overweight and obese children and adolescents. The aim of this review is (i) to discuss the potential moderating factors of ghrelin, PYY, and GLP-1, including age and puberty, sex, race and body composition; and (ii) to examine the effects of exercise interventions on these appetite-related gut peptides in children and adolescents.

  5. Upregulation of alpha cell glucagon-like peptide 1 (GLP-1) in Psammomys obesus--an adaptive response to hyperglycaemia?

    DEFF Research Database (Denmark)

    Hansen, A M K; Bödvarsdottir, T B; Nordestgaard, D N E

    2011-01-01

    of the study was to evaluate if, during the development of diabetes, alpha cells produce GLP-1 that, in turn, might trigger beta cell growth. Methods Beta cell mass, GLP-1 and insulin levels were measured in the gerbil Psammomys obesus (P. obesus), a rodent model of nutritionally induced diabetes. Furthermore...... from alpha cells is upregulated in P. obesus during the development of diabetes. A similar response is seen in islets exposed to high glucose, which supports the hypothesis that GLP-1 released from alpha cells promotes an increase in beta cell mass and function during metabolic challenge...

  6. Glucagon-like peptides GLP-1 and GLP-2, predicted products of the glucagon gene, are secreted separately from pig small intestine but not pancreas

    DEFF Research Database (Denmark)

    Holst, J J; Poulsen, Steen Seier

    1986-01-01

    We developed specific antibodies and RIAs for glucagon-like peptides 1 and 2 (GLP-1 and GLP-2), two predicted products of the glucagon gene, and studied the occurrence, nature, and secretion of immunoreactive GLP-1 and GLP-2 in pig pancreas and small intestine. Immunoreactive GLP-1 and GLP-2 were...

  7. Dulaglutide, a long-acting GLP-1 analog fused with an Fc antibody fragment for the potential treatment of type 2 diabetes

    DEFF Research Database (Denmark)

    Jimenez-Solem, Espen; Rasmussen, Mette H; Christensen, Mikkel

    2010-01-01

    Dulaglutide (LY-2189265) is a novel, long-acting glucagon-like peptide 1 (GLP-1) analog being developed by Eli Lilly for the treatment of type 2 diabetes mellitus (T2DM). Dulaglutide consists of GLP-1(7-37) covalently linked to an Fc fragment of human IgG4, thereby protecting the GLP-1 moiety from...

  8. Glucagon-like peptide 1 receptor activation regulates cocaine actions and dopamine homeostasis in the lateral septum by decreasing arachidonic acid levels

    DEFF Research Database (Denmark)

    Reddy, I A; Pino, J A; Weikop, P

    2016-01-01

    Agonism of the glucagon-like peptide 1 (GLP-1) receptor (GLP-1R) has been effective at treating aspects of addictive behavior for a number of abused substances, including cocaine. However, the molecular mechanisms and brain circuits underlying the therapeutic effects of GLP-1R signaling on cocain...

  9. Absence of a memory effect for the insulinotropic action of glucagon-like peptide 1 (GLP-1) in healthy volunteers

    DEFF Research Database (Denmark)

    Meier, S; Hücking, K; Ritzel, R

    2003-01-01

    of glucose was injected intravenously (0.33 g/kg body weight). GLP-1 was infused from (b). - 60 to 120 min, (c). - 210 to - 30 min, or (d). - 300 to - 120 min. Glucose (glucose oxidase), insulin, C-peptide, GLP-1, and glucagon (immunoassays) were determined. Statistical analysis was carried out by ANOVA......BACKGROUND/AIMS: The term memory effect refers to the phenomenon that B cell stimuli retain some of their insulinotropic effects after they have been removed. Memory effects exist for glucose and sulfonylureas. It is not known whether there is a B-cell memory for incretin hormones such as GLP-1...... and appropriate post hoc tests. RESULTS: GLP-1 plasma levels during the infusion periods were elevated to 89 +/- 9, 85 +/- 13, and 89 +/- 6 pmol/l (p Glucose was eliminated faster (p

  10. Effects of subcutaneous glucagon-like peptide 1 (GLP-1 [7-36 amide]) in patients with NIDDM

    DEFF Research Database (Denmark)

    Nauck, M A; Wollschläger, D; Werner, J

    1996-01-01

    with the indicator-dilution method and phenol red. Repeated measures ANOVA was used for statistical analysis. GLP-1 injection led to a short-lived increment in GLP-1 concentrations (peak at 30-60 min, then return to basal levels after 90-120 min). Each GLP-1 injection stimulated insulin (insulin, C-peptide, p ....0001, respectively) and inhibited glucagon secretion (p ... emptying for 30-45 min (p statistically different from placebo) followed by emptying at a normal rate. As a consequence, integrated incremental glucose responses were reduced by 40% (p = 0.051). In conclusion, subcutaneous GLP-1 [7-36 amide] has similar effects in NIDDM patients as an intravenous...

  11. Crystal structure of the ligand-bound glucagon-like peptide-1 receptor extracellular domain.

    Science.gov (United States)

    Runge, Steffen; Thøgersen, Henning; Madsen, Kjeld; Lau, Jesper; Rudolph, Rainer

    2008-04-25

    The glucagon-like peptide-1 receptor (GLP-1R) belongs to Family B1 of the seven-transmembrane G protein-coupled receptors, and its natural agonist ligand is the peptide hormone glucagon-like peptide-1 (GLP-1). GLP-1 is involved in glucose homeostasis, and activation of GLP-1R in the plasma membrane of pancreatic beta-cells potentiates glucose-dependent insulin secretion. The N-terminal extracellular domain (nGLP-1R) is an important ligand binding domain that binds GLP-1 and the homologous peptide Exendin-4 with differential affinity. Exendin-4 has a C-terminal extension of nine amino acid residues known as the "Trp cage", which is absent in GLP-1. The Trp cage was believed to interact with nGLP-1R and thereby explain the superior affinity of Exendin-4. However, the molecular details that govern ligand binding and specificity of nGLP-1R remain undefined. Here we report the crystal structure of human nGLP-1R in complex with the antagonist Exendin-4(9-39) solved by the multiwavelength anomalous dispersion method to 2.2A resolution. The structure reveals that Exendin-4(9-39) is an amphipathic alpha-helix forming both hydrophobic and hydrophilic interactions with nGLP-1R. The Trp cage of Exendin-4 is not involved in binding to nGLP-1R. The hydrophobic binding site of nGLP-1R is defined by discontinuous segments including primarily a well defined alpha-helix in the N terminus of nGLP-1R and a loop between two antiparallel beta-strands. The structure provides for the first time detailed molecular insight into ligand binding of the human GLP-1 receptor, an established target for treatment of type 2 diabetes.

  12. No effect of beta-adrenergic blockade on hypoglycaemic effect of glucagon-like peptide-1 (GLP-1) in normal subjects

    DEFF Research Database (Denmark)

    Toft-Nielsen, M; Hvidberg, A; Hilsted, Jannik

    1996-01-01

    GLP-1 administration decreases blood glucose levels in normal subjects and non-insulin-dependent diabetes mellitus patients and is therefore proposed as a treatment for diabetic hyperglycaemia. The glucose lowering effect of GLP-1 is glucose dependent and therefore self-limiting, but it is not kn...... on the two GLP-1 infusion days; and (5) an increase in catecholamine levels in the GLP-1/saline experiment and also in the beta-blockade experiments. We conclude that adrenergic counterregulation plays an insignificant role in curtailing GLP-1's glucose lowering effect....

  13. Glucagon-like peptide-1 (GLP-1) raises blood-brain glucose transfer capacity and hexokinase activity in human brain

    OpenAIRE

    Gejl, Michael; Lerche, Susanne; Egefjord, L?rke; Brock, Birgitte; M?ller, Niels; Vang, Kim; Rodell, Anders B.; Bibby, Bo M.; Holst, Jens J.; Rungby, J?rgen; Gjedde, Albert

    2013-01-01

    In hyperglycemia, glucagon-like peptide-1 (GLP-1) lowers brain glucose concentration together with increased net blood-brain clearance and brain metabolism, but it is not known whether this effect depends on the prevailing plasma glucose (PG) concentration. In hypoglycemia, glucose depletion potentially impairs brain function. Here, we test the hypothesis that GLP-1 exacerbates the effect of hypoglycemia. To test the hypothesis, we determined glucose transport and consumption rates in seven h...

  14. Small Molecule Drug Discovery at the Glucagon-Like Peptide-1 Receptor

    Directory of Open Access Journals (Sweden)

    Francis S. Willard

    2012-01-01

    Full Text Available The therapeutic success of peptide glucagon-like peptide-1 (GLP-1 receptor agonists for the treatment of type 2 diabetes mellitus has inspired discovery efforts aimed at developing orally available small molecule GLP-1 receptor agonists. Although the GLP-1 receptor is a member of the structurally complex class B1 family of GPCRs, in recent years, a diverse array of orthosteric and allosteric nonpeptide ligands has been reported. These compounds include antagonists, agonists, and positive allosteric modulators with intrinsic efficacy. In this paper, a comprehensive review of currently disclosed small molecule GLP-1 receptor ligands is presented. In addition, examples of “ligand bias” and “probe dependency” for the GLP-1 receptor are discussed; these emerging concepts may influence further optimization of known molecules or persuade designs of expanded screening strategies to identify novel chemical starting points for GLP-1 receptor drug discovery.

  15. Serum levels of glucagon-like peptide (GLP-1 and GLP-2 in patients with Hashimoto′s thyroiditis

    Directory of Open Access Journals (Sweden)

    Yue Jin

    2015-01-01

    Full Text Available Background: The influence of Hashimoto′s thyroiditis (HT with subclinical hypothyroidism or euthyroid status on the alteration of glucagon-like peptide (GLP-1 and GLP-2 levels remains uncertain. Materials and Methods: Twenty-four untreated HT patients with subclinical hypothyroidism, 24 euthyroid HT patients, and 24 age- and gender-matched controls were enrolled in the study. The levels of GLP-1, GLP-2, glucose, glycated albumin, insulin, thyroid hormone, and thyroid autoantibodies were measured and evaluated. Results: The levels of GLP-1, blood glucose, and triglyceride were higher in HT patients with subclinical hypothyroidism than in controls (all P < 0.05, respectively. However, the above variables, including GLP-2, were similar in euthyroid patients and controls. Neither GLP-1 nor GLP-2 was correlated with thyroid hormone, thyroid autoantibodies or metabolic parameters. Conclusion: The serum levels of GLP-1, not GLP-2, were increased in patients with subclinical hypothyroidism. Our data suggest that subclinical hypothyroidism affects circulating GLP-1 levels.

  16. Septal Glucagon-Like Peptide 1 Receptor Expression Determines Suppression of Cocaine-Induced Behavior

    Science.gov (United States)

    Harasta, Anne E; Power, John M; von Jonquieres, Georg; Karl, Tim; Drucker, Daniel J; Housley, Gary D; Schneider, Miriam; Klugmann, Matthias

    2015-01-01

    Glucagon-like peptide 1 (GLP-1) and its receptor GLP-1R are a key component of the satiety signaling system, and long-acting GLP-1 analogs have been approved for the treatment of type-2 diabetes mellitus. Previous reports demonstrate that GLP-1 regulates glucose homeostasis alongside the rewarding effects of food. Both palatable food and illicit drugs activate brain reward circuitries, and pharmacological studies suggest that central nervous system GLP-1 signaling holds potential for the treatment of addiction. However, the role of endogenous GLP-1 in the attenuation of reward-oriented behavior, and the essential domains of the mesolimbic system mediating these beneficial effects, are largely unknown. We hypothesized that the central regions of highest Glp-1r gene activity are essential in mediating responses to drugs of abuse. Here, we show that Glp-1r-deficient (Glp-1r−/−) mice have greatly augmented cocaine-induced locomotor responses and enhanced conditional place preference compared with wild-type (Glp-1r+/+) controls. Employing mRNA in situ hybridization we located peak Glp-1r mRNA expression in GABAergic neurons of the dorsal lateral septum, an anatomical site with a crucial function in reward perception. Whole-cell patch-clamp recordings of dorsal lateral septum neurons revealed that genetic Glp-1r ablation leads to increased excitability of these cells. Viral vector-mediated Glp-1r gene delivery to the dorsal lateral septum of Glp-1r−/− animals reduced cocaine-induced locomotion and conditional place preference to wild-type levels. This site-specific genetic complementation did not affect the anxiogenic phenotype observed in Glp-1r−/− controls. These data reveal a novel role of GLP-1R in dorsal lateral septum function driving behavioral responses to cocaine. PMID:25669605

  17. Endogenous Glucagon-like Peptide-1 Receptor Signaling in the Nucleus Tractus Solitarius is Required for Food Intake Control.

    Science.gov (United States)

    Alhadeff, Amber L; Mergler, Blake D; Zimmer, Derek J; Turner, Christopher A; Reiner, David J; Schmidt, Heath D; Grill, Harvey J; Hayes, Matthew R

    2017-06-01

    Alhough the glucagon-like peptide-1 (GLP-1) system is critical to energy balance control and is a target for obesity pharmacotherapies, the receptor-population-mediating effects of endogenous GLP-1 signaling are not fully understood. To address this, we developed a novel adeno-associated virus (AAV-GLP-1R) that utilizes short hairpin RNA to chronically knock down GLP-1 receptors (GLP-1R) in rats. As pharmacological studies highlight the hindbrain nucleus tractus solitarius (NTS) as a brain region important for GLP-1R-mediated effects on energy balance, AAV-GLP-1R was injected into the NTS to examine the role of endogenous NTS GLP-1R signaling in energy balance control. Chow intake and meal size were significantly increased following chronic NTS GLP-1R knockdown. In addition, NTS GLP-1R knockdown significantly increased self-administration of palatable food under both fixed and progressive ratio schedules of reinforcement. Collectively, these data demonstrate that endogenous NTS GLP-1R signaling is required for the control of food intake and motivation to feed, and provide a new strategy to investigate the importance of distinct GLP-1R populations in the control of a variety of functions.

  18. The Effect of Pumpkin on GLP-1 and HOMA-β in Hypercholesterolemic Rats

    Directory of Open Access Journals (Sweden)

    Sunarti

    2016-03-01

    Full Text Available Background and aim: High fat and fructose diet may impair β cell function through oxidative stress that is induced by subsequent hypercholesterolemia. The β cell function is usually quantified by homeostatic model assessment beta-cell function (HOMA-β. Oxidative stress may be decreased by β-carotene from pumpkin (Cucurbita maxima. This study aimed to evaluate the effects of pumpkin powder on glucagon-like peptide-1 (GLP-1 level and HOMA-β in rats with high fat and fructose diet.

  19. Characterization of the glucagon-like peptide-1 receptor in male mouse brain using a novel antibody and in situ hybridization

    DEFF Research Database (Denmark)

    Jensen, Casper Bo; Pyke, Charles; Rasch, Morten Grønbech

    2017-01-01

    was abundantly expressed in numerous regions including the septal nucleus, the hypothalamus and the brain stem. GLP-1R protein expression was also observed on neuronal projections in brain regions devoid of any mRNA which has not been observed in earlier reports. Taken together, these findings provide new......Glucagon-like peptide-1 (GLP-1) is a physiological regulator of appetite and long-acting GLP-1 receptor agonists (GLP-1RA) lower food intake and bodyweight in both human and animal studies. The effects are mediated through brain GLP-1Rs, and several brain nuclei expressing the GLP-1R may...... be involved. To date, mapping the complete location of GLP-1R protein in the brain has been challenged by lack of good antibodies and the discrepancy between mRNA and protein especially relevant in neuronal axonal processes. Here, we present a novel and specific monoclonal GLP-1R antibody...

  20. Agonist-induced internalisation of the glucagon-like peptide-1 receptor is mediated by the Gαq pathway.

    Science.gov (United States)

    Thompson, Aiysha; Kanamarlapudi, Venkateswarlu

    2015-01-01

    The glucagon-like peptide-1 receptor (GLP-1R) is a G-protein-coupled receptor (GPCR) and an important target in the treatment of type 2 diabetes mellitus (T2DM). Upon stimulation with agonist, the GLP-1R signals through both Gαs and Gαq coupled pathways to stimulate insulin secretion. The agonist-induced GLP-1R internalisation has recently been shown to be important for insulin secretion. However, the molecular mechanisms underlying GLP-1R internalisation remain unknown. The aim of this study was to determine the role of GLP-1R downstream signalling pathways in its internalisation. Agonist-induced human GLP-1R (hGLP-1R) internalisation and activity were examined using a number of techniques including immunoblotting, ELISA, immunofluorescence and luciferase assays to determine cAMP production, intracellular Ca(2+) accumulation and ERK phosphorylation. Agonist-induced hGLP-1R internalisation is dependent on caveolin-1 and dynamin. Inhibition of the Gαq pathway but not the Gαs pathway affected hGLP-1R internalisation. Consistent with this, hGLP-1R mutant T149M and small-molecule agonists (compound 2 and compound B), which activate only the Gαs pathway, failed to induce internalisation of the receptor. Chemical inhibitors of the Gαq pathway, PKC and ERK phosphorylation significantly reduced agonist-induced hGLP-1R internalisation. These inhibitors also suppressed agonist-induced ERK1/2 phosphorylation demonstrating that the phosphorylated ERK acts downstream of the Gαq pathway in the hGLP-1R internalisation. In summary, agonist-induced hGLP-1R internalisation is mediated by the Gαq pathway. The internalised hGLP-1R stimulates insulin secretion from pancreatic β-cells, indicating the importance of GLP-1 internalisation for insulin secretion. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Characterization of glucagon-like peptide-1 receptor-binding determinants.

    Science.gov (United States)

    Xiao, Q; Jeng, W; Wheeler, M B

    2000-12-01

    Glucagon-like peptide 1 (GLP-1) is a potent insulinotropic hormone currently under study as a therapeutic agent for type 2 diabetes. Since an understanding of the molecular mechanisms leading to high-affinity receptor (R) binding and activation may facilitate the development of more potent GLP-1R agonists, we have localized specific regions of GLP-1R required for binding. The purified N-terminal fragment (hereafter referred to as NT) of the GLP-1R produced in either insect (Sf9) or mammalian (COS-7) cells was shown to bind GLP-1. The physical interaction of NT with GLP-1 was first demonstrated by cross-linking ((125)I-GLP-1/NT complex band at approximately 28 kDa) and secondly by attachment to Ni(2+)-NTA beads. The GLP-1R NT protein attached to beads bound GLP-1, but with lower affinity (inhibitory concentration (IC(50)): 4.5 x 10(-7) M) than wild-type (WT) GLP-1R (IC(50): 5.2 x 10(-9)M). The low affinity of GLP-1R NT suggested that other receptor domains may contribute to GLP-1 binding. This was supported by studies using chimeric glucose-dependent insulinotropic polypeptide (GIP)/GLP-1 receptors. GIP(1-151)/GLP-1R, but not GIP(1-222)/GLP-1R, exhibited specific GLP-1 binding and GLP-1-induced cAMP production, suggesting that the region encompassing transmembrane (TM) domain 1 through to TM3 was required for binding. Since it was hypothesized that certain charged or polar amino acids in this region might be involved in binding, these residues (TM2-TM3) were analyzed by substitution mutagenesis. Five mutants (K197A, D198A, K202A, D215A, R227A) displayed remarkably reduced binding affinity. These studies indicate that the NT domain of the GLP-1R is able to bind GLP-1, but charged residues concentrated at the distal TM2/extracellular loop-1 (EC1) interface (K197, D198, K202) and in EC1 (D215 and R227) probably contribute to the binding determinants of the GLP-1R.

  2. Physiology and Emerging Biochemistry of the Glucagon-Like Peptide-1 Receptor

    Directory of Open Access Journals (Sweden)

    Francis S. Willard

    2012-01-01

    Full Text Available The glucagon-like peptide-1 (GLP-1 receptor is one of the best validated therapeutic targets for the treatment of type 2 diabetes mellitus (T2DM. Over several years, the accumulation of basic, translational, and clinical research helped define the physiologic roles of GLP-1 and its receptor in regulating glucose homeostasis and energy metabolism. These efforts provided much of the foundation for pharmaceutical development of the GLP-1 receptor peptide agonists, exenatide and liraglutide, as novel medicines for patients suffering from T2DM. Now, much attention is focused on better understanding the molecular mechanisms involved in ligand induced signaling of the GLP-1 receptor. For example, advancements in biophysical and structural biology techniques are being applied in attempts to more precisely determine ligand binding and receptor occupancy characteristics at the atomic level. These efforts should better inform three-dimensional modeling of the GLP-1 receptor that will help inspire more rational approaches to identify and optimize small molecule agonists or allosteric modulators targeting the GLP-1 receptor. This article reviews GLP-1 receptor physiology with an emphasis on GLP-1 induced signaling mechanisms in order to highlight new molecular strategies that help determine desired pharmacologic characteristics for guiding development of future nonpeptide GLP-1 receptor activators.

  3. The cardiovascular safety trials of DPP-4 inhibitors, GLP-1 agonists, and SGLT2 inhibitors.

    Science.gov (United States)

    Secrest, Matthew H; Udell, Jacob A; Filion, Kristian B

    2017-04-01

    In this paper, we review the results of large, double-blind, placebo-controlled randomized trials mandated by the US Food and Drug Administration to examine the cardiovascular safety of newly-approved antihyperglycemic agents in patients with type 2 diabetes. The cardiovascular effects of dipeptidyl peptidase-4 (DPP-4) inhibitors remain controversial: while these drugs did not reduce or increase the risk of primary, pre-specified composite cardiovascular outcomes, one DPP-4 inhibitor (saxagliptin) increased the risk of hospitalization for heart failure in the overall population; another (alogliptin) demonstrated inconsistent effects on heart failure hospitalization across subgroups of patients, and a third (sitagliptin) demonstrated no effect on heart failure. Evidence for cardiovascular benefits of glucagon-like peptide-1 (GLP-1) agonists has been similarly heterogeneous, with liraglutide and semaglutide reducing the risk of composite cardiovascular outcomes, but lixisenatide having no reduction or increase in cardiovascular risk. The effect of GLP-1 agonists on retinopathy remains a potential concern. In the only completed trial to date to assess a sodium-glucose cotransporter-2 (SGLT2) inhibitor, empagliflozin reduced the risk of composite cardiovascular endpoints, predominantly through its impact on cardiovascular mortality and heart failure hospitalization. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Glucagon-like peptide-1 receptor overexpression in cancer and its impact on clinical applications

    Directory of Open Access Journals (Sweden)

    Meike eKörner

    2012-12-01

    Full Text Available Peptide hormones of the glucagon-like peptide (GLP family play an increasing clinical role, such as GLP-1 in diabetes therapy. Moreover, GLP receptors are over-expressed in various human tumor types and therefore represent molecular targets for important clinical applications. In particular, virtually all benign insulinomas highly over-express GLP-1 receptors (GLP-1R. Targeting GLP-1R with the stable GLP-1 analogs 111In-DOTA/ DPTA-exendin-4 offers a new approach to successfully localize these small tumors. This non-invasive technique has the potential to replace the invasive localization of insulinomas by selective arterial stimulation and venous sampling. Malignant insulinomas, in contrast to their benign counterparts, express GLP-1R in only one third of the cases, while they more often express the somatostatin type 2 receptors. Importantly, one of the two receptors appears to be always expressed in malignant insulinomas. The GLP-1R overexpression in selected cancers is worth to be kept in mind with regard to the increasing use of GLP-1 analogs for diabetes therapy. While the functional role of GLP-1R in neoplasia is not known yet, it may be safe to monitore patients undergoing GLP-1 therapy carefully.

  5. Defining the role of GLP-1 in the enteroinsulinar axis in type 2 diabetes using DPP-4 inhibition and GLP-1 receptor blockade

    DEFF Research Database (Denmark)

    Aulinger, Benedikt A; Bedorf, Anne; Kutscherauer, Gabriele

    2014-01-01

    Understanding the incretin pathway has led to significant advancements in the treatment of type 2 diabetes (T2D). Still, the exact mechanisms are not fully understood. In a randomized, placebo-controlled, four-period, crossover study in 24 patients with T2D, dipeptidyl peptidase-4 (DPP-4) inhibit......Understanding the incretin pathway has led to significant advancements in the treatment of type 2 diabetes (T2D). Still, the exact mechanisms are not fully understood. In a randomized, placebo-controlled, four-period, crossover study in 24 patients with T2D, dipeptidyl peptidase-4 (DPP-4...

  6. GLP-1-(9-36) amide reduces blood glucose in anesthetized pigs by a mechanism that does not involve insulin secretion

    DEFF Research Database (Denmark)

    Deacon, Carolyn F; Plamboeck, Astrid; Møller, Søren

    2002-01-01

    impossible to assess its true efficacy in vivo. In chloralose-anesthetized pigs given valine-pyrrolidide (to block endogenous DPP IV activity), the independent effects of GLP-1-(7-36) amide on glucose and insulin responses to intravenous glucose were assessed, and the metabolite generated by DPP IV, GLP-1......-(9-36) amide, was investigated for any ability to influence these responses. GLP-1-(7-36) amide enhanced insulin secretion (P amide was without effect, either alone or when coinfused with GLP-1-(7-36) amide. In contrast, GLP-1-(9-36) amide did affect glucose responses (P...... amide (73 +/- 19 mmol x l(-1) x min; P amide (62 +/- 13 mmol x l(-1) x min; P amide + GLP-1-(9-36) amide (50 +/-13 mmol x l(-1) x min; P

  7. Endogenous GLP-1 mediates postprandial reductions in activation in central reward and satiety areas in patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Ten Kulve, Jennifer S; Veltman, Dick J; van Bloemendaal, Liselotte

    2015-01-01

    Aims/hypothesis The central nervous system (CNS) is a major player in the regulation of food intake. The gut hormone glucagon-like peptide-1 (GLP-1) has been proposed to have an important role in this regulation by relaying information about nutritional status to the CNS. We hypothesised that end......Aims/hypothesis The central nervous system (CNS) is a major player in the regulation of food intake. The gut hormone glucagon-like peptide-1 (GLP-1) has been proposed to have an important role in this regulation by relaying information about nutritional status to the CNS. We hypothesised...... that endogenous GLP-1 has effects on CNS reward and satiety circuits. Methods This was a randomised, crossover, placebo-controlled intervention study, performed in a university medical centre in the Netherlands. We included patients with type 2 diabetes and healthy lean control subjects. Individuals were eligible...

  8. Anti-inflammatory role of GLP-1 and the effect of gastric bypass on diabetes- and obesity-associated inflammation

    DEFF Research Database (Denmark)

    Bovbjerg, Kirsten Katrine Lindegaard

    with a set of metabolic abnormalities comprising the metabolic syndrome, such as hypertension, dyslipidemia, and insulin resistance. Although the exact causes for the onset of clinical disease remain largely unknown, emerging evidence seems to suggest that obesity-induced inflammation, especially...... in the adipose tissue, is involved in the metabolic dysregulation and therefore plays an important role in the pathogenesis of this deteriorating disease.Bariatric surgery, including the Roux-en Y gastric bypass (RYGB), is one of the most effective treatments for severe obesity. In addition to weight loss...... body of literature reports antiinflammatory and other immunological effects of GLP-1 in animals and in humans suggesting that GLP-1 acts beyond purely glucoregulatory mechanisms. The exaggerated postprandial GLP-1 secretion following RYGB may thus be involved in the beneficial metabolic effects both...

  9. GLP1 and glucagon co-secreting pancreatic neuroendocrine tumor presenting as hypoglycemia after gastric bypass

    DEFF Research Database (Denmark)

    Guimarães, Marta; Rodrigues, Pedro; Pereira, Sofia S

    2015-01-01

    for the treatment of severe obesity, a 54-year-old female with previous type 2 diabetes, developed post-prandial sweating, fainting and hypoglycemic episodes, which eventually led to the finding by ultrasound of a 1.8-cm solid mass in the pancreatic head. The 72-h fast test and the plasma chromogranin A levels were...... (471 pmol/g), insulin (139 pmol/g) and somatostatin (23 pmol/g). This is the first report of a GLP1 and glucagon co-secreting pNET presenting as hypoglycemia after gastric bypass surgery. Although pNET are rare, they should be considered in the differential diagnosis of the clinical approach...

  10. Acute but not chronic activation of brain glucagon-like peptide-1 receptors enhances glucose-stimulated insulin secretion in mice.

    Science.gov (United States)

    Tudurí, E; Beiroa, D; Porteiro, B; López, M; Diéguez, C; Nogueiras, R

    2015-08-01

    To investigate the role of brain glucagon-like peptide-1 (GLP-1) in pancreatic β-cell function. To determine the role of brain GLP-1 receptor (GLP-1R) on β-cell function, we administered intracerebroventricular (i.c.v.) infusions of GLP-1 or the specific GLP-1 antagonist exendin-9 (Ex-9), in both an acute and a chronic setting. We observed that acute i.c.v. GLP-1 infusion potentiates glucose-stimulated insulin secretion (GSIS) and improves glucose tolerance, whereas central GLP-1R blockade with Ex-9 impaired glucose excursion after a glucose load. Sustained activation of central nervous system GLP-1R, however, did not produce any effect on either GSIS or glucose tolerance. Similarly, ex vivo GSIS performed in islets from mice chronically infused with i.c.v. GLP-1 resulted in no differences compared with controls. In addition, in mice fed a high-fat diet we observed that acute i.c.v. GLP-1 infusion improved glucose tolerance without changes in GSIS, while chronic GLP-1R activation had no effect on glucose homeostasis. Our results indicate that, under non-clamped conditions, brain GLP-1 plays a functional neuroendocrine role in the acute regulation of glucose homeostasis in both lean and obese rodents. © 2015 John Wiley & Sons Ltd.

  11. Proinsulin, GLP-1, and glucagon are associated with partial remission in children and adolescents with newly diagnosed type 1 diabetes

    DEFF Research Database (Denmark)

    Kaas, A.; Andersen, M. L. M.; Fredheim, Siri

    2012-01-01

    .002) were significantly lower in remitters than in non-remitters at 6 and 12 months. Proinsulin associated positively with GLP-1 at 1 month (p = 0.004) and negatively at 6 (p = 0.002) and 12 months (p = 0.0002). Conclusions: In type 1 diabetes, patients in partial remission have higher levels of proinsulin......1C), glucagon-like peptide-1 (GLP-1), glucagon, and remission status the first year after diagnosis of type 1 diabetes. Methods: Juvenile patients (n = 275) were followed 1, 6, and 12 months after diagnosis. At each visit, partial remission was defined as IDAA1C = 9%. The patients had a liquid meal...

  12. Síndrome metabólico. Asociación entre GLP-1 y factores de riesgo cardiovascular

    OpenAIRE

    Pérez-Durillo, Francsco Tomás

    2017-01-01

    [ES] Objetivos: Determinar la variación de niveles plasmáticos de péptido similar al glucagón (GLP-1) y de actividad dipeptidil peptidasa 4 (DPP4) en pacientes con síndrome metabólico (SM). Diseño: Estudio descriptivo transversal. 46 sujetos (entre 50-65 años) distribuidos en grupo SM y grupo sin SM. Resultados: Los niveles postprandiales de GLP-1 fueron superiores en hombres con SM respecto a las mujeres y en mujeres sin SM respecto a los hombres. Los pacientes diagnosticados de SM de ...

  13. Evidence connecting old, new and neglected glucose-lowering drugs to bile acid-induced GLP-1 secretion

    DEFF Research Database (Denmark)

    Kårhus, Martin L; Brønden, Andreas; Sonne, David P

    2017-01-01

    Bile acids are amphipathic water-soluble steroid-based molecules best known for their important lipid-solubilizing role in the assimilation of fat. Recently, bile acids have emerged as metabolic integrators with glucose-lowering potential. Among a variety of gluco-metabolic effects, bile acids have...... current evidence connecting established glucose-lowering drugs to bile acid-induced GLP-1 secretion and discusses whether bile acid-induced GLP-1 secretion may constitute a new basis for understanding how metformin, inhibitors of the apical sodium-dependent bile acids transporter, and bile acid...... sequestrants - old, new and neglected glucose-lowering drugs - improve glucose metabolism....

  14. Effects of PYY3-36 and GLP-1 on energy intake, energy expenditure and appetite in overweight men

    DEFF Research Database (Denmark)

    Schmidt, Julie Berg; Gregersen, Nikolaj Ture; Pedersen, Sue D

    2014-01-01

    Aim: To examine the effects of GLP-1 and PYY3-36, separately and in combination, on energy intake, energy expenditure, appetite sensations, glucose and fat metabolism, ghrelin and vital signs in healthy overweight men. Methods: 25 healthy, male subjects participated in this randomized, double...... of appetite sensations, energy expenditure and fat oxidation, vital signs and blood variables were collected throughout the infusion period. Results: No effect on energy intake was found after monoinfusions of PYY3-36 (-4.2±4.8%, P=0.8) or GLP-1 (-3.0±4.5%, P=0.9). However, the co-infusion reduced energy...

  15. Effect of GLP-1 on the expression of NADPH oxidase subunits in the kidney of type 1 diabetic rats

    Directory of Open Access Journals (Sweden)

    Jin-jin LIU

    2013-09-01

    Full Text Available Objective To observe the effect of exenatide, a glucagon-like peptide-1 (GLP-1 receptor agonist, on the expression of NADPH oxidase subunits NOX4 and p22phox and connective tissue growth factor (CTGF in the kidney of streptozotocin (STZ-induced type 1 diabetic rats, and explore the protective effects and mechanisms of exenatide on the kidney of diabetic rats. Methods Thirty male Sprague-Dawley (SD rats were divided into control group (group A, n=7 and diabetic model group (n=23. Type 1 diabetic model was reproduced by intraperitoneal injection of streptozotocin. It was successful in 19 rats. Diabetic rats were randomly divided into diabetic control group (group B, n=10 and diabetic with treatment of exenatide group (group C, n=9. Rats in group C were injected subcutaneously with exenatide in dose of 5μg/kg twice daily. Rats in group A and B were given equivalent volume of normal saline by subcutaneous injection. All rats were sacrificed after eight weeks. The mRNA expression of renal p22phox and NOX4 were detected by real-time fluorescence quantitative PCR. The protein expression of CTGF was detected by immunohistochemical staining. Results The levels of blood glucose, lipids, creatinine, and urea nitrogen, the albumin excretion rate, kidney index, the mRNA expressions of renal NOX4 and p22phox, and the protein expression of renal CTGF were significantly increased in group B compared with that in group A (P0.05. Conclusion Exenatide can decrease the expressions of renal NOX4, p22phox and CTGF, decline the index of urinary protein, and alleviate the kidney hypertrophy in type 1 diabetic rats, implying that exenatide exerted a protective effect on the kidney.

  16. GLP-1/glucagon receptor co-agonism for treatment of obesity

    DEFF Research Database (Denmark)

    Sánchez-Garrido, Miguel A.; Brandt, Sara J; Clemmensen, Christoffer

    2017-01-01

    Over a relatively short period, obesity and type 2 diabetes have come to represent a large medical and economic burden to global societies. The epidemic rise in the prevalence of obesity has metabolic consequences and is paralleled by an increased occurrence of other diseases, such as diabetes......, cancer and cardiovascular complications. Together, obesity and type 2 diabetes constitute one of the more preventable causes of premature death and the identification of novel, safe and effective anti-obesity drugs is of utmost importance. Pharmacological attempts to treat obesity have had limited...

  17. Glucagon-Like Peptide-1 and Its Class B G Protein–Coupled Receptors: A Long March to Therapeutic Successes

    Science.gov (United States)

    de Graaf, Chris; Donnelly, Dan; Wootten, Denise; Lau, Jesper; Sexton, Patrick M.; Miller, Laurence J.; Ahn, Jung-Mo; Liao, Jiayu; Fletcher, Madeleine M.; Brown, Alastair J. H.; Zhou, Caihong; Deng, Jiejie; Wang, Ming-Wei

    2016-01-01

    The glucagon-like peptide (GLP)-1 receptor (GLP-1R) is a class B G protein–coupled receptor (GPCR) that mediates the action of GLP-1, a peptide hormone secreted from three major tissues in humans, enteroendocrine L cells in the distal intestine, α cells in the pancreas, and the central nervous system, which exerts important actions useful in the management of type 2 diabetes mellitus and obesity, including glucose homeostasis and regulation of gastric motility and food intake. Peptidic analogs of GLP-1 have been successfully developed with enhanced bioavailability and pharmacological activity. Physiologic and biochemical studies with truncated, chimeric, and mutated peptides and GLP-1R variants, together with ligand-bound crystal structures of the extracellular domain and the first three-dimensional structures of the 7-helical transmembrane domain of class B GPCRs, have provided the basis for a two-domain–binding mechanism of GLP-1 with its cognate receptor. Although efforts in discovering therapeutically viable nonpeptidic GLP-1R agonists have been hampered, small-molecule modulators offer complementary chemical tools to peptide analogs to investigate ligand-directed biased cellular signaling of GLP-1R. The integrated pharmacological and structural information of different GLP-1 analogs and homologous receptors give new insights into the molecular determinants of GLP-1R ligand selectivity and functional activity, thereby providing novel opportunities in the design and development of more efficacious agents to treat metabolic disorders. PMID:27630114

  18. GLP-1 responses are heritable and blunted in acquired obesity with high liver fat and insulin resistance

    DEFF Research Database (Denmark)

    Matikainen, Niina; Bogl, Leonie H; Hakkarainen, Antti

    2014-01-01

    OBJECTIVE Impaired incretin response represents an early and uniform defect in type 2 diabetes, but the contributions of genes and the environment are poorly characterized. RESEARCH DESIGN AND METHODS We studied 35 monozygotic (MZ) and 75 dizygotic (DZ) twin pairs (discordant and concordant for o...... Whereas the GLP-1 response to the OGTT is heritable, an acquired unhealthy pattern of obesity characterized by liver fat accumulation and insulin resistance is closely related to impaired GLP-1 response in young adults....... under the curve was 67% (95% CI 45-80). Cotwins from weight-concordant MZ and DZ pairs and weight-discordant MZ pairs but concordant for liver fat content demonstrated similar glucose, insulin, and incretin profiles after the OGTT and meal tests. In contrast, higher insulin responses and blunted 60-min...... GLP-1 responses during the OGTT were observed in the heavier as compared with leaner MZ cotwins discordant for BMI, liver fat, and insulin sensitivity. Blunted GLP-1 response to OGTT was observed in heavier as compared with leaner DZ cotwins discordant for obesity and insulin sensitivity. CONCLUSIONS...

  19. Glucagon-like peptide-1 (GLP-1) raises blood-brain glucose transfer capacity and hexokinase activity in human brain

    DEFF Research Database (Denmark)

    Gejl, Michael; Lerche, Susanne; Egefjord, Lærke

    2013-01-01

    phosphorylation velocity (V max) in the gray matter regions of cerebral cortex, thalamus, and cerebellum, as well as increased blood-brain glucose transport capacity (T max) in gray matter, white matter, cortex, thalamus, and cerebellum. In hypoglycemia, GLP-1 had no effects on net glucose metabolism, brain...

  20. Weight loss and weight maintenance obtained with or without GLP-1 analogue treatment decrease branched chain amino acid levels

    DEFF Research Database (Denmark)

    Engelbrechtsen, Line; Iepsen, Eva Pers Winning; Galijatovic, Ehm Astrid Andersson

    2016-01-01

    increased during weight loss (p = 5.2 × 10−15) and showed inverse correlation with insulin resistance measured by HOMA–IR levels (r = −0.318, p = 0.025). Valine concentrations were lower in the control group compared to the GLP-1RA group during weight maintenance (p = 0.005). Conclusion Weight loss...

  1. Supplementation with a fish protein hydrolysate (Micromesistius poutassou: effects on body weight, body composition, and CCK/GLP-1 secretion

    Directory of Open Access Journals (Sweden)

    Vincenzo Nobile

    2016-01-01

    Full Text Available Background: Fish protein hydrolysates (FPHs have been reported as a suitable source of proteins for human nutrition because of their balanced amino acid composition and positive effect on gastrointestinal absorption. Objective: Here, we investigated the effect of a FPH, Slimpro®, obtained from blue whiting (Micromesistius poutassou muscle by enzymatic hydrolysis, on body composition and on stimulating cholecystokinin (CCK and glucagon-like peptide-1 (GLP-1 secretion. Design: A randomized clinical study was carried out on 120, slightly overweight (25 kg/m2 ≤ BMI<30 kg/m2, male (25% and female (75% subjects. FPH was tested in a food supplement at two doses (1.4 and 2.8 g to establish if a dose–effect relationship exists. Product use was associated with a mild hypocaloric diet (−300 kcal/day. Body composition (body weight; fat mass; extracellular water; and circumference of waist, thighs, and hips and CCK/GLP-1 blood levels were measured at the beginning of the study and after 45 and 90 days of product use. CCK/GLP-1 levels were measured since they are involved in controlling food intake. Results: Treated subjects reported an improvement of body weight composition and an increased blood concentration of both CCK and GLP-1. No differences were found between the 1.4 and 2.8 g FPH doses, indicating a plateau effect starting from 1.4 g FPH. Conclusions: Both 1.4 and 2.8 g of FPH were effective in improving body composition and in increasing CCK and GLP-1 blood levels.

  2. Synergism by individual macronutrients explains the marked early GLP-1 and islet hormone responses to mixed meal challenge in mice.

    Science.gov (United States)

    Ahlkvist, L; Vikman, J; Pacini, G; Ahrén, B

    2012-10-10

    Apart from glucose, proteins and lipids also stimulate incretin and islet hormone secretion. However, the glucoregulatory effect of macronutrients in combination is poorly understood. We therefore developed an oral mixed meal model in mice to 1) explore the glucagon-like peptide-1 (GLP-1) and islet hormone responses to mixed meal versus isocaloric glucose, and 2) characterize the relative contribution of individual macronutrients to these responses. Anesthetized C57BL/6J female mice were orally gavaged with 1) a mixed meal (0.285 kcal; glucose, whey protein and peanut oil; 60/20/20% kcal) versus an isocaloric glucose load (0.285 kcal), and 2) a mixed meal (0.285 kcal) versus glucose, whey protein or peanut oil administered individually in their mixed meal caloric quantity, i.e., 0.171, 0.055 and 0.055 kcal, respectively. Plasma was analyzed for glucose, insulin and intact GLP-1 before and during oral challenges. Plasma glucose was lower after mixed meal versus after isocaloric glucose ingestion. In spite of this, the peak insulin response (P=0.02), the peak intact GLP-1 levels (P=0.006) and the estimated β-cell function (P=0.005) were higher. Furthermore, the peak insulin (P=0.004) and intact GLP-1 (P=0.006) levels were higher after mixed meal ingestion than the sum of responses to individual macronutrients. Compared to glucose alone, we conclude that there is a marked early insulin response to mixed meal ingestion, which emanates from a synergistic, rather than an additive, effect of the individual macronutrients in the mixed meal and is in part likely caused by increased levels of GLP-1. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. At the centennial of Michaelis and Menten, competing Michaelis-Menten steps explain effect of GLP-1 on blood-brain transfer and metabolism of glucose

    DEFF Research Database (Denmark)

    Jensen, Michael Gejl; Rungby, Jørgen; Brock, Birgitte

    2014-01-01

    Glucagon-like peptide-1 (GLP-1) is a potent insulinotropic incretin hormone with pancreatic and extrapancreatic effects. Studies reveal significant effects in regions of brain tissue that regulate appetite and satiety. The effects cause that mimetics of GLP-1 serves as treatment of type 2 diabete...

  4. Mechanism-based population modelling for assessment of L-cell function based on total GLP-1 response following an oral glucose tolerance test

    DEFF Research Database (Denmark)

    Møller, Jonas B.; Jusko, William J.; Gao, Wei

    2011-01-01

    was to build a mechanism-based population model that describes the time course of total GLP-1 and provides indices for capability of secretion in each subject. The goal was thus to model the secretion of GLP-1, and not its effect on insulin production. Single 75 g doses of glucose were administered orally......GLP-1 is an insulinotropic hormone that synergistically with glucose gives rise to an increased insulin response. Its secretion is increased following a meal and it is thus of interest to describe the secretion of this hormone following an oral glucose tolerance test (OGTT). The aim of this study....... The individual estimates of absorption rate constants were used in the model for GLP-1 secretion. Estimation of parameters was performed using the FOCE method with interaction implemented in NONMEM VI. The final transit/indirect-response model obtained for GLP-1 production following an OGTT included two...

  5. Crystal Structure of Glucagon-like Peptide-1 in Complex with the Extracellular Domain of the Glucagon-like Peptide-1 Receptor*

    Science.gov (United States)

    Underwood, Christina Rye; Garibay, Patrick; Knudsen, Lotte Bjerre; Hastrup, Sven; Peters, Günther H.; Rudolph, Rainer; Reedtz-Runge, Steffen

    2010-01-01

    GLP-1 (glucagon-like peptide-1) is an incretin released from intestinal L-cells in response to food intake. Activation of the GLP-1 receptor potentiates the synthesis and release of insulin from pancreatic β-cells in a glucose-dependent manner. The GLP-1 receptor belongs to class B of the G-protein-coupled receptors, a subfamily characterized by a large N-terminal extracellular ligand binding domain. Exendin-4 and GLP-1 are 50% identical, and exendin-4 is a full agonist with similar affinity and potency for the GLP-1 receptor. We recently solved the crystal structure of the GLP-1 receptor extracellular domain in complex with the competitive antagonist exendin-4(9–39). Interestingly, the isolated extracellular domain binds exendin-4 with much higher affinity than the endogenous agonist GLP-1. Here, we have solved the crystal structure of the extracellular domain in complex with GLP-1 to 2.1 Åresolution. The structure shows that important hydrophobic ligand-receptor interactions are conserved in agonist- and antagonist-bound forms of the extracellular domain, but certain residues in the ligand-binding site adopt a GLP-1-specific conformation. GLP-1 is a kinked but continuous α-helix from Thr13 to Val33 when bound to the extracellular domain. We supplemented the crystal structure with site-directed mutagenesis to link the structural information of the isolated extracellular domain with the binding properties of the full-length receptor. The data support the existence of differences in the binding modes of GLP-1 and exendin-4 on the full-length GLP-1 receptor. PMID:19861722

  6. Crystal structure of glucagon-like peptide-1 in complex with the extracellular domain of the glucagon-like peptide-1 receptor.

    Science.gov (United States)

    Underwood, Christina Rye; Garibay, Patrick; Knudsen, Lotte Bjerre; Hastrup, Sven; Peters, Günther H; Rudolph, Rainer; Reedtz-Runge, Steffen

    2010-01-01

    GLP-1 (glucagon-like peptide-1) is an incretin released from intestinal L-cells in response to food intake. Activation of the GLP-1 receptor potentiates the synthesis and release of insulin from pancreatic beta-cells in a glucose-dependent manner. The GLP-1 receptor belongs to class B of the G-protein-coupled receptors, a subfamily characterized by a large N-terminal extracellular ligand binding domain. Exendin-4 and GLP-1 are 50% identical, and exendin-4 is a full agonist with similar affinity and potency for the GLP-1 receptor. We recently solved the crystal structure of the GLP-1 receptor extracellular domain in complex with the competitive antagonist exendin-4(9-39). Interestingly, the isolated extracellular domain binds exendin-4 with much higher affinity than the endogenous agonist GLP-1. Here, we have solved the crystal structure of the extracellular domain in complex with GLP-1 to 2.1 Aresolution. The structure shows that important hydrophobic ligand-receptor interactions are conserved in agonist- and antagonist-bound forms of the extracellular domain, but certain residues in the ligand-binding site adopt a GLP-1-specific conformation. GLP-1 is a kinked but continuous alpha-helix from Thr(13) to Val(33) when bound to the extracellular domain. We supplemented the crystal structure with site-directed mutagenesis to link the structural information of the isolated extracellular domain with the binding properties of the full-length receptor. The data support the existence of differences in the binding modes of GLP-1 and exendin-4 on the full-length GLP-1 receptor.

  7. Influences of Dietary Added Sugar Consumption on Striatal Food-Cue Reactivity and Postprandial GLP-1 Response

    Directory of Open Access Journals (Sweden)

    Hilary M. Dorton

    2018-01-01

    Full Text Available Sugar consumption in the United States exceeds recommendations from the American Heart Association. Overconsumption of sugar is linked to risk for obesity and metabolic disease. Animal studies suggest that high-sugar diets alter functions in brain regions associated with reward processing, including the dorsal and ventral striatum. Human neuroimaging studies have shown that these regions are responsive to food cues, and that the gut-derived satiety hormones, glucagon-like peptide-1 (GLP-1, and peptide YY (PYY, suppress striatal food-cue responsivity. We aimed to determine the associations between dietary added sugar intake, striatal responsivity to food cues, and postprandial GLP-1 and PYY levels. Twenty-two lean volunteers underwent a functional magnetic resonance imaging (fMRI scan during which they viewed pictures of food and non-food items after a 12-h fast. Before scanning, participants consumed a glucose drink. A subset of 19 participants underwent an additional fMRI session in which they consumed water as a control condition. Blood was sampled for GLP-1, and PYY levels and hunger ratings were assessed before and ~75 min after drink consumption. In-person 24-h dietary recalls were collected from each participant on three to six separate occasions over a 2-month period. Average percent calories from added sugar were calculated using information from 24-h dietary recalls. A region-of-interest analysis was performed to compare the blood oxygen level-dependent (BOLD response to food vs. non-food cues in the bilateral dorsal striatum (caudate/putamen and ventral striatum (nucleus accumbens. The relationships between added sugar, striatal responses, and hormone changes after drink consumption were assessed using Spearman’s correlations. We observed a positive correlation between added sugar intake and BOLD response to food cues in the dorsal striatum and a similar trend in the nucleus accumbens after glucose, but not water, consumption

  8. Preserved GLP-1 and exaggerated GIP secretion in type 2 diabetes and relationships with triglycerides and ALT

    DEFF Research Database (Denmark)

    Alssema, Marjan; Rijkelijkhuizen, Josina M; Holst, Jens Juul

    2013-01-01

    OBJECTIVE: To i) compare incretin responses to oral glucose and mixed meal of diabetic patients with the normoglycaemic population and ii) to investigate whether incretin responses are associated with hypertriglyceridaemia and alanine aminotransferase (ALT) as liver fat marker. DESIGN: A population......-based study. METHODS: A total of 163 persons with normal glucose metabolism (NGM), 20 with intermediate hyperglycaemia and 20 with type 2 diabetes aged 40-65 years participated. Participants received a mixed meal and oral glucose load on separate occasions. Glucagon-like peptide 1 (GLP-1), glucose......-dependent insulinotropic polypeptide (GIP) and glucagon profiles were analysed as total area under the curve (tAUC) and incremental area under the curve. RESULTS: In diabetic patients compared with persons with NGM, we found increased GLP-1 secretion (tAUC per hour) following oral glucose (23.2 pmol/l (95% CI 17...

  9. The effect of a subcutaneous infusion of GLP-1, OXM and PYY on Energy intake and Expenditure in Obese volunteers

    DEFF Research Database (Denmark)

    Tan, Tricia; Behary, Preeshila; Tharakan, George

    2017-01-01

    has been postulated to contribute to its metabolic benefits. Objective: We hypothesised that infusion of the three gut hormones to achieve levels similar to those encountered post-prandially in RYGB patients might be effective in suppressing appetite. The aim of this study was to investigate...... the effect of a continuous infusion of GLP-1, OXM and PYY (GOP) on energy intake and expenditure in obese volunteers. Methods: Obese volunteers were randomised to receive an infusion of GOP or placebo in a single-blinded randomised placebo-controlled cross-over study for 10.5 hours a day. This was delivered......Background: Roux-en-Y gastric bypass (RYGB) surgery is currently the most effective treatment for obesity, although limited by availability and operative risk. The gut hormones Glucagon-like peptide-1 (GLP-1), Peptide YY (PYY) and Oxyntomodulin (OXM) are elevated post-prandially after RYGB, which...

  10. GLP-1 analogue improves hepatic lipid accumulation by inducing autophagy via AMPK/mTOR pathway

    Energy Technology Data Exchange (ETDEWEB)

    He, Qin; Sha, Sha; Sun, Lei; Zhang, Jing; Dong, Ming, E-mail: dr_dongming@126.com

    2016-08-05

    The incidence of nonalcoholic fatty liver disease (NAFLD) keeps rising year by year, and NAFLD is rapidly becoming the most common liver disease worldwide. Clinical studies have found that glucagon-like peptide-1 (GLP-1) analogue, liraglutide (LRG), cannot only reduce glucose levels, but also improve hepatic lipase, especially in patients also with type 2 diabetes mellitus (T2DM). In addition, enhancing autophagy decreases lipid accumulation in hepatocytes. The aim of the present study is to explore the effect of LRG on hepatocyte steatosis and the possible role of autophagy. We set up an obesity mouse model with a high-fat diet (HFD) and induced hepatocyte steatosis with free fatty acids (FFA) in human L-O2 cells. LRG and two inhibitors of autophagy, Chloroquine (CQ) and bafilomycin A1 (Baf), were added into each group, respectively. The lipid profiles and morphological modifications of each group were tested. Immunohistochemistry, immunofluorescence staining and transmission electron microscopy (TEM) were used to measure autophagy in this study. The autophagy protein expression of SQSTM1 (P62), and LC3B, along with the signaling pathway proteins of mTOR, phosphorylated mTOR (p-mTOR), AMPK, phosphorylated AMPK (p-AMPK) and Beclin1, were evaluated by western blot. Our results showed that LRG improved hepatocyte steatosis by inducing autophagy, and the AMPK/mTOR pathway is involved. These findings suggest an important mechanism for the positive effects of LRG on hepatic steatosis, and provide new evidence for clinical use of LRG in NAFLD. -- Highlights: •Liraglutide reduces lipid accumulation in hepatic steatosis both in vivo and in vitro. •Autophagy was involved in relieving effects of liraglutide on hepatic steatosis. •AMPK/mTOR pathway was involved in liraglutide-induced autophagy.

  11. GLP-1 analogue improves hepatic lipid accumulation by inducing autophagy via AMPK/mTOR pathway

    International Nuclear Information System (INIS)

    He, Qin; Sha, Sha; Sun, Lei; Zhang, Jing; Dong, Ming

    2016-01-01

    The incidence of nonalcoholic fatty liver disease (NAFLD) keeps rising year by year, and NAFLD is rapidly becoming the most common liver disease worldwide. Clinical studies have found that glucagon-like peptide-1 (GLP-1) analogue, liraglutide (LRG), cannot only reduce glucose levels, but also improve hepatic lipase, especially in patients also with type 2 diabetes mellitus (T2DM). In addition, enhancing autophagy decreases lipid accumulation in hepatocytes. The aim of the present study is to explore the effect of LRG on hepatocyte steatosis and the possible role of autophagy. We set up an obesity mouse model with a high-fat diet (HFD) and induced hepatocyte steatosis with free fatty acids (FFA) in human L-O2 cells. LRG and two inhibitors of autophagy, Chloroquine (CQ) and bafilomycin A1 (Baf), were added into each group, respectively. The lipid profiles and morphological modifications of each group were tested. Immunohistochemistry, immunofluorescence staining and transmission electron microscopy (TEM) were used to measure autophagy in this study. The autophagy protein expression of SQSTM1 (P62), and LC3B, along with the signaling pathway proteins of mTOR, phosphorylated mTOR (p-mTOR), AMPK, phosphorylated AMPK (p-AMPK) and Beclin1, were evaluated by western blot. Our results showed that LRG improved hepatocyte steatosis by inducing autophagy, and the AMPK/mTOR pathway is involved. These findings suggest an important mechanism for the positive effects of LRG on hepatic steatosis, and provide new evidence for clinical use of LRG in NAFLD. -- Highlights: •Liraglutide reduces lipid accumulation in hepatic steatosis both in vivo and in vitro. •Autophagy was involved in relieving effects of liraglutide on hepatic steatosis. •AMPK/mTOR pathway was involved in liraglutide-induced autophagy.

  12. Acute activation of GLP-1-expressing neurons promotes glucose homeostasis and insulin sensitivity.

    Science.gov (United States)

    Shi, Xuemei; Chacko, Shaji; Li, Feng; Li, Depei; Burrin, Douglas; Chan, Lawrence; Guan, Xinfu

    2017-11-01

    Glucagon-like peptides are co-released from enteroendocrine L cells in the gut and preproglucagon (PPG) neurons in the brainstem. PPG-derived GLP-1/2 are probably key neuroendocrine signals for the control of energy balance and glucose homeostasis. The objective of this study was to determine whether activation of PPG neurons per se modulates glucose homeostasis and insulin sensitivity in vivo. We generated glucagon (Gcg) promoter-driven Cre transgenic mice and injected excitatory hM3Dq-mCherry AAV into their brainstem NTS. We characterized the metabolic impact of PPG neuron activation on glucose homeostasis and insulin sensitivity using stable isotopic tracers coupled with hyperinsulinemic euglycemic clamp. We showed that after ip injection of clozapine N-oxide, Gcg-Cre lean mice transduced with hM3Dq in the brainstem NTS downregulated basal endogenous glucose production and enhanced glucose tolerance following ip glucose tolerance test. Moreover, acute activation of PPG neurons NTS enhanced whole-body insulin sensitivity as indicated by increased glucose infusion rate as well as augmented insulin-suppression of endogenous glucose production and gluconeogenesis. In contrast, insulin-stimulation of glucose disposal was not altered significantly. We conclude that acute activation of PPG neurons in the brainstem reduces basal glucose production, enhances intraperitoneal glucose tolerance, and augments hepatic insulin sensitivity, suggesting an important physiological role of PPG neurons-mediated circuitry in promoting glycemic control and insulin sensitivity. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

  13. Oxyntomodulin differentially affects glucagon-like peptide-1 receptor beta-arrestin recruitment and signaling through Galpha(s)

    DEFF Research Database (Denmark)

    Jorgensen, Rasmus; Kubale, Valentina; Vrecl, Milka

    2007-01-01

    The glucagon-like peptide (GLP)-1 receptor is a promising target for the treatment of type 2 diabetes and obesity, and there is great interest in characterizing the pharmacology of the GLP-1 receptor and its ligands. In the present report, we have applied bioluminescence resonance energy transfer...

  14. The Antidiabetic Mechanisms of Polyphenols Related to Increased Glucagon-Like Peptide-1 (GLP1 and Insulin Signaling

    Directory of Open Access Journals (Sweden)

    J. Abraham Domínguez Avila

    2017-05-01

    Full Text Available Type-2 diabetes mellitus (T2DM is an endocrine disease related to impaired/absent insulin signaling. Dietary habits can either promote or mitigate the onset and severity of T2DM. Diets rich in fruits and vegetables have been correlated with a decreased incidence of T2DM, apparently due to their high polyphenol content. Polyphenols are compounds of plant origin with several documented bioactivities related to health promotion. The present review describes the antidiabetic effects of polyphenols, specifically related to the secretion and effects of insulin and glucagon-like peptide 1 (GLP1, an enteric hormone that stimulates postprandial insulin secretion. The evidence suggests that polyphenols from various sources stimulate L-cells to secrete GLP1, increase its half-life by inhibiting dipeptidyl peptidase-4 (DPP4, stimulate β-cells to secrete insulin and stimulate the peripheral response to insulin, increasing the overall effects of the GLP1-insulin axis. The glucose-lowering potential of polyphenols has been evidenced in various acute and chronic models of healthy and diabetic organisms. Some polyphenols appear to exert their effects similarly to pharmaceutical antidiabetics; thus, rigorous clinical trials are needed to fully validate this claim. The broad diversity of polyphenols has not allowed for entirely describing their mechanisms of action, but the evidence advocates for their regular consumption.

  15. Impact of Diabetes-Specific Nutritional Formulas versus Oatmeal on Postprandial Glucose, Insulin, GLP-1 and Postprandial Lipidemia

    Directory of Open Access Journals (Sweden)

    Adham Mottalib

    2016-07-01

    Full Text Available Diabetes-specific nutritional formulas (DSNFs are frequently used as part of medical nutrition therapy for patients with diabetes. This study aims to evaluate postprandial (PP effects of 2 DSNFs; Glucerna (GL and Ultra Glucose Control (UGC versus oatmeal (OM on glucose, insulin, glucagon-like peptide-1 (GLP-1, free fatty acids (FFA and triglycerides (TG. After an overnight fast, 22 overweight/obese patients with type 2 diabetes were given 200 kcal of each of the three meals on three separate days in random order. Blood samples were collected at baseline and at 30, 60, 90, 120, 180 and 240 min. Glucose area under the curve (AUC0–240 after GL and UGC was lower than OM (p < 0.001 for both. Insulin positive AUC0–120 after UGC was higher than after OM (p = 0.02. GLP-1 AUC0–120 and AUC0–240 after GL and UGC was higher than after OM (p < 0.001 for both. FFA and TG levels were not different between meals. Intake of DSNFs improves PP glucose for 4 h in comparison to oatmeal of similar caloric level. This is achieved by either direct stimulation of insulin secretion or indirectly by stimulating GLP-1 secretion. The difference between their effects is probably related to their unique blends of amino acids, carbohydrates and fat.

  16. Increased Postprandial GIP and Glucagon Responses, But Unaltered GLP-1 Response after Intervention with Steroid Hormone, Relative Physical Inactivity, And High-Calorie Diet in Healthy Subjects

    DEFF Research Database (Denmark)

    Hansen, Katrine B; Vilsbøll, Tina; Bagger, Jonatan I

    2011-01-01

    Objective:Increased postprandial glucose-dependent insulinotropic polypeptide (GIP) and glucagon responses and reduced postprandial glucagon-like peptide-1 (GLP-1) responses have been observed in some patients with type 2 diabetes mellitus. The causality of these pathophysiological traits...... postprandial GLP-1 responses as observed in some individuals with type 2 diabetes mellitus....... is unknown. We aimed to determine the impact of insulin resistance and reduced glucose tolerance on postprandial GIP, GLP-1, and glucagon responses in healthy subjects. Research Design and Methods:A 4-h 2200 KJ-liquid meal test was performed in 10 healthy Caucasian males without family history of diabetes...

  17. COUP-TFII controls mouse pancreatic β-cell mass through GLP-1-β-catenin signaling pathways.

    Directory of Open Access Journals (Sweden)

    Marie Boutant

    Full Text Available The control of the functional pancreatic β-cell mass serves the key homeostatic function of releasing the right amount of insulin to keep blood sugar in the normal range. It is not fully understood though how β-cell mass is determined.Conditional chicken ovalbumin upstream promoter transcription factor II (COUP-TFII-deficient mice were generated and crossed with mice expressing Cre under the control of pancreatic duodenal homeobox 1 (pdx1 gene promoter. Ablation of COUP-TFII in pancreas resulted in glucose intolerance. Beta-cell number was reduced at 1 day and 3 weeks postnatal. Together with a reduced number of insulin-containing cells in the ductal epithelium and normal β-cell proliferation and apoptosis, this suggests decreased β-cell differentiation in the neonatal period. By testing islets isolated from these mice and cultured β-cells with loss and gain of COUP-TFII function, we found that COUP-TFII induces the expression of the β-catenin gene and its target genes such as cyclin D1 and axin 2. Moreover, induction of these genes by glucagon-like peptide 1 (GLP-1 via β-catenin was impaired in absence of COUP-TFII. The expression of two other target genes of GLP-1 signaling, GLP-1R and PDX-1 was significantly lower in mutant islets compared to control islets, possibly contributing to reduced β-cell mass. Finally, we demonstrated that COUP-TFII expression was activated by the Wnt signaling-associated transcription factor TCF7L2 (T-cell factor 7-like 2 in human islets and rat β-cells providing a feedback loop.Our findings show that COUP-TFII is a novel component of the GLP-1 signaling cascade that increases β-cell number during the neonatal period. COUP-TFII is required for GLP-1 activation of the β-catenin-dependent pathway and its expression is under the control of TCF7L2.

  18. GLP-1 Response to Oral Glucose is Reduced in Pre-diabetes, Screen-detected Type 2 Diabetes, and Obesity and Influenced by Sex

    DEFF Research Database (Denmark)

    Færch, Kristine; Torekov, Signe S; Vistisen, Dorte

    2015-01-01

    concentrations of glucose, insulin and GLP-1 during an oral glucose tolerance test (OGTT) were analyzed in individuals with normal glucose tolerance (NGT, n=774), pre-diabetes (n=523) or screen-detected type 2 diabetes (n=163) who attended the Danish ADDITION-PRO study (n=1,462). Compared with individuals...... with NGT, women with pre-diabetes or type 2 diabetes had 25% lower GLP-1 response to an OGTT, and both men and women with pre-diabetes or type 2 diabetes had 16-21% lower 120-min GLP-1 concentrations independent of age and obesity. Obese and overweight individuals had 20% reduced GLP-1 response to oral...

  19. Enhanced glucagon-like peptide-1 (GLP-1) response to oral glucose in glucose-intolerant HIV-infected patients on antiretroviral therapy

    DEFF Research Database (Denmark)

    Andersen, O; Haugaard, S B; Holst, Jens Juul

    2005-01-01

    concentrations of GLP-1 and GIP were determined frequently during a 3-h, 75-g glucose tolerance test. Insulin secretion rates (ISRs) were calculated by deconvolution of C-peptide concentrations. RESULTS: The incremental area under the curve (incrAUC) for GLP-1 was increased by 250% in IGT patients compared...... without adjustment (r=0.38, Pglucose incrAUC (r=0.49, Pglucose-intolerant, HIV-infected male patients may display enhanced GLP-1 responses to oral glucose compared with normal glucose-tolerant HIV-infected male patients......OBJECTIVES: We investigated whether the incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), which are major regulators of glucose tolerance through the stimulation of insulin secretion, contribute to impaired glucose tolerance (IGT) among HIV...

  20. An overview of once-weekly glucagon-like peptide-1 receptor agonists--available efficacy and safety data and perspectives for the future

    DEFF Research Database (Denmark)

    Madsbad, S; Kielgast, U; Asmar, M

    2011-01-01

    Incretin-based therapies, such as the injectable glucagon-like peptide-1 (GLP-1) receptor agonists and orally administered dipeptidyl peptidase-4 (DPP-4) inhibitors, have recently been introduced into clinical practice. At present, the GLP-1 receptor agonists need to be administered once or twice...

  1. Brain reward-system activation in response to anticipation and consumption of palatable food is altered by glucagon-like peptide-1 receptor activation in humans

    NARCIS (Netherlands)

    van Bloemendaal, L.; Veltman, D. J.; ten Kulve, J. S.; Groot, P. F. C.; Ruhe, H. G.; Barkhof, F.; Sloan, J. H.; Diamant, M.; Ijzerman, R. G.

    AimTo test the hypothesis that food intake reduction after glucagon-like peptide-1 (GLP-1) receptor activation is mediated through brain areas regulating anticipatory and consummatory food reward. MethodsAs part of a larger study, we determined the effects of GLP-1 receptor activation on brain

  2. Brain reward-system activation in response to anticipation and consumption of palatable food is altered by glucagon-like peptide-1 receptor activation in humans

    NARCIS (Netherlands)

    van Bloemendaal, L.; Veltman, D. J.; ten Kulve, J. S.; Groot, P. F. C.; Ruhé, H. G.; Barkhof, F.; Sloan, J. H.; Diamant, M.; Ijzerman, R. G.

    2015-01-01

    To test the hypothesis that food intake reduction after glucagon-like peptide-1 (GLP-1) receptor activation is mediated through brain areas regulating anticipatory and consummatory food reward. As part of a larger study, we determined the effects of GLP-1 receptor activation on brain responses to

  3. Brain reward-system activation in response to anticipation and consumption of palatable food is altered by glucagon-like peptide-1 receptor activation in humans

    NARCIS (Netherlands)

    van Bloemendaal, L.; Veltman, D.J.; ten Kulve, J.S.; Groot, P.F.C.; Ruhe, H.G.; Barkhof, F.; Sloan, J.H.; Diamant, M.; IJzerman, R.G.

    2015-01-01

    Aim: To test the hypothesis that food intake reduction after glucagon-like peptide-1 (GLP-1) receptor activation is mediated through brain areas regulating anticipatory and consummatory food reward. Methods: As part of a larger study, we determined the effects of GLP-1 receptor activation on brain

  4. Comparison Review of Short-Acting and Long-Acting Glucagon-like Peptide-1 Receptor Agonists.

    Science.gov (United States)

    Uccellatore, Annachiara; Genovese, Stefano; Dicembrini, Ilaria; Mannucci, Edoardo; Ceriello, Antonio

    2015-09-01

    Glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1 RAs) are useful tools for treating type 2 diabetes mellitus. In their recent position statement, the American Diabetes Association and European Association for the Study of Diabetes recommend GLP1-RAs as add-on to metformin when therapeutic goals are not achieved with monotherapy, particularly for patients who wish to avoid weight gain or hypoglycemia. GLP1-RAs differ substantially in their duration of action, frequency of administration and clinical profile. Members of this class approved for clinical use include exenatide twice-daily, exenatide once-weekly, liraglutide and lixisenatide once-daily. Recently, two new once-weekly GLP1-RAs have been approved: dulaglutide and albiglutide. This article summarizes properties of short- and long-acting GLP-1 analogs, and provides useful information to help choose the most appropriate compound for individual patients.

  5. Real-time trafficking and signaling of the glucagon-like peptide-1 receptor

    DEFF Research Database (Denmark)

    Roed, Sarah Noerklit; Wismann, Pernille; Underwood, Christina Rye

    2014-01-01

    The glucagon-like peptide-1 incretin receptor (GLP-1R) of family B G protein-coupled receptors (GPCRs) is a major drug target in type-2-diabetes due to its regulatory effect on post-prandial blood-glucose levels. The mechanism(s) controlling GLP-1R mediated signaling are far from fully understood....... A fundamental mechanism controlling the signaling capacity of GPCRs is the post-endocytic trafficking of receptors between recycling and degradative fates. Here, we combined microscopy with novel real-time assays to monitor both receptor trafficking and signaling in living cells. We find that the human GLP-1R...

  6. Niveles de GLP-1 tras el test de sobrecarga oral de glucosa en mujeres con antecedentes de diabetes mellitus gestacional

    OpenAIRE

    Maraver Selfa, Silvia María

    2017-01-01

    Se ha descrito una reducción significativa del efecto incretina en pacientes con DM2 que puede deberse a la secreción alterada de las hormonas incretinas y/o a una acción insulinotrópica defectuosa de las mismas. Podría plantearse que este efecto incretina deteriorado en pacientes con trastornos del metabolismo hidrocarbonado, fuese un defecto primario precoz que preceda al desarrollo de la DM2, o secundario a la propia hiperglucemia. Objetivos. Estudiar el patrón de secreción de GLP-1 ...

  7. Benefits and challenges of a QSP approach through case study: Evaluation of a hypothetical GLP-1/GIP dual agonist therapy.

    Science.gov (United States)

    Rieger, Theodore R; Musante, Cynthia J

    2016-10-30

    Quantitative Systems Pharmacology (QSP) is an emerging science with increasing application to pharmaceutical research and development paradigms. Through case study we provide an overview of the benefits and challenges of applying QSP approaches to inform program decisions in the early stages of drug discovery and development. Specifically, we describe the use of a type 2 diabetes systems model to inform a No-Go decision prior to lead development for a potential GLP-1/GIP dual agonist program, enabling prioritization of exploratory programs with higher probability of clinical success. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  8. Circadian rhythms of GIP and GLP1 in glucose-tolerant and in type 2 diabetic patients after biliopancreatic diversion

    DEFF Research Database (Denmark)

    Mingrone, G; Nolfe, G; Gissey, G Castagneto

    2009-01-01

    AIMS/HYPOTHESIS: We tested the hypothesis that the reversibility of insulin resistance and diabetes observed after biliopancreatic diversion (BPD) is related to changes in circadian rhythms of gastrointestinal hormones. METHODS: Ten morbidly obese participants, five with normal glucose tolerance......(-1)). CONCLUSIONS/INTERPRETATION: An incretin circadian rhythm was shown for the first time in morbid obesity. The effect of BPD on the 24 h pattern of incretin differed between NGT and diabetic patients. GLP1 secretion impairment was reversed in NGT and could not be overcome by surgery in diabetes...

  9. Proglucagon Promoter Cre-Mediated AMPK Deletion in Mice Increases Circulating GLP-1 Levels and Oral Glucose Tolerance.

    Directory of Open Access Journals (Sweden)

    Sophie R Sayers

    Full Text Available Enteroendocrine L-cells synthesise and release the gut hormone glucagon-like peptide-1 (GLP-1 in response to food transit. Deletion of the tumour suppressor kinase LKB1 from proglucagon-expressing cells leads to the generation of intestinal polyps but no change in circulating GLP-1 levels. Here, we explore the role of the downstream kinase AMP-activated protein kinase (AMPK in these cells.Loss of AMPK from proglucagon-expressing cells was achieved using a preproglucagon promoter-driven Cre (iGluCre to catalyse recombination of floxed alleles of AMPKα1 and α2. Oral and intraperitoneal glucose tolerance were measured using standard protocols. L-cell mass was measured by immunocytochemistry. Hormone and peptide levels were measured by electrochemical-based luminescence detection or radioimmunoassay.Recombination with iGluCre led to efficient deletion of AMPK from intestinal L- and pancreatic alpha-cells. In contrast to mice rendered null for LKB1 using the same strategy, mice deleted for AMPK displayed an increase (WT: 0.05 ± 0.01, KO: 0.09±0.02%, p<0.01 in L-cell mass and elevated plasma fasting (WT: 5.62 ± 0.800 pg/ml, KO: 14.5 ± 1.870, p<0.01 and fed (WT: 15.7 ± 1.48pg/ml, KO: 22.0 ± 6.62, p<0.01 GLP-1 levels. Oral, but not intraperitoneal, glucose tolerance was significantly improved by AMPK deletion, whilst insulin and glucagon levels were unchanged despite an increase in alpha to beta cell ratio (WT: 0.23 ± 0.02, KO: 0.33 ± 0.03, p<0.01.AMPK restricts L-cell growth and GLP-1 secretion to suppress glucose tolerance. Targeted inhibition of AMPK in L-cells may thus provide a new therapeutic strategy in some forms of type 2 diabetes.

  10. Pancreatic beta-cell responses to GLP-1 after near-normalization of blood glucose in patients with type 2 diabetes.

    Science.gov (United States)

    Asmar, Meena; Højberg, Patricia V; Deacon, Carolyn F; Hare, Kristine; Holst, Jens J; Madsbad, Sten

    2010-02-25

    This study investigated the effects of strict glycaemic control on beta-cell function in nine obese subjects with type 2 diabetes (T2DM), using graded glucose infusions together with infusions of saline or GLP-1 before (HbA(1)c: 8.0+/-0.4%) and after four weeks of near-normalization of blood glucose (BG) using insulin (mean diurnal BG: 6.4+/-0.3 mmol/l; HbA(1)c: 6.6+/-0.3%). Nine matched healthy subjects acted as controls. In controls, area-under-curve (AUC) for amylin, C-peptide and proinsulin were higher with GLP-1 than saline (PAUC amylin/C-peptide ratio was similar on both days, while AUC proinsulin/C-peptide ratio was higher with GLP-1 (P=0.02). In the patients, amylin, C-peptide and proinsulin AUCs were unaltered by near-normoglycaemia per se. Proinsulin responses to GLP-1 were unchanged, but amylin and C-peptide AUCs increased (PAUC amylin/C-peptide ratios rose to control levels. Near-normoglycaemia tended to reduce AUC proinsulin/C-peptide ratio, which was significant (P=0.04) with GLP-1, but still higher than with saline (P=0.004). In conclusion, amylin, C-peptide and proinsulin responses to glucose were unaffected by four weeks of near-normoglycaemia, whereas GLP-1 increased amylin and C-peptide secretion and amylin/C-peptide ratio. Near-normoglycaemia reduced proinsulin/C-peptide ratio during stimulation with GLP-1, suggesting that strict glycaemic control might ameliorate some of the disturbances in beta-cell function characterizing T2DM. Copyright 2010 Elsevier B.V. All rights reserved.

  11. Glucagon-Like Peptide-1 Receptor Agonists for the Treatment of Type 2 Diabetes Mellitus: A Position Statement of the Korean Diabetes Association

    Directory of Open Access Journals (Sweden)

    Hyun Jin Kim

    2017-12-01

    Full Text Available The glucagon-like peptide-1 receptor agonists (GLP-1RAs were recommended as a monotherapy or combination therapy with oral hypoglycemic agents or basal insulin in the position statement of the Korean Diabetes Association 2017 for pharmacological therapy. Many randomized clinical trials and systematic reviews report that GLP-1RAs have considerable glucose-lowering effect and lead to weight reduction and low risk of hypoglycemia when used as a monotherapy or combination therapy. The cardiovascular safety of GLP-1RAs has been assessed in several randomized clinical trials and systematic reviews. The results of cardiovascular outcome trials of long-acting GLP-1RAs (liraglutide, semaglutide demonstrated cardiovascular benefits in subjects with type 2 diabetes mellitus and a high risk of cardiovascular disease. The GLP-1RA may be a choice of therapy when weight control and avoidance of hypoglycemia are important, and patients with high risk of cardiovascular disease might also favor choosing GLP-1RA.

  12. A high carbohydrate, but not fat or protein meal attenuates postprandial ghrelin, PYY and GLP-1 responses in Chinese men.

    Directory of Open Access Journals (Sweden)

    Ehsan Parvaresh Rizi

    Full Text Available It is known that the macronutrient content of a meal has different impacts on the postprandial satiety and appetite hormonal responses. Whether obesity interacts with such nutrient-dependent responses is not well characterized. We examined the postprandial appetite and satiety hormonal responses after a high-protein (HP, high-carbohydrate (HC, or high-fat (HF mixed meal. This was a randomized cross-over study of 9 lean insulin-sensitive (mean±SEM HOMA-IR 0.83±0.10 and 9 obese insulin-resistant (HOMA-IR 4.34±0.41 young (age 21-40 years, normoglycaemic Chinese men. We measured fasting and postprandial plasma concentration of glucose, insulin, active glucagon-like peptide-1 (GLP-1, total peptide-YY (PYY, and acyl-ghrelin in response to HP, HF, or HC meals. Overall postprandial plasma insulin response was more robust in the lean compared to obese subjects. The postprandial GLP-1 response after HF or HP meal was higher than HC meal in both lean and obese subjects. In obese subjects, HF meal induced higher response in postprandial PYY compared to HC meal. HP and HF meals also suppressed ghrelin greater compared to HC meal in the obese than lean subjects. In conclusion, a high-protein or high-fat meal induces a more favorable postprandial satiety and appetite hormonal response than a high-carbohydrate meal in obese insulin-resistant subjects.

  13. A high carbohydrate, but not fat or protein meal attenuates postprandial ghrelin, PYY and GLP-1 responses in Chinese men

    Science.gov (United States)

    Parvaresh Rizi, Ehsan; Loh, Tze Ping; Baig, Sonia; Chhay, Vanna; Huang, Shiqi; Caleb Quek, Jonathan; Tai, E. Shyong; Toh, Sue-Anne

    2018-01-01

    It is known that the macronutrient content of a meal has different impacts on the postprandial satiety and appetite hormonal responses. Whether obesity interacts with such nutrient-dependent responses is not well characterized. We examined the postprandial appetite and satiety hormonal responses after a high-protein (HP), high-carbohydrate (HC), or high-fat (HF) mixed meal. This was a randomized cross-over study of 9 lean insulin-sensitive (mean±SEM HOMA-IR 0.83±0.10) and 9 obese insulin-resistant (HOMA-IR 4.34±0.41) young (age 21–40 years), normoglycaemic Chinese men. We measured fasting and postprandial plasma concentration of glucose, insulin, active glucagon-like peptide-1 (GLP-1), total peptide-YY (PYY), and acyl-ghrelin in response to HP, HF, or HC meals. Overall postprandial plasma insulin response was more robust in the lean compared to obese subjects. The postprandial GLP-1 response after HF or HP meal was higher than HC meal in both lean and obese subjects. In obese subjects, HF meal induced higher response in postprandial PYY compared to HC meal. HP and HF meals also suppressed ghrelin greater compared to HC meal in the obese than lean subjects. In conclusion, a high-protein or high-fat meal induces a more favorable postprandial satiety and appetite hormonal response than a high-carbohydrate meal in obese insulin-resistant subjects. PMID:29385178

  14. Role of lateral septum glucagon-like peptide 1 receptors in food intake.

    Science.gov (United States)

    Terrill, Sarah J; Jackson, Christine M; Greene, Hayden E; Lilly, Nicole; Maske, Calyn B; Vallejo, Samantha; Williams, Diana L

    2016-07-01

    Hindbrain glucagon-like peptide 1 (GLP-1) neurons project to numerous forebrain areas, including the lateral septum (LS). Using a fluorescently labeled GLP-1 receptor (GLP-1R) agonist, Exendin 4 (Ex4), we demonstrated GLP-1 receptor binding throughout the rat LS. We examined the feeding effects of Ex4 and the GLP-1R antagonist Exendin (9-39) (Ex9) at doses subthreshold for effect when delivered to the lateral ventricle. Intra-LS Ex4 suppressed overnight chow and high-fat diet (HFD) intake, and Ex9 increased chow and HFD intake relative to vehicle. During 2-h tests, intra-LS Ex9 significantly increased 0.25 M sucrose and 4% corn oil. Ex4 can cause nausea, but intra-LS administration of Ex4 did not induce pica. Furthermore, intra-LS Ex4 had no effect on anxiety-like behavior in the elevated plus maze. We investigated the role of LS GLP-1R in motivation for food by examining operant responding for sucrose on a progressive ratio (PR) schedule, with and without a nutrient preload to maximize GLP-1 neuron activation. The preload strongly suppressed PR responding, but blockade of GLP-1R in the intermediate subdivision of the LS did not affect motivation for sucrose under either load condition. The ability of the nutrient load to suppress subsequent chow intake was significantly attenuated by intermediate LS Ex9 treatment. By contrast, blockade of GLP-1R in the dorsal subdivision of the LS increased both PR responding and overnight chow intake. Together, these studies suggest that endogenous activity of GLP-1R in the LS influence feeding, and dLS GLP-1Rs, in particular, play a role in motivation. Copyright © 2016 the American Physiological Society.

  15. Normalization of fasting glycaemia by intravenous GLP-1 ([7-36 amide] or [7-37]) in type 2 diabetic patients

    DEFF Research Database (Denmark)

    Nauck, M A; Weber, I; Bach, I

    1998-01-01

    (glucose-oxidase), insulin and C-peptide (ELISA) was measured during infusion and for 4 h thereafter. Indirect calorimetry was performed. Fasting hyperglycaemia was 11.7+/-0.9 [7-36 amide] and 11.3+/-0.9 mmol l(-1) [7-37]. GLP-1 infusions stimulated insulin secretion approximately 3-fold (insulin peak 168......Intravenous GLP-1 [7-36 amide] can normalize fasting hyperglycaemia in Type 2 diabetic patients. Whether GLP-1 [7-37] has similar effects and how quickly plasma glucose concentrations revert to hyperglycaemia after stopping GLP-1 is not known. Therefore, 8 patients with Type 2 diabetes (5 female, 3...... male; 65+/-6 years; BMI 34.3+/-7.9 kg m(-2); HbA1c 9.6+/-1.2%; treatment with diet alone (n=2), sulphonylurea (n=5), metformin (n=1)) were examined twice in randomized order. GLP-1 [7-36 amide] or [7-37] (1 pmol kg(-1)min(-1) were infused intravenously over 4 h in fasted subjects. Plasma glucose...

  16. CORRELATION BETWEEN PRE AND POSTOPERATIVE LEVELS OF GLP-1/GLP-2 AND WEIGHT LOSS AFTER ROUX-EN-Y GASTRIC BYPASS: A PROSPECTIVE STUDY

    Science.gov (United States)

    CAZZO, Everton; GESTIC, Martinho Antonio; UTRINI, Murillo Pimentel; PAREJA, José Carlos; CHAIM, Elinton Adami; GELONEZE, Bruno; BARRETO, Maria Rita Lazzarini; MAGRO, Daniéla Oliveira

    2016-01-01

    ABSTRACT Background: The role of gut hormones in glucose homeostasis and weight loss achievement and maintenance after bariatric surgery appears to be a key point in the understanding of the beneficial effects observed following these procedures. Aim: To determine whether there is a correlation between the pre and postoperative levels of both GLP-1 and GLP-2 and the excess weight loss after Roux-en-Y gastric bypass (RYGB). Methods: An exploratory prospective study which enrolled 11 individuals who underwent RYGB and were followed-up for 12 months. GLP-1 and GLP-2 after standard meal tolerance test (MTT) were determined before and after surgery and then correlated with the percentage of excess loss (%EWL). Results: GLP-2 AUC presented a significant postoperative increase (945.3±449.1 vs.1787.9±602.7; p=0.0037); GLP-1 AUC presented a non-significant trend towards increase after RYGB (709.6±320.4 vs. 1026.5±714.3; p=0.3808). Mean %EWL was 66.7±12.2%. There was not any significant correlation between both the pre and postoperative GLP-1 AUCs and GLP-2 AUCs and the %EWL achieved after one year. Conclusion: There was no significant correlation between the pre and postoperative levels of the areas under the GLP-1 and GLP-2 curves with the percentage of weight loss reached after one year. PMID:28076481

  17. Loss of Cyp8b1 Improves Glucose Homeostasis by Increasing GLP-1

    NARCIS (Netherlands)

    Kaur, Achint; Patankar, Jay V.; de Haan, Willeke; Ruddle, Piers; Wijesekara, Nadeeja; Groen, Albert K.; Verchere, C. Bruce; Singaraja, Roshni R.; Hayden, Michael R.

    Besides their role in facilitating lipid absorption, bile acids are increasingly being recognized as signaling molecules that activate cell-signaling receptors. Targeted disruption of the sterol 12-hydroxylase gene (Cyp8b1) results in complete absence of cholic acid (CA) and its derivatives. Here we

  18. Glucagon-like peptide-1 receptor ligand interactions: structural cross talk between ligands and the extracellular domain.

    Directory of Open Access Journals (Sweden)

    Graham M West

    Full Text Available Activation of the glucagon-like peptide-1 receptor (GLP-1R in pancreatic β-cells potentiates insulin production and is a current therapeutic target for the treatment of type 2 diabetes mellitus (T2DM. Like other class B G protein-coupled receptors (GPCRs, the GLP-1R contains an N-terminal extracellular ligand binding domain. N-terminal truncations on the peptide agonist generate antagonists capable of binding to the extracellular domain, but not capable of activating full length receptor. The main objective of this study was to use Hydrogen/deuterium exchange (HDX to identify how the amide hydrogen bonding network of peptide ligands and the extracellular domain of GLP-1R (nGLP-1R were altered by binding interactions and to then use this platform to validate direct binding events for putative GLP-1R small molecule ligands. The HDX studies presented here for two glucagon-like peptide-1 receptor (GLP-1R peptide ligands indicates that the antagonist exendin-4[9-39] is significantly destabilized in the presence of nonionic detergents as compared to the agonist exendin-4. Furthermore, HDX can detect stabilization of exendin-4 and exendin-4[9-39] hydrogen bonding networks at the N-terminal helix [Val19 to Lys27] upon binding to the N-terminal extracellular domain of GLP-1R (nGLP-1R. In addition we show hydrogen bonding network stabilization on nGLP-1R in response to ligand binding, and validate direct binding events with the extracellular domain of the receptor for putative GLP-1R small molecule ligands.

  19. A major lineage of enteroendocrine cells coexpress CCK, secretin, GIP, GLP-1, PYY, and neurotensin but not somatostatin

    DEFF Research Database (Denmark)

    Egerod, Kristoffer Lihme; Engelstoft, Maja Storm; Grunddal, Kaare Villum

    2012-01-01

    Enteroendocrine cells such as duodenal cholecystokinin (CCK cells) are generally thought to be confined to certain segments of the gastrointestinal (GI) tract and to store and release peptides derived from only a single peptide precursor. In the current study, however, transgenic mice expressing...... enhanced green fluorescent protein (eGFP) under the control of the CCK promoter demonstrated a distribution pattern of CCK-eGFP positive cells that extended throughout the intestine. Quantitative PCR and liquid chromatography-mass spectrometry proteomic analyses of isolated, FACS-purified CCK-eGFP-positive...... to coexpress members of a group of functionally related peptides: CCK, secretin, GIP, GLP-1, PYY, and neurotensin, suggesting a potential therapeutic target for the treatment and prevention of diabetes and obesity....

  20. Distal gastrectomy in pancreaticoduodenectomy is associated with accelerated gastric emptying, enhanced postprandial release of GLP-1, and improved insulin sensitivity

    DEFF Research Database (Denmark)

    Harmuth, Stefan; Wewalka, Marlene; Holst, Jens Juul

    2014-01-01

    resistance (HOMA-IR) and oral glucose insulin sensitivity were calculated from glucose and insulin concentrations. RESULTS: Patients with Whipple procedure as compared to PPPD had accelerated gastric emptying (p = 0.01) which correlated with early (0-30 min) integrated GLP-1 (AUC30; r (2) = 0.61; p = 0.......02) and insulin sensitivity (r (2) = 0.41; p = 0.026) and inversely with HOMA-IR (r (2) = 0.17; p = 0.033). Two of 13 Whipple patients (15 %) as compared to seven of 13 after PPPD (54 %) had postload glucose concentrations (i.e. 120 min postmeal) ≥200 mg/dl (p 

  1. Acute effects of glucagon-like peptide-1, GLP-19-36 amide, and exenatide on mesenteric blood flow, cardiovascular parameters, and biomarkers in healthy volunteers

    DEFF Research Database (Denmark)

    Hansen, Lasse Bremholm; Andersen, Ulrik B; Hornum, Mads

    2017-01-01

    arteries. GLP-1 significantly increased heart rate (two-way ANOVA, injection [P = 0.0162], time [P = 0.0038], and injection × time [P = 0.082]; Tukey post hoc GLP-1 vs. saline and GLP-19-36amide [P stroke volume compared to GLP-19-36 amide...... subcutaneous injections of GLP-1, GLP-19-36 amide (bioactive metabolite), exenatide (stable GLP-1 agonist), or saline on four separate days. Blood flow in mesenteric, celiac, and renal arteries was measured by Doppler ultrasound. Blood pressure, heart rate, cardiac output, and stroke volume were measured...

  2. Antidiabetic actions of endogenous and exogenous GLP-1 in type 1 diabetic patients with and without residual ß-cell function

    DEFF Research Database (Denmark)

    Kielgast, Urd; Holst, Jens Juul; Madsbad, Sten

    2011-01-01

    To investigate the effect of exogenous as well as endogenous glucagon-like peptide 1 (GLP-1) on postprandial glucose excursions and to characterize the secretion of incretin hormones in type 1 diabetic patients with and without residual ß-cell function.......To investigate the effect of exogenous as well as endogenous glucagon-like peptide 1 (GLP-1) on postprandial glucose excursions and to characterize the secretion of incretin hormones in type 1 diabetic patients with and without residual ß-cell function....

  3. Glucagon-like peptide-1 receptor agonists for the treatment of type 2 diabetes

    DEFF Research Database (Denmark)

    Lund, Asger; Knop, Filip K; Vilsbøll, Tina

    2014-01-01

    Glucagon-like peptide-1 (GLP-1) is a gastrointestinal hormone, secreted in response to ingestion of nutrients, and has important effects on several of the pathophysiological features of type 2 diabetes (T2D). The effects include potentiation of insulin secretion, suppression of glucagon secretion...... effects. This review gives an overview of the clinical data on GLP-1R agonists that have been compared in head-to-head studies and focuses on relevant differences between the compounds. Highlighting these similarities and differences could be beneficial for physicians in choosing the best treatment......, slowing of gastric emptying and suppression of appetite. In circulation, GLP-1 has a half-life of approximately 2min due to rapid degradation by the enzyme dipeptidyl peptidase 4 (DPP-4). Because of this short half-life GLP-1 receptor (GLP-1R) agonists, resistant to degradation by DPP-4 have been...

  4. GLUT2 and the incretin receptors are involved in glucose-induced incretin secretion

    DEFF Research Database (Denmark)

    Cani, Patrice D; Holst, Jens Juul; Drucker, Daniel J

    2007-01-01

    to those described for beta-cells, brain and hepatoportal sensors. We determined the role of GLUT2, GLP-1 or GIP receptors in glucose-induced incretins secretion, in the corresponding knockout mice. GLP-1 secretion was reduced in all mutant mice, while GIP secretion did not require GLUT2. Intestinal GLP-1...... content was reduced only in GIP and GLUT2 receptors knockout mice suggesting that this impairment could contribute to the phenotype. Intestinal GIP content was similar in all mice studied. Furthermore, the impaired incretins secretion was associated with a reduced glucose-stimulated insulin secretion...

  5. Liraglutide: a once-daily GLP-1 analogue for the treatment of type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Vilsbøll, Tina

    2007-01-01

    properties that are suitable for once-daily dosing. Liraglutide has demonstrated lasting improvement of HbA(1c )levels, weight reduction and improved beta-cell function in patients with Type 2 diabetes mellitus. Liraglutide is well tolerated; the adverse events that are most frequently reported being...... transient nausea and diarrhoea. This article reviews the mechanisms of action and efficacy of liraglutide for the treatment of Type 2 diabetes mellitus. This agent is presently in Phase III clinical development.......The incretin hormones are intestinal peptides that enhance insulin secretion following ingestion of nutrients. Liraglutide is a glucagon-like peptide-1 receptor analogue, which is obtained by derivatising glucagon-like peptide-1 with a fatty acid, providing a compound with pharmacokinetic...

  6. Liraglutide: a once-daily GLP-1 analogue for the treatment of type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Vilsbøll, Tina

    2007-01-01

    The incretin hormones are intestinal peptides that enhance insulin secretion following ingestion of nutrients. Liraglutide is a glucagon-like peptide-1 receptor analogue, which is obtained by derivatising glucagon-like peptide-1 with a fatty acid, providing a compound with pharmacokinetic propert...... transient nausea and diarrhoea. This article reviews the mechanisms of action and efficacy of liraglutide for the treatment of Type 2 diabetes mellitus. This agent is presently in Phase III clinical development....... properties that are suitable for once-daily dosing. Liraglutide has demonstrated lasting improvement of HbA(1c )levels, weight reduction and improved beta-cell function in patients with Type 2 diabetes mellitus. Liraglutide is well tolerated; the adverse events that are most frequently reported being...

  7. The influence of GLP-1 on glucose-stimulated insulin secretion: effects on beta-cell sensitivity in type 2 and nondiabetic subjects

    DEFF Research Database (Denmark)

    Kjems, Lise L; Holst, Jens J; 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. Effects of fat supplementation on postprandial GIP, GLP-1, ghrelin and IGFBP-1 levels: a pilot study on adolescents with type 1 diabetes

    DEFF Research Database (Denmark)

    Lodefalk, M; Carlsson-Skwirut, C; Holst, Jens Juul

    2010-01-01

    Aims: To compare the responses of GIP, GLP-1, ghrelin and IGFBP-1 between meals with different fat and energy content in adolescents with type 1 diabetes (T1DM) and to relate them to gastric emptying and glycaemia. Methods: On different days and in a random order, 7 adolescents with T1DM ingested...... by the paracetamol absorption method. Results: The area under the curve (AUC) for GIP(0-240 min) and for GLP-1(0-120 min) was larger, but smaller for relative ghrelin(0-240 min), after the high-fat meal (p = 0.002, 0.030 and 0.043, respectively). IGFBP-1 decreased significantly, but not differently, after the meals....... Larger GLP-1 secretion correlated with slower gastric emptying (p = 0.029) and higher fasting ghrelin levels correlated with lower postprandial glycaemia (p = 0.007). Conclusion: In adolescents with T1DM, the postprandial responses of GIP, GLP-1 and ghrelin, but not that of IGFBP-1, depend more on meal...

  9. Serum lipase activity and concentration during intravenous infusions of GLP-1 and PYY3-36 and after ad libitum meal ingestion in overweight men

    DEFF Research Database (Denmark)

    Schmidt, Julie Berg; Sjödin, Anders Mikael; Stevner, Lene Susanne

    2016-01-01

    To examine the effect on serum lipase activity and protein concentration of intravenous infusions of glucagon-like peptide-1 (GLP-1) and peptide YY (PYY3-36) and of an ad libitum meal in healthy overweight men. Twenty-five healthy, male subjects participated in this randomized, double-blinded, pl......To examine the effect on serum lipase activity and protein concentration of intravenous infusions of glucagon-like peptide-1 (GLP-1) and peptide YY (PYY3-36) and of an ad libitum meal in healthy overweight men. Twenty-five healthy, male subjects participated in this randomized, double...... the infusion and after intake of an ad libitum meal for measurement of serum lipase. Serum lipase levels measured by enzyme-linked immunosorbent assay (ELISA) following mono-infusions of GLP-1 and PYY3-36 were comparable to serum lipase levels following placebo (P = 0.054 and P = 0.873, respectively......). Following the co-infusion of GLP-1 and PYY3-36, serum lipase levels measured by ELISA decreased over time compared to placebo (P = 0.012). However, the between-group difference was not consistent when each time point was analyzed separately. On the placebo day, serum lipase levels measured by ELISA after...

  10. Current evidence for a role of GLP-1 in Roux-en-Y gastric bypass-induced remission of type 2 diabetes

    DEFF Research Database (Denmark)

    Rhee, Nicolai Alexander; Vilsbøll, T; Knop, F K

    2012-01-01

    Weight-reducing surgical procedures such as Roux-en-Y gastric bypass (RYGB) have proven efficient as means of decreasing excess body weight. Furthermore, some studies report that up to 80% of patients with type 2 diabetes mellitus (T2DM) undergoing RYGB experience complete remission of their T2DM......-induced remission of T2DM are lacking. This article critically evaluates the current evidence for a role of GLP-1 in RYGB-induced remission of T2DM.......Weight-reducing surgical procedures such as Roux-en-Y gastric bypass (RYGB) have proven efficient as means of decreasing excess body weight. Furthermore, some studies report that up to 80% of patients with type 2 diabetes mellitus (T2DM) undergoing RYGB experience complete remission of their T2DM...... antidiabetic effects of GLP-1 are thought to be key mediators in RYGB-induced remission of T2DM. However, the published studies on the impact of RYGB on GLP-1 secretion are few, small and often not controlled properly. Furthermore, mechanistic studies delineating the role of endogenous GLP-1 secretion in RYGB...

  11. The effects of aerobic exercises and 25(OH D supplementation on GLP1 and DPP4 level in Type II diabetic patients

    Directory of Open Access Journals (Sweden)

    Naser Rahimi

    2017-01-01

    Full Text Available Background: The purpose of this study was to investigate the effects of an 8-week aerobic exercise and supplementation of 25(OHD3 on GLP1 and DDP4 levels in men with type II diabetes. Methods: In this semiexperimental research, among 40–60-year-old men with type II diabetes who were referred to the diabetic center of Isabn-E Maryam hospital in Isfahan; of whom, 48 patients were voluntarily accepted and then were randomly divided into 4 groups: aerobic exercise group, aerobic exercise with 25(OH D supplement group, 25(OH D supplement group, and the control group. An aerobic exercise program was conducted for 8 weeks (3 sessions/week, each session 60 to75 min with 60–80% HRmax. The supplement user group received 50,000 units of oral Vitamin D once weekly for 8 weeks. The GLP1, DPP4, and 25(OH D levels were measured before and after the intervention. At last, the data were statistically analyzed using the ANCOVA and post hoc test of least significant difference. Results: The results of ANCOVA showed a significant difference between the GLP1 and DPP4 levels in aerobic exercise with control group while these changes were not statistically significant between the 25(OH D supplement group with control group (P < 0.05. Conclusions: Aerobic exercises have resulted an increase in GLP1 level and a decrease in DPP4 level. However, consumption of Vitamin D supplement alone did not cause any changes in GLP1and DPP4 levels but led to an increase in 25-hydroxy Vitamin D level.

  12. In vivo dual-delivery of glucagon like peptide-1 (GLP-1) and dipeptidyl peptidase-4 (DPP4) inhibitor through composites prepared by microfluidics for diabetes therapy

    Science.gov (United States)

    Araújo, F.; Shrestha, N.; Gomes, M. J.; Herranz-Blanco, B.; Liu, D.; Hirvonen, J. J.; Granja, P. L.; Santos, H. A.; Sarmento, B.

    2016-05-01

    Oral delivery of proteins is still a challenge in the pharmaceutical field. Nanoparticles are among the most promising carrier systems for the oral delivery of proteins by increasing their oral bioavailability. However, most of the existent data regarding nanosystems for oral protein delivery is from in vitro studies, lacking in vivo experiments to evaluate the efficacy of these systems. Herein, a multifunctional composite system, tailored by droplet microfluidics, was used for dual delivery of glucagon like peptide-1 (GLP-1) and dipeptidyl peptidase-4 inhibitor (iDPP4) in vivo. Oral delivery of GLP-1 with nano- or micro-systems has been studied before, but the simultaneous nanodelivery of GLP-1 with iDPP4 is a novel strategy presented here. The type 2 diabetes mellitus (T2DM) rat model, induced through the combined administration of streptozotocin and nicotinamide, a non-obese model of T2DM, was used. The combination of both drugs resulted in an increase in the hypoglycemic effects in a sustained, but prolonged manner, where the iDPP4 improved the therapeutic efficacy of GLP-1. Four hours after the oral administration of the system, blood glucose levels were decreased by 44%, and were constant for another 4 h, representing half of the glucose area under the curve when compared to the control. An enhancement of the plasmatic insulin levels was also observed 6 h after the oral administration of the dual-drug composite system and, although no statistically significant differences existed, the amount of pancreatic insulin was also higher. These are promising results for the oral delivery of GLP-1 to be pursued further in a chronic diabetic model study.

  13. Excessive islet NO generation in type 2 diabetic GK rats coincides with abnormal hormone secretion and is counteracted by GLP-1.

    Directory of Open Access Journals (Sweden)

    Albert Salehi

    Full Text Available BACKGROUND: A distinctive feature of type 2 diabetes is inability of insulin-secreting beta-cells to properly respond to elevated glucose eventually leading to beta-cell failure. We have hypothesized that an abnormally increased NO production in the pancreatic islets might be an important factor in the pathogenesis of beta-cell dysfunction. PRINCIPAL FINDINGS: We show now that islets of type 2 spontaneous diabetes in GK rats display excessive NO generation associated with abnormal iNOS expression in insulin and glucagon cells, increased ncNOS activity, impaired glucose-stimulated insulin release, glucagon hypersecretion, and impaired glucose-induced glucagon suppression. Pharmacological blockade of islet NO production by the NOS inhibitor N(G-nitro-L-arginine methyl ester (L-NAME greatly improved hormone secretion from GK islets suggesting islet NOS activity being an important target to inactivate for amelioration of islet cell function. The incretin hormone GLP-1, which is used in clinical practice suppressed iNOS and ncNOS expression and activity with almost full restoration of insulin release and partial restoration of glucagon release. GLP-1 suppression of iNOS expression was reversed by PKA inhibition but unaffected by the proteasome inhibitor MG132. Injection of glucose plus GLP-1 in the diabetic rats showed that GLP-1 amplified the insulin response but induced a transient increase and then a poor depression of glucagon. CONCLUSION: The results suggest that abnormally increased NO production within islet cells is a significant player in the pathogenesis of type 2 diabetes being counteracted by GLP-1 through PKA-dependent, nonproteasomal mechanisms.

  14. Sucralose enhances GLP-1 release and lowers blood glucose in the presence of carbohydrate in healthy subjects but not in patients with type 2 diabetes.

    Science.gov (United States)

    Temizkan, S; Deyneli, O; Yasar, M; Arpa, M; Gunes, M; Yazici, D; Sirikci, O; Haklar, G; Imeryuz, N; Yavuz, D G

    2015-02-01

    Artificial sweeteners were thought to be metabolically inactive, but after demonstrating that the gustatory mechanism was also localized in the small intestine, suspicions about the metabolic effects of artificial sweeteners have emerged. The objective of this study was to determine the effect of artificial sweeteners (aspartame and sucralose) on blood glucose, insulin, c-peptide and glucagon-like peptide-1 (GLP-1) levels. Eight newly diagnosed drug-naive type 2 diabetic patients (mean age 51.5±9.2 years; F/M: 4/4) and eight healthy subjects (mean age 45.0±4.1 years; F/M: 4/4) underwent 75 g oral glucose tolerance test (OGTT). During OGTT, glucose, insulin, c-peptide and GLP-1 were measured at 15- min intervals for 120 min. The OGTTs were performed at three settings on different days, where subjects were given 72 mg of aspartame and 24 mg of sucralose in 200 ml of water or 200 ml of water alone 15 min before OGTT in a single-blinded randomized order. In healthy subjects, the total area under the curve (AUC) of glucose was statistically significantly lower in the sucralose setting than in the water setting (P=0.002). There was no difference between the aspartame setting and the water setting (P=0.53). Total AUC of insulin and c-peptide was similar in aspartame, sucralose and water settings. Total AUC of GLP-1 was significantly higher in the sucralose setting than in the water setting (P=0.04). Total AUC values of glucose, insulin, c-peptide and GLP-1 were not statistically different in three settings in type 2 diabetic patients. Sucralose enhances GLP-1 release and lowers blood glucose in the presence of carbohydrate in healthy subjects but not in newly diagnosed type 2 diabetic patients.

  15. The glucagon-like peptide-1 receptor in the ventromedial hypothalamus reduces short-term food intake in male mice by regulating nutrient sensor activity.

    Science.gov (United States)

    Burmeister, Melissa A; Brown, Jacob D; Ayala, Jennifer E; Stoffers, Doris A; Sandoval, Darleen A; Seeley, Randy J; Ayala, Julio E

    2017-12-01

    Pharmacological activation of the glucagon-like peptide-1 receptor (GLP-1R) in the ventromedial hypothalamus (VMH) reduces food intake. Here, we assessed whether suppression of food intake by GLP-1R agonists (GLP-1RA) in this region is dependent on AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR). We found that pharmacological inhibition of glycolysis, and thus activation of AMPK, in the VMH attenuates the anorectic effect of the GLP-1R agonist exendin-4 (Ex4), indicating that glucose metabolism and inhibition of AMPK are both required for this effect. Furthermore, we found that Ex4-mediated anorexia in the VMH involved mTOR but not acetyl-CoA carboxylase, two downstream targets of AMPK. We support this by showing that Ex4 activates mTOR signaling in the VMH and Chinese hamster ovary (CHO)-K1 cells. In contrast to the clear acute pharmacological impact of the these receptors on food intake, knockdown of the VMH Glp1r conferred no changes in energy balance in either chow- or high-fat-diet-fed mice, and the acute anorectic and glucose tolerance effects of peripherally dosed GLP-1RA were preserved. These results show that the VMH GLP-1R regulates food intake by engaging key nutrient sensors but is dispensable for the effects of GLP-1RA on nutrient homeostasis. Copyright © 2017 the American Physiological Society.

  16. Would glucagon-like peptide-1 receptor agonists have efficacy in binge eating disorder and bulimia nervosa? A review of the current literature.

    Science.gov (United States)

    McElroy, Susan L; Mori, Nicole; Guerdjikova, Anna I; Keck, Paul E

    2018-02-01

    Binge eating, eating an abnormally large amount of food in a discrete period of time with a sense of loss of control over eating, is a defining feature of the eating disorders binge eating disorder (BED) and bulimia nervosa (BN). Both BED and BN are important public health problems for which there are few medical treatments. However, almost all drugs with central nervous system-mediated weight loss properties studied thus far in randomized, placebo-controlled trials in persons with BED or BN have been efficacious for reducing binge eating behavior. Glucagon-like peptide-1 (GLP-1) receptor agonists, marketed for type 2 diabetes and chronic weight management, produce weight loss in a dose dependent manner and have favorable psychiatric adverse event profiles. We hypothesize that GLP-1 receptor agonists will safely reduce binge eating behavior in individuals with BED or BN, including those with co-occurring psychiatric disorders, and propose that randomized, placebo-controlled clinical trials of GLP-1 receptor agonists be conducted in persons with BED and those with BN. To support this hypothesis, we review studies of GLP-1 and GLP-1 receptor agonists in preclinical models of binge eating, studies of GLP-1 levels in individuals with BED or BN, and preliminary data of GLP-1 receptor agonists in humans with abnormal eating behavior. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. GLP-1 analogues for neuroprotection after out-of-hospital cardiac arrest: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Wiberg, Sebastian; Hassager, Christian; Thomsen, Jakob Hartvig; Frydland, Martin; Høfsten, Dan Eik; Engstrøm, Thomas; Køber, Lars; Schmidt, Henrik; Møller, Jacob Eifer; Kjaergaard, Jesper

    2016-06-30

    Attenuating the neurological damage occurring after out-of-hospital cardiac arrest is an ongoing research effort. This dual-centre study investigates the neuroprotective effects of the glucagon-like-peptide-1 analogue Exenatide administered within 4 hours from the return of spontaneous circulation to comatose patients resuscitated from out-of-hospital cardiac arrest. This pilot study will randomize a total of 120 unconscious patients with sustained return of spontaneous circulation after out-of-hospital cardiac arrest undergoing targeted temperature management in a blinded one-to-one fashion to a 6-hour and 15-minute infusion of either Exenatide or placebo. Patients are eligible for inclusion if resuscitated from cardiac arrest with randomization from 20 minutes to 240 minutes after return of spontaneous circulation. The co-primary endpoint is feasibility, defined as the initiation of treatment within the inclusion window in more than 90 % of participants, and efficacy, defined as the area under the neuron-specific enolase curve from 0 to 72 hours after admission. Secondary endpoints include all-cause mortality at 30 days and Cerebral Performance Category as well as a modified Rankin Score at 180 days. The study has been approved by the Danish National Board of Health and the local Ethics Committee and is monitored by Good Clinical Practice units. The study is currently enrolling. This paper presents the methods and planned statistical analyses used in the GLP-1 trial and aims to minimize bias and data-driven reporting of results. 1) Danish National Board of Health, EudraCT 2013-004311-45. Registered on 25 March 2014. 2) Videnskabsetisk komité C, Region Hovedstaden, No. 45728. Registered on 29 January 2014. 3) Clinicaltrial.gov, NCT02442791 . Registered on 25 of January 2015.

  18. A tripeptide Diapin effectively lowers blood glucose levels in male type 2 diabetes mice by increasing blood levels of insulin and GLP-1.

    Directory of Open Access Journals (Sweden)

    Jifeng Zhang

    Full Text Available The prevalence of type 2 diabetes (T2D is rapidly increasing worldwide. Effective therapies, such as insulin and Glucagon-like peptide-1 (GLP-1, require injections, which are costly and result in less patient compliance. Here, we report the identification of a tripeptide with significant potential to treat T2D. The peptide, referred to as Diapin, is comprised of three natural L-amino acids, GlyGlyLeu. Glucose tolerance tests showed that oral administration of Diapin effectively lowered blood glucose after oral glucose loading in both normal C57BL/6J mice and T2D mouse models, including KKay, db/db, ob/ob mice, and high fat diet-induced obesity/T2D mice. In addition, Diapin treatment significantly reduced casual blood glucose in KKay diabetic mice in a time-dependent manner without causing hypoglycemia. Furthermore, we found that plasma GLP-1 and insulin levels in diabetic models were significantly increased with Diapin treatment compared to that in the controls. In summary, our findings establish that a peptide with minimum of three amino acids can improve glucose homeostasis and Diapin shows promise as a novel pharmaceutical agent to treat patients with T2D through its dual effects on GLP-1 and insulin secretion.

  19. Both GLP-1 and GIP are insulinotropic at basal and postprandial glucose levels and contribute nearly equally to the incretin effect of a meal in healthy subjects

    DEFF Research Database (Denmark)

    Vilsbøll, Tina; Krarup, Thure; Madsbad, Sten

    2003-01-01

    was to evaluate this. Eight healthy male volunteers (mean age: 23 (range 20-25) years; mean body mass index: 22.2 (range 19.3-25.4) kg/m2) participated in studies involving stepwise glucose clamping at fasting plasma glucose levels and at 6 and 7 mmol/l. Physiological amounts of either GIP (1.5 pmol/kg/min), GLP......-1(7-36)amide (0.33 pmol/kg/min) or saline were infused for three periods of 30 min at each glucose level, with 1 h "washout" between the infusions. On a separate day, a standard meal test (566 kcal) was performed. During the meal test, peak insulin concentrations were observed after 30 min...... and amounted to 223+/-27 pmol/l. Glucose+saline infusions induced only minor increases in insulin concentrations. GLP-1 and GIP infusions induced significant and similar increases at fasting glucose levels and at 6 mmol/l. At 7 mmol/l, further increases were seen, with GLP-1 effects exceeding those of GIP...

  20. Pancreatic beta-cell responses to GLP-1 after near-normalization of blood glucose in patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Asmar, Meena; Højberg, Patricia V; Deacon, Carolyn F

    2010-01-01

    glucose (BG) using insulin (mean diurnal BG: 6.4+/-0.3 mmol/l; HbA(1)c: 6.6+/-0.3%). Nine matched healthy subjects acted as controls. In controls, area-under-curve (AUC) for amylin, C-peptide and proinsulin were higher with GLP-1 than saline (PAUC amylin/C-peptide ratio was similar on both......This study investigated the effects of strict glycaemic control on beta-cell function in nine obese subjects with type 2 diabetes (T2DM), using graded glucose infusions together with infusions of saline or GLP-1 before (HbA(1)c: 8.0+/-0.4%) and after four weeks of near-normalization of blood...... amylin/C-peptide ratios rose to control levels. Near-normoglycaemia tended to reduce AUC proinsulin/C-peptide ratio, which was significant (P=0.04) with GLP-1, but still higher than with saline (P=0.004). In conclusion, amylin, C-peptide and proinsulin responses to glucose were unaffected by four weeks...

  1. Pancreatic ß-cell responses to GLP-1 after near-normalization of blood glucose in patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Asmar, Meena; Højberg, Patricia; Deacon, Carolyn F.

    2010-01-01

    glucose (BG) using insulin (mean diurnal BG: 6.4+/-0.3 mmol/l; HbA(1)c: 6.6+/-0.3%). Nine matched healthy subjects acted as controls. In controls, area-under-curve (AUC) for amylin, C-peptide and proinsulin were higher with GLP-1 than saline (PAUC amylin/C-peptide ratio was similar on both......This study investigated the effects of strict glycaemic control on beta-cell function in nine obese subjects with type 2 diabetes (T2DM), using graded glucose infusions together with infusions of saline or GLP-1 before (HbA(1)c: 8.0+/-0.4%) and after four weeks of near-normalization of blood...... amylin/C-peptide ratios rose to control levels. Near-normoglycaemia tended to reduce AUC proinsulin/C-peptide ratio, which was significant (P=0.04) with GLP-1, but still higher than with saline (P=0.004). In conclusion, amylin, C-peptide and proinsulin responses to glucose were unaffected by four weeks...

  2. Discovery of dual-action membrane-anchored modulators of incretin receptors.

    Directory of Open Access Journals (Sweden)

    Jean-Philippe Fortin

    Full Text Available The glucose-dependent insulinotropic polypeptide (GIP and the glucagon-like peptide-1 (GLP-1 receptors are considered complementary therapeutic targets for type 2 diabetes. Using recombinant membrane-tethered ligand (MTL technology, the present study focused on defining optimized modulators of these receptors, as well as exploring how local anchoring influences soluble peptide function.Serial substitution of residue 7 in membrane-tethered GIP (tGIP led to a wide range of activities at the GIP receptor, with [G(7]tGIP showing enhanced efficacy compared to the wild type construct. In contrast, introduction of G(7 into the related ligands, tGLP-1 and tethered exendin-4 (tEXE4, did not affect signaling at the cognate GLP-1 receptor. Both soluble and tethered GIP and GLP-1 were selective activators of their respective receptors. Although soluble EXE4 is highly selective for the GLP-1 receptor, unexpectedly, tethered EXE4 was found to be a potent activator of both the GLP-1 and GIP receptors. Diverging from the pharmacological properties of soluble and tethered GIP, the newly identified GIP-R agonists, (i.e. [G(7]tGIP and tEXE4 failed to trigger cognate receptor endocytosis. In an attempt to recapitulate the dual agonism observed with tEXE4, we conjugated soluble EXE4 to a lipid moiety. Not only did this soluble peptide activate both the GLP-1 and GIP receptors but, when added to receptor expressing cells, the activity persists despite serial washes.These findings suggest that conversion of a recombinant MTL to a soluble membrane anchored equivalent offers a means to prolong ligand function, as well as to design agonists that can simultaneously act on more than one therapeutic target.

  3. Effects of gastric inhibitory polypeptide, glucagon-like peptide-1 and glucagon-like peptide-1 receptor agonists on Bone Cell Metabolism.

    Science.gov (United States)

    Hansen, Morten S S; Tencerova, Michaela; Frølich, Jacob; Kassem, Moustapha; Frost, Morten

    2018-01-01

    The relationship between gut and skeleton is increasingly recognized as part of the integrated physiology of the whole organism. The incretin hormones gastric inhibitory polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are secreted from the intestine in response to nutrient intake and exhibit several physiological functions including regulation of islet hormone secretion and glucose levels. A number of GLP-1 receptor agonists (GLP-1RAs) are currently used in treatment of type 2 diabetes and obesity. However, GIP and GLP-1 cognate receptors are widely expressed suggesting that incretin hormones mediate effects beyond control of glucose homeostasis, and reports on associations between incretin hormones and bone metabolism have emerged. The aim of this MiniReview was to provide an overview of current knowledge regarding the in vivo and in vitro effects of GIP and GLP-1 on bone metabolism. We identified a total of 30 pre-clinical and clinical investigations of the effects of GIP, GLP-1 and GLP-1RAs on bone turnover markers, bone mineral density (BMD), bone microarchitecture and fracture risk. Studies conducted in cell cultures and rodents demonstrated that GIP and GLP-1 play a role in regulating skeletal homeostasis, with pre-clinical data suggesting that GIP inhibits bone resorption whereas GLP-1 may promote bone formation and enhance bone material properties. These effects are not corroborated by clinical studies. While there is evidence of effects of GIP and GLP-1 on bone metabolism in pre-clinical investigations, clinical trials are needed to clarify whether similar effects are present and clinically relevant in humans. © 2017 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

  4. cAMP-secretion coupling is impaired in diabetic GK/Par rat β-cells: a defect counteracted by GLP-1.

    Science.gov (United States)

    Dolz, Manuel; Movassat, Jamileh; Bailbé, Danielle; Le Stunff, Hervé; Giroix, Marie-Hélène; Fradet, Magali; Kergoat, Micheline; Portha, Bernard

    2011-11-01

    cAMP-raising agents with glucagon-like peptide-1 (GLP-1) as the first in class, exhibit multiple actions that are beneficial for the treatment of type 2 diabetic (T2D) patients, including improvement of glucose-induced insulin secretion (GIIS). To gain additional insight into the role of cAMP in the disturbed stimulus-secretion coupling within the diabetic β-cell, we examined more thoroughly the relationship between changes in islet cAMP concentration and insulin release in the GK/Par rat model of T2D. Basal cAMP content in GK/Par islets was significantly higher, whereas their basal insulin release was not significantly different from that of Wistar (W) islets. Even in the presence of IBMX or GLP-1, their insulin release did not significantly change despite further enhanced cAMP accumulation in both cases. The high basal cAMP level most likely reflects an increased cAMP generation in GK/Par compared with W islets since 1) forskolin dose-dependently induced an exaggerated cAMP accumulation; 2) adenylyl cyclase (AC)2, AC3, and G(s)α proteins were overexpressed; 3) IBMX-activated cAMP accumulation was less efficient and PDE-3B and PDE-1C mRNA were decreased. Moreover, the GK/Par insulin release apparatus appears less sensitive to cAMP, since GK/Par islets released less insulin at submaximal cAMP levels and required five times more cAMP to reach a maximal secretion rate no longer different from W. GLP-1 was able to reactivate GK/Par insulin secretion so that GIIS became indistinguishable from that of W. The exaggerated cAMP production is instrumental, since GLP-1-induced GIIS reactivation was lost in the presence the AC blocker 2',5'-dideoxyadenosine. This GLP-1 effect takes place in the absence of any improvement of the [Ca(2+)](i) response and correlates with activation of the cAMP-dependent PKA-dependent pathway.

  5. Gαs regulates Glucagon-Like Peptide 1 Receptor-mediated cyclic AMP generation at Rab5 endosomal compartment

    Directory of Open Access Journals (Sweden)

    Shravan Babu Girada

    2017-10-01

    Conclusions: The findings provide the mechanism of endosomal cyclic AMP generation following GLP-1R activation. We identified the specific compartment that serves as an organizing center to generate endosomal cyclic AMP by internalized activated receptor complex.

  6. Refinement of glucagon-like peptide 1 docking to its intact receptor using mid-region photolabile probes and molecular modeling.

    Science.gov (United States)

    Miller, Laurence J; Chen, Quan; Lam, Polo C-H; Pinon, Delia I; Sexton, Patrick M; Abagyan, Ruben; Dong, Maoqing

    2011-05-06

    The glucagon-like peptide 1 (GLP1) receptor is an important drug target within the B family of G protein-coupled receptors. Its natural agonist ligand, GLP1, has incretin-like actions and the receptor is a recognized target for management of type 2 diabetes mellitus. Despite recent solution of the structure of the amino terminus of the GLP1 receptor and several close family members, the molecular basis for GLP1 binding to and activation of the intact receptor remains unclear. We previously demonstrated molecular approximations between amino- and carboxyl-terminal residues of GLP1 and its receptor. In this work, we study spatial approximations with the mid-region of this peptide to gain insights into the orientation of the intact receptor and the ligand-receptor complex. We have prepared two new photolabile probes incorporating a p-benzoyl-l-phenylalanine into positions 16 and 20 of GLP1(7-36). Both probes bound to the GLP1 receptor specifically and with high affinity. These were each fully efficacious agonists, stimulating cAMP accumulation in receptor-bearing CHO cells in a concentration-dependent manner. Each probe specifically labeled a single receptor site. Protease cleavage and radiochemical sequencing identified receptor residue Leu(141) above transmembrane segment one as its site of labeling for the position 16 probe, whereas the position 20 probe labeled receptor residue Trp(297) within the second extracellular loop. Establishing ligand residue approximation with this loop region is unique among family members and may help to orient the receptor amino-terminal domain relative to its helical bundle region.

  7. Homozygous carriers of the G allele of rs4664447 of the glucagon gene (GCG) are characterised by decreased fasting and stimulated levels of insulin, glucagon and glucagon-like peptide (GLP)-1

    DEFF Research Database (Denmark)

    Torekov, S S; Ma, L; Grarup, N

    2011-01-01

    The glucagon gene (GCG) encodes several hormones important for energy metabolism: glucagon, oxyntomodulin and glucagon-like peptide (GLP)-1 and -2. Variants in GCG may associate with type 2 diabetes, obesity and/or related metabolic traits.......The glucagon gene (GCG) encodes several hormones important for energy metabolism: glucagon, oxyntomodulin and glucagon-like peptide (GLP)-1 and -2. Variants in GCG may associate with type 2 diabetes, obesity and/or related metabolic traits....

  8. Design of Glucagon-Like Peptide-1 Receptor Agonist for Diabetes Mellitus from Traditional Chinese Medicine

    Directory of Open Access Journals (Sweden)

    Hsin-Chieh Tang

    2014-01-01

    Full Text Available Glucagon-like peptide-1 (GLP-1 is a promising target for diabetes mellitus (DM therapy and reduces the occurrence of diabetes due to obesity. However, GLP-1 will be hydrolyzed soon by the enzyme dipeptidyl peptidase-4 (DPP-4. We tried to design small molecular drugs for GLP-1 receptor agonist from the world's largest traditional Chinese medicine (TCM Database@Taiwan. According to docking results of virtual screening, we selected 2 TCM compounds, wenyujinoside and 28-deglucosylchikusetsusaponin IV, for further molecular dynamics (MD simulation. GLP-1 was assigned as the control compound. Based on the results of root mean square deviation (RMSD, solvent accessible surface (SAS, mean square deviation (MSD, Gyrate, total energy, root mean square fluctuation (RMSF, matrices of smallest distance of residues, database of secondary structure assignment (DSSP, cluster analysis, and distance of H-bond, we concluded that all the 3 compounds could bind and activate GLP-1 receptor by computational simulation. Wenyujinoside and 28-deglucosylchikusetsusaponin IV were the TCM compounds that could be GLP-1 receptor agonists.

  9. Pancreas and liver uptake of new radiolabeled incretins (GLP-1 and Exendin-4) in models of diet-induced and diet-restricted obesity

    International Nuclear Information System (INIS)

    Seo, Daniele; Faintuch, Bluma Linkowski; Aparecida de Oliveira, Erica; Faintuch, Joel

    2017-01-01

    Introduction: Radiolabeled GLP-1 and its analog Exendin-4, have been employed in diabetes and insulinoma. No protocol in conventional Diet-Induced Obesity (DIO), and Diet-Restricted Obesity (DRO), has been identified. Aiming to assess pancreatic beta cell uptake in DIO and DRO, a protocol was designed. Methods: GLP-1-βAla-HYNIC and HYNIC-βAla-Exendin-4 were labeled with technetium-99m. Four Swiss mouse models were adopted: Controls (C), Alloxan Diabetes Controls (ADC), DIO and DRO. Biodistribution and ex-vivo planar imaging were documented. Results: Radiolabeling yield was in the range of 97% and both agents were hydrophilic. Fasting Blood Glucose (FBG) was 79.2 ± 8.2 mg/dl in C, 590.4 ± 23.3 mg/dl in ADC, 234.3 ± 66.7 mg/dl in DIO, and 96.6 ± 9.3 in DRO (p = 0.010). Biodistribution confirmed predominantly urinary excretion. DIO mice exhibited depressed uptake in liver and pancreas, for both radiomarkers, in the range of ADC. DRO only partially restored such values. 99m Tc-HYNIC-βAla-Exendin-4 demonstrated better results than GLP-1-βAla-HYNIC- 99m Tc. Conclusions: 1) Diet-induced obesity remarkably depressed beta cell uptake; 2) Restriction of obesity failed to normalize uptake, despite robust improvement of FBG; 3) HYNIC-βAla-Exendin-4 was the most useful marker; 4) Further studies are recommended in obesity and dieting, including bariatric surgery.

  10. Anorexigenic postprandial responses of PYY and GLP1 to slow ice cream consumption: preservation in obese adolescents, but not in obese adults.

    Science.gov (United States)

    Rigamonti, A E; Agosti, F; Compri, E; Giunta, M; Marazzi, N; Muller, E E; Cella, S G; Sartorio, A

    2013-03-01

    Eating slowly increases the postprandial responses of some anorexigenic gut hormones in healthy lean subjects. As the rate of food intake is positively associated with obesity, the aim of the study was to determine whether eating the same meal at different rates evokes different postprandial anorexigenic responses in obese adolescent and adult subjects. Eighteen obese adolescents and adults were enrolled. A test meal was consumed on two different sessions by each subject, meal duration taking either 5  min (fast feeding) or 30  min (slow feeding). Circulating levels of glucagon-like peptide 1 (GLP1), peptide YY (PYY), glucose, insulin, and triglycerides were measured over 210  min. Visual analog scales were used to evaluate the subjective feelings of hunger and satiety. fast feeding did not stimulate GLP1 release in obese adolescent and adults, whereas slow feeding increased circulating levels of GLP1 only in obese adolescents. Plasma PYY concentrations increased both in obese adolescents and in adults, irrespective of the eating rate, but slow feeding was more effective in stimulating PYY release in obese adolescents than in adults. simultaneously, slow feeding evoked a higher satiety only in obese adolescents compared with fast feeding but not in obese adults. in obese adolescents, slow feeding decreased hunger (only at 210 min). irrespective of the eating rate, postprandial responses of insulin and triglycerides were higher in obese adults than in obese adolescents. Slow feeding leads to higher concentrations of anorexigenic gut peptides and favors satiety in obese adolescents, but this physiological control of food intake is lost in obese adults.

  11. Glucagon-like peptide-1 receptor agonists in the treatment of type 2 diabetes: Past, present, and future

    Directory of Open Access Journals (Sweden)

    Sanjay Kalra

    2016-01-01

    Full Text Available Glucagon-like peptide-1 (GLP-1–based therapy improves glycaemic control through multiple mechanisms, with a low risk of hypoglycaemia and the additional benefit of clinically relevant weight loss. Since Starling and Bayliss first proposed the existence of intestinal secretions that stimulate the pancreas, tremendous progress has been made in the area of incretins. As a number of GLP-1 receptor agonists (GLP-1 RAs continue to become available, physicians will soon face the challenge of selecting the right option customized to their patient's needs. The following discussion, derived from an extensive literature search using the PubMed database, applying the terms incretin, GLP-1, exenatide, liraglutide, albiglutide, dulaglutide, lixisenatide, semaglutide, and taspoglutide, provides a comprehensive review of existing and upcoming molecules in the GLP-1 RA class in terms of their structure, pharmacological profiles, efficacy, safety, and convenience. Search Methodology: A literature search was conducted using the PubMed database, applying the terms incretin, GLP-1, exenatide, liraglutide, albiglutide, dulaglutide, lixisenatide, semaglutide, and taspoglutide. Relevant articles were those that discussed structural, pharmacokinetic and pharmacodynamic differences, classification, long-acting and short-acting GLP-1 RAs, phase 3 trials, and expert opinions. Additional targeted searches were conducted on diabetes treatment guidelines and reviews on safety, as well as the American Diabetes Association/European Society for Study of Diabetes (ADA/EASD statement on pancreatic safety.

  12. Novel GLP-1 Analog Supaglutide Reduces HFD-Induced Obesity Associated with Increased Ucp-1 in White Adipose Tissue in Mice

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    Yun Wan

    2017-05-01

    Full Text Available GLP-1, an important incretin hormone plays an important role in the regulation of glucose homeostasis. However, the therapeutic use of native GLP-1 is limited due to its short half-life. We recently developed a novel GLP-1 mimetics (supaglutide by genetically engineering recombinant fusion protein production techniques. We demonstrated that this formulation possessed long-lasting GLP-1 actions and was effective in glycemic control in both type 1 and type 2 diabetes rodent models. Here, we investigated the effects of supaglutide in regulating energy homeostasis in obese mice. Mice were fed with high-fat diet (HFD for 6 months to induce obesity and then subjected to supaglutide treatment (300 μg/kg, bi-weekly for 4 weeks, and placebo as control. Metabolic conditions were monitored and energy expenditure was assessed by indirect calorimetry (CLAMS. Cold tolerance test was performed to evaluate brown-adipose tissue (BAT activities in response to cold challenge. Glucose tolerance and insulin resistance were evaluated by intraperitoneal glucose tolerance test and insulin tolerance tests. Liver and adipose tissues were collected for histology analysis. Expression of uncoupling protein 1(Ucp1 in adipose tissues was evaluated by Western blotting. We found that supaglutide treatment reduced body weight, which was associated with reduced food intake. Compared to the placebo control, supaglutide treatment improved lipid profile, i.e., significantly decreased circulating total cholesterol levels, declined serum triglyceride, and free fatty acid levels. Importantly, the intervention significantly reduced fatty liver, decreased liver triglyceride content, and concomitantly ameliorated liver injury exemplified by declined hepatic alanine aminotransferase (ALT and aspartic transaminase (AST content. Remarkably, supaglutide reduced hepatic lipid accumulation and altered morphometry in favor of small adipocytes in fat. This is consistent with the observation that

  13. The 2-monoacylglycerol moiety of dietary fat appears to be responsible for the fat-induced release of GLP-1 in humans

    DEFF Research Database (Denmark)

    Mandøe, Mette J.; Hansen, Katrine B.; Hartmann, Bolette

    2015-01-01

    acid), olive oil [contg. long-chain fatty acids; e.g., oleic acid plus 2-oleoyl glycerol (2-OG)], and 1,3-dioctanoyl-2-oleoyl glycerol (C8-dietary oil), which is digested to form medium-chain fatty acids (i.e., octanoic acid) and 2-OG. Design: In a randomized, single-blinded crossover study, 12 healthy...... white men [mean age: 24 y; BMI (in kg/m2): 22] were given the following 4 meals on 4 different days: 200 g carrots + 6.53 g tributyrin, 200 g carrots + 13.15 g C8-dietary oil, 200 g carrots + 19 g olive oil, or 200 g carrots. All of the lipids totaled 0.0216 mol. Main outcome measures were incremental...... areas under the curve for total GLP-1, GIP, and cholecystokinin (CCK) in plasma. Results: C8-dietary oil and olive oil showed the same GLP-1 response [583 ± 101 and 538 ± 71 (pmol/L) × 120 min; P = 0.733], whereas the GIP response was higher for olive oil than for C8-dietary oil [3293 ± 404 and 1674...

  14. Failure of sucrose replacement with the non-nutritive sweetener erythritol to alter GLP-1 or PYY release or test meal size in lean or obese people.

    Science.gov (United States)

    Overduin, Joost; Collet, Tinh-Hai; Medic, Nenad; Henning, Elana; Keogh, Julia M; Forsyth, Faye; Stephenson, Cheryl; Kanning, Marja W; Ruijschop, Rianne M A J; Farooqi, I Sadaf; van der Klaauw, Agatha A

    2016-12-01

    There is considerable interest in the effect of foods containing high intensity sweeteners on satiation. However, less is known about low-calorie bulk sweeteners such as erythritol. In this randomized three-way crossover study, we studied 10 lean and 10 obese volunteers who consumed three test meals on separate occasions: (a) control sucrose meal; (b) isovolumic meal with partial replacement of sucrose by erythritol; (c) isocaloric meal which contained more erythritol but equivalent calories to the control meal. We measured gut hormone levels, hunger and satiety scores, ad libitum food intake, sucrose preference and intake after the manipulations. There was a greater post-prandial excursion in glucose and insulin levels after sucrose than after the erythritol meals. There was no difference in GLP-1/PYY levels or subsequent energy intake and sucrose preference between sucrose control and isovolumic erythritol meals. In lean (but not obese) participants, hunger decreased to a greater extent after the isocaloric erythritol meal compared to the control meal (p = 0.003) reflecting the larger volume of this meal. Replacing sucrose with erythritol leads to comparable hunger and satiety scores, GLP-1 and PYY levels, and subsequent sucrose preference and intake. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. The GLP-1 Analogue Exenatide Improves Hepatic and Muscle Insulin Sensitivity in Diabetic Rats: Tracer Studies in the Basal State and during Hyperinsulinemic-Euglycemic Clamp

    Directory of Open Access Journals (Sweden)

    Hui Wu

    2014-01-01

    Full Text Available Objective. Glucagon-like peptide-1 (GLP-1 analogues (e.g., exenatide increase insulin secretion in diabetes but less is known about their effects on glucose production or insulin-stimulated glucose uptake in peripheral tissues. Methods. Four groups of Sprague-Dawley rats were studied: nondiabetic (control, C; nondiabetic + exenatide (C + E; diabetic (D; diabetic + exenatide (D + E with diabetes induced by streptozotocin and high fat diet. Infusion of 3-3H-glucose and U-13C-glycerol was used to measure basal rates of appearance (Ra of glucose and glycerol and gluconeogenesis from glycerol (GNG. During hyperinsulinemic-euglycemic clamp, glucose uptake into gastrocnemius muscles was measured with 2-deoxy-D-14C-glucose. Results. In the diabetic rats, exenatide reduced the basal Ra of glucose (P<0.01 and glycerol (P<0.01 and GNG (P<0.001. During the clamp, Ra of glucose was also reduced, whereas the rate of disappearance of glucose increased and there was increased glucose uptake into muscle (P<0.01 during the clamp. In the nondiabetic rats, exenatide had no effect. Conclusion. In addition to its known effects on insulin secretion, administration of the GLP-1 analogue, exenatide, is associated with increased inhibition of gluconeogenesis and improved glucose uptake into muscle in diabetic rats, implying improved hepatic and peripheral insulin sensitivity.

  16. Difference in postprandial GLP-1 response despite similar glucose kinetics after consumption of wheat breads with different particle size in healthy men.

    Science.gov (United States)

    Eelderink, Coby; Noort, Martijn W J; Sozer, Nesli; Koehorst, Martijn; Holst, Jens J; Deacon, Carolyn F; Rehfeld, Jens F; Poutanen, Kaisa; Vonk, Roel J; Oudhuis, Lizette; Priebe, Marion G

    2017-04-01

    Underlying mechanisms of the beneficial health effects of low glycemic index starchy foods are not fully elucidated yet. We varied the wheat particle size to obtain fiber-rich breads with a high and low glycemic response and investigated the differences in postprandial glucose kinetics and metabolic response after their consumption. Ten healthy male volunteers participated in a randomized, crossover study, consuming 13 C-enriched breads with different structures; a control bread (CB) made from wheat flour combined with wheat bran, and a kernel bread (KB) where 85 % of flour was substituted with broken wheat kernels. The structure of the breads was characterized extensively. The use of stable isotopes enabled calculation of glucose kinetics: rate of appearance of exogenous glucose, endogenous glucose production, and glucose clearance rate. Additionally, postprandial plasma concentrations of glucose, insulin, glucagon, incretins, cholecystokinin, and bile acids were analyzed. Despite the attempt to obtain a bread with a low glycemic response by replacing flour by broken kernels, the glycemic response and glucose kinetics were quite similar after consumption of CB and KB. Interestingly, the glucagon-like peptide-1 (GLP-1) response was much lower after KB compared to CB (iAUC, P bread did not result in a difference in glucose response and kinetics, but in a pronounced difference in GLP-1 response. Thus, changing the processing conditions of wheat for baking bread can influence the metabolic response beyond glycemia and may therefore influence health.

  17. Purification of family B G protein-coupled receptors using nanodiscs: Application to human glucagon-like peptide-1 receptor.

    Directory of Open Access Journals (Sweden)

    Yingying Cai

    Full Text Available Family B G protein-coupled receptors (GPCRs play vital roles in hormone-regulated homeostasis. They are drug targets for metabolic diseases, including type 2 diabetes and osteoporosis. Despite their importance, the signaling mechanisms for family B GPCRs at the molecular level remain largely unexplored due to the challenges in purification of functional receptors in sufficient amount for biophysical characterization. Here, we purified the family B GPCR human glucagon-like peptide-1 (GLP-1 receptor (GLP1R, whose agonists, e.g. exendin-4, are used for the treatment of type 2 diabetes mellitus. The receptor was expressed in HEK293S GnTl- cells using our recently developed protocol. The protocol incorporates the receptor into the native-like lipid environment of reconstituted high density lipoprotein (rHDL particles, also known as nanodiscs, immediately after the membrane solubilization step followed by chromatographic purification, minimizing detergent contact with the target receptor to reduce denaturation and prolonging stabilization of receptor in lipid bilayers without extra steps of reconstitution. This method yielded purified GLP1R in nanodiscs that could bind to GLP-1 and exendin-4 and activate Gs protein. This nanodisc purification method can potentially be a general strategy to routinely obtain purified family B GPCRs in the 10s of microgram amounts useful for spectroscopic analysis of receptor functions and activation mechanisms.

  18. Purification of family B G protein-coupled receptors using nanodiscs: Application to human glucagon-like peptide-1 receptor.

    Science.gov (United States)

    Cai, Yingying; Liu, Yuting; Culhane, Kelly J; DeVree, Brian T; Yang, Yang; Sunahara, Roger K; Yan, Elsa C Y

    2017-01-01

    Family B G protein-coupled receptors (GPCRs) play vital roles in hormone-regulated homeostasis. They are drug targets for metabolic diseases, including type 2 diabetes and osteoporosis. Despite their importance, the signaling mechanisms for family B GPCRs at the molecular level remain largely unexplored due to the challenges in purification of functional receptors in sufficient amount for biophysical characterization. Here, we purified the family B GPCR human glucagon-like peptide-1 (GLP-1) receptor (GLP1R), whose agonists, e.g. exendin-4, are used for the treatment of type 2 diabetes mellitus. The receptor was expressed in HEK293S GnTl- cells using our recently developed protocol. The protocol incorporates the receptor into the native-like lipid environment of reconstituted high density lipoprotein (rHDL) particles, also known as nanodiscs, immediately after the membrane solubilization step followed by chromatographic purification, minimizing detergent contact with the target receptor to reduce denaturation and prolonging stabilization of receptor in lipid bilayers without extra steps of reconstitution. This method yielded purified GLP1R in nanodiscs that could bind to GLP-1 and exendin-4 and activate Gs protein. This nanodisc purification method can potentially be a general strategy to routinely obtain purified family B GPCRs in the 10s of microgram amounts useful for spectroscopic analysis of receptor functions and activation mechanisms.

  19. Body weight loss, reduced urge for palatable food and increased release of GLP-1 through daily supplementation with green-plant membranes for three months in overweight women.

    Science.gov (United States)

    Montelius, Caroline; Erlandsson, Daniel; Vitija, Egzona; Stenblom, Eva-Lena; Egecioglu, Emil; Erlanson-Albertsson, Charlotte

    2014-10-01

    The frequency of obesity has risen dramatically in recent years but only few effective and safe drugs are available. We investigated if green-plant membranes, previously shown to reduce subjective hunger and promote satiety signals, could affect body weight when given long-term. 38 women (40-65 years of age, body mass index 25-33 kg/m(2)) were randomized to dietary supplementation with either green-plant membranes (5 g) or placebo, consumed once daily before breakfast for 12 weeks. All individuals were instructed to follow a three-meal paradigm without any snacking between the meals and to increase their physical activity. Body weight change was analysed every third week as was blood glucose and various lipid parameters. On days 1 and 90, following intake of a standardized breakfast, glucose, insulin and glucagon-like peptide 1 (GLP-1) in plasma were measured, as well as subjective ratings of hunger, satiety and urge for different palatable foods, using visual analogue scales. Subjects receiving green-plant membranes lost significantly more body weight than did those on placebo (p weight loss with green-plant extract was 5.0 ± 2.3 kg compared to 3.5 ± 2.3 kg in the control group. Consumption of green-plant membranes also reduced total and LDL-cholesterol (p meal tests performed on day 1 and day 90 demonstrated an increased postprandial release of GLP-1 and decreased urge for sweet and chocolate on both occasions in individuals supplemented with green-plant membranes compared to control. Waist circumference, body fat and leptin decreased in both groups over the course of the study, however there were no differences between the groups. In conclusion, addition of green-plant membranes as a dietary supplement once daily induces weight loss, improves obesity-related risk-factors, and reduces the urge for palatable food. The mechanism may reside in the observed increased release of GLP-1. Copyright © 2014 The Authors. Published by Elsevier Ltd

  20. The impact of short chain fatty acids on GLP-1 and PYY secretion from the isolated perfused rat colon

    DEFF Research Database (Denmark)

    Christiansen, Charlotte Bayer; Gabe, Maria Buur Nordskov; Svendsen, Berit

    2018-01-01

    chain fatty acids (SCFAs) produced by local bacterial fermentation are suggested to activate the colonic free fatty acid receptors FFAR2 (GPR43) and FFAR3 (GPR41), stimulating the colonic L-cells. We used the isolated perfused rat colon as a model of colonic endocrine secretion and studied the effects...

  1. Difference in postprandial GLP-1 response despite similar glucose kinetics after consumption of wheat breads with different particle size in healthy men

    DEFF Research Database (Denmark)

    Eelderink, Coby; Noort, Martijn W J; Sozer, Nesli

    2017-01-01

    PURPOSE: Underlying mechanisms of the beneficial health effects of low glycemic index starchy foods are not fully elucidated yet. We varied the wheat particle size to obtain fiber-rich breads with a high and low glycemic response and investigated the differences in postprandial glucose kinetics...... and metabolic response after their consumption. METHODS: Ten healthy male volunteers participated in a randomized, crossover study, consuming (13)C-enriched breads with different structures; a control bread (CB) made from wheat flour combined with wheat bran, and a kernel bread (KB) where 85 % of flour...... in a difference in glucose response and kinetics, but in a pronounced difference in GLP-1 response. Thus, changing the processing conditions of wheat for baking bread can influence the metabolic response beyond glycemia and may therefore influence health....

  2. Treatment with a GLP-1R agonist over four weeks promotes weight loss-moderated changes in frontal-striatal brain structures in individuals with mood disorders

    DEFF Research Database (Denmark)

    Mansur, Rodrigo B; Zugman, Andre; Ahmed, Juhie

    2017-01-01

    regions (e.g. RR: 1.011, p=0.049 in the left rostral middle frontal area). Changes in regional volumes were associated with improvement in executive function (e.g. r=0.698, p=0.003 for the right superior frontal area). Adjunctive liraglutide results in clinically significant weight loss......, with corresponding improvement in cognitive function; changes in cognitive function were partially moderated by changes in brain morphometry, underscoring the interrelationship between weight and brain structure/function.......Cognitive deficits are a core feature across psychiatric disorders. Emerging evidence indicates that metabolic pathways are highly relevant for the substrates and phenomenology of the cognitive domain. Herein, we aimed to determine the effects of liraglutide, a GLP-1R agonist, on brain structural...

  3. Postprandial diabetic glucose tolerance is normalized by gastric bypass feeding as opposed to gastric feeding and is associated with exaggerated GLP-1 secretion: a case report

    DEFF Research Database (Denmark)

    Dirksen, Carsten; Hansen, Dorte L; Madsbad, Sten

    2010-01-01

    into the bypassed gastric remnant and on the second day perorally. Plasma glucose, insulin, C-peptide, glucagon, incretin hormones, peptide YY, and free fatty acids were measured. RESULTS: Peroral feeding reduced 2-h postprandial plasma glucose (7.8 vs. 11.1 mmol/l) and incremental area under the glucose curve (iAUC......) (0.33 vs. 0.49 mmol . l(-1) . min(-1)) compared with gastroduodenal feeding. beta-Cell function (iAUC(Cpeptide/Glu)) was more than twofold improved during peroral feeding, and the glucagon-like peptide (GLP)-1 response increased nearly fivefold. CONCLUSIONS: Improvement in postprandial glucose......OBJECTIVE: To examine after gastric bypass the effect of peroral versus gastroduodenal feeding on glucose metabolism. RESEARCH DESIGN AND METHODS: A type 2 diabetic patient was examined on 2 consecutive days 5 weeks after gastric bypass. A standard liquid meal was given on the first day...

  4. Pancreatic Polypeptide Cell Proliferation in the Pancreas and Duodenum Coexisting in a Patient With Pancreatic Adenocarcinoma Treated With a GLP-1 Analog.

    Science.gov (United States)

    Talmon, Geoffrey A; Wren, J David; Nguyen, Christophe L; Pour, Parviz M

    2017-07-01

    A partial pancreaticogastrodudenectomy was performed on a 66-year old man with type 2 diabetes mellitus because of an invasive, moderately differentiated adenocarcinoma in the head of the pancreas. In the adjacent grossly normal tissue of the uncinate process, there was a massive proliferation of pancreatic polypeptide (PP) cells confined to this region and showed invasive pattern. Strikingly, in the heaped area of his duodenum, there was a strikingly large number of PP, glucagon, a few insulin cells in a mini-islet-like patterns composed of glucagon and insulin cells. Among the etiological factors, the possible long-lasting effects of the GLP-1 analog, with which the patient was treated, are discussed. This is the first report in the literature of both the coexistence of a pancreatic adenocarcinoma and invasive PPoma and the occurrence of PP and insulin cells in human duodenal mucosa.

  5. Effect of Age on Blood Glucose and Plasma Insulin, Glucagon, Ghrelin, CCK, GIP, and GLP-1 Responses to Whey Protein Ingestion

    Directory of Open Access Journals (Sweden)

    Caroline Giezenaar

    2017-12-01

    Full Text Available Protein-rich supplements are used widely to prevent and manage undernutrition in older people. We have previously shown that healthy older, compared to younger, adults have less suppression of energy intake by whey protein—although the effects of age on appetite-related gut hormones are largely unknown. The aim of this study was to determine and compare the acute effects of whey protein loads on blood glucose and plasma gut hormone concentrations in older and younger adults. Sixteen healthy older (eight men, eight women; mean ± SEM: age: 72 ± 1 years; body mass index: 25 ± 1 kg/m2 and 16 younger (eight men, eight women; 24 ± 1 years; 23 ± 0.4 kg/m2 adults were studied on three occasions in which they ingested 30 g (120 kcal or 70 g (280 kcal whey protein, or a flavored-water control drink (~2 kcal. At regular intervals over 180 min, blood glucose and plasma insulin, glucagon, ghrelin, cholecystokinin (CCK, gastric inhibitory peptide (GIP, and glucagon-like peptide-1 (GLP-1 concentrations were measured. Plasma ghrelin was dose-dependently suppressed and insulin, glucagon, CCK, GIP, and GLP-1 concentrations were dose-dependently increased by the whey protein ingestion, while blood glucose concentrations were comparable during all study days. The stimulation of plasma CCK and GIP concentrations was greater in older than younger adults. In conclusion, orally ingested whey protein resulted in load-dependent gut hormone responses, which were greater for plasma CCK and GIP in older compared to younger adults.

  6. HOMA-S is associated with greater HbA1c reduction with a GLP-1 analogue in patients with type 2 diabetes.

    Science.gov (United States)

    Heald, A H; Narayanan, R P; Lowes, D; Jarman, E; Onyekwelu, E; Qureshi, Z; Laing, I; Anderson, S G

    2012-07-01

    Exenatide, a glucagon-like peptide-1 (GLP-1) analogue, is an effective glucoregulator for treating overweight individuals, not at target HbA1 c. This prospective study aimed to determine whether estimates of beta cell function (HOMA-B) and insulin sensitivity (HOMA-S) predict response to Exenatide treatment.Prospective data on 43 type 2 diabetes patients were collected for up to 2.8 years in UK primary care. HOMA-B and HOMA-S were estimated prior to initiating Exenatide, with monitoring of cardio-metabolic risk factors.Mean (SD) age and BMI pre-treatment were 54.1±10.5 years and 35.7±7.5 kg/m2 respectively. HbA1c decreased (mean reduction 0.9%, p=0.04; p for trend=0.01) in 61% of patients. In univariate analyses, HOMA-S as a measure of insulin sensitivity was inversely (β=- 0.41, p 0.009) related to change in HbA1c, with no relation for HOMA-B.In a random effects regression model that included age at baseline, weight, LDL-C, HDL-C and triglycerides, change in HbA1c (β= - 0.14, pHOMA-S were 45% more likely to have a fall in HbA1c with an odds ratio (OR) of 0.55 (95% CI 0.47-0.66) p<0.0001 (log likelihood ratio for the model χ2=71.6, p<0.0001).Patients with greater measured insulin sensitivity achieve greater reduction in HbA1c with Exenatide. Determination of insulin sensitivity may assist in guiding outcome expectation in overweight patients treated with GLP-1 analogues. © J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York.

  7. GLP-1 Elicits an Intrinsic Gut-Liver Metabolic Signal to Ameliorate Diet-Induced VLDL Overproduction and Insulin Resistance.

    Science.gov (United States)

    Khound, Rituraj; Taher, Jennifer; Baker, Christopher; Adeli, Khosrow; Su, Qiaozhu

    2017-12-01

    Perturbations in hepatic lipid and very-low-density lipoprotein (VLDL) metabolism are involved in the pathogenesis of obesity and hepatic insulin resistance. The objective of this study is to delineate the mechanism of subdiaphragmatic vagotomy in preventing obesity, hyperlipidemia, and insulin resistance. By subjecting the complete subdiaphragmatic vagotomized mice to various nutritional conditions and investigating hepatic de novo lipogenesis pathway, we found that complete disruption of subdiaphragmatic vagal signaling resulted in a significant decrease of circulating VLDL-triglyceride compared with the mice obtained sham procedure. Vagotomy further prevented overproduction of VLDL-triglyceride induced by an acute fat load and a high-fat diet-induced obesity, hyperlipidemia, hepatic steatosis, and glucose intolerance. Mechanistic studies revealed that plasma glucagon-like peptide-1 was significantly raised in the vagotomized mice, which was associated with significant reductions in mRNA and protein expression of SREBP-1c (sterol regulatory element-binding protein 1c), SCD-1 (stearoyl-CoA desaturase-1), and FASN (fatty acid synthase), as well as enhanced hepatic insulin sensitivity. In vitro, treating mouse primary hepatocytes with a glucagon-like peptide-1 receptor agonist, exendin-4, for 48 hours inhibited free fatty acid, palmitic acid treatment induced de novo lipid synthesis, and VLDL secretion from hepatocytes. Elevation of glucagon-like peptide-1 in vagotomized mice may prevent VLDL overproduction and insulin resistance induced by high-fat diet. These novel findings, for the first time, delineate an intrinsic gut-liver regulatory circuit that is mediated by glucagon-like peptide-1 in regulating hepatic energy metabolism. © 2017 American Heart Association, Inc.

  8. Secretion of incretin hormones (GIP and GLP-1) and incretin effect after oral glucose in first-degree relatives of patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Nauck, Michael A; El-Ouaghlidi, Andrea; Gabrys, Bartholomäus

    2004-01-01

    ) and an "isoglycaemic" intravenous glucose infusion. Blood was drawn over 240 min for plasma glucose (glucose oxidase), insulin, C-peptide, GIP and glucagon-like peptide 1 (GLP-1; specific immunoassays). RESULTS: The pattern of glucose concentrations could precisely be copied by the intravenous glucose infusion (p=0......AIMS/HYPOTHESIS: Since insulin secretion in response to exogenous gastric inhibitory polypeptide (GIP) is diminished not only in patients with type 2 diabetes, but also in their normal glucose-tolerant first-degree relatives, it was the aim to investigate the integrity of the entero-insular axis...... in such subjects. METHODS: Sixteen first-degree relatives of patients with type 2 diabetes (4 male, 12 female, age 50+/-12 years, BMI 26.1+/-3.8 kg/m(2)) and 10 matched healthy controls (negative family history, 6 male, 4 female, 45+/-13 years, 26.1+/-4.2 kg/m(2)) were examined with an oral glucose load (75 g...

  9. Integrative function of adrenaline receptors for glucagon-like peptide-1 exocytosis in enteroendocrine L cell line GLUTag.

    Science.gov (United States)

    Harada, Kazuki; Kitaguchi, Tetsuya; Tsuboi, Takashi

    2015-05-15

    Adrenaline reacts with three types of adrenergic receptors, α1, α2 and β-adrenergic receptors (ARs), inducing many physiological events including exocytosis. Although adrenaline has been shown to induce glucagon-like peptide-1 (GLP-1) secretion from intestinal L cells, the precise molecular mechanism by which adrenaline regulates GLP-1 secretion remains unknown. Here we show by live cell imaging that all types of adrenergic receptors are stimulated by adrenaline in enteroendocrine L cell line GLUTag cells and are involved in GLP-1 exocytosis. We performed RT-PCR analysis and found that α1B-, α2A-, α2B-, and β1-ARs were expressed in GLUTag cells. Application of adrenaline induced a significant increase of intracellular Ca(2+) and cAMP concentration ([Ca(2+)]i and [cAMP]i, respectively), and GLP-1 exocytosis in GLUTag cells. Blockade of α1-AR inhibited adrenaline-induced [Ca(2+)]i increase and exocytosis but not [cAMP]i increase, while blockade of β1-AR inhibited adrenaline-induced [cAMP]i increase and exocytosis but not [Ca(2+)]i increase. Furthermore, overexpression of α2A-AR suppressed the adrenaline-induced [cAMP]i increase and exocytosis. These results suggest that the fine-turning of GLP-1 secretion from enteroendocrine L cells is established by the balance between α1-, α2-, and β-ARs activation. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Effect of rs6923761 gene variant of glucagon-like peptide 1 receptor on metabolic response and weight loss after a 3-month intervention with a hypocaloric diet.

    Science.gov (United States)

    de Luis, Daniel Antonio; Aller, Rocío; Izaola, Olatz; Lopez, J J; Gomez, E; Torres, B; Soto, G Diaz

    2014-10-01

    Studies of the GLP-1 receptor (GLP-1 R) have been directed at identifying polymorphisms in the GLP-1 R gene that may be a contributing factor in the pathogenesis of obesity and cardiovascular risk factors. Nevertheless, the role of GLP-1 R variants on body weight response after dietary intervention has not been evaluated. We decided to analyze the effects of the rs6923761 GLP-1 R polymorphism on body weight changes and metabolic parameters after 3 months of a hypocaloric diet. A sample of 91 obese subjects was analyzed in a prospective way. The hypocaloric diet had 1,520 calories per day; 52 % of carbohydrates, 25 % of lipids and 23 % of proteins. Distribution of fats was: 50.7 % of monounsaturated fats, 38.5 % of saturated fats and 11.8 % of polyunsaturated fats. In both genotype groups (GG vs. GA + AA), weight, body mass index, fat mass, waist circumference, systolic blood pressure, total cholesterol, LDL cholesterol, leptin, insulin and HOMA levels decreased. No statistical differences were detected in these changes between genotypes. In wild group (GG genotype) (pretreatment and posttreatment), BMI, weight, fat mass, waist circumference and triglyceride levels were higher than (GA + AA) group. Our data showed better anthropometric parameters and triglyceride levels in obese subjects with the mutant allele (A) of rs6923761 GLP-1R polymorphism. A lack of association of this polymorphism with weight loss or biochemical changes after a hypocaloric diet was observed.

  11. Glucagon-Like Peptide-1 Receptor Agonists for the Treatment of Type 2 Diabetes Mellitus: A Position Statement of the Korean Diabetes Association.

    Science.gov (United States)

    Kim, Hyun Jin; Park, Seok O; Ko, Seung Hyun; Rhee, Sang Youl; Hur, Kyu Yeon; Kim, Nan Hee; Moon, Min Kyong; Lee, Byung Wan; Kim, Jin Hwa; Choi, Kyung Mook

    2017-12-01

    The glucagon-like peptide-1 receptor agonists (GLP-1RAs) were recommended as a monotherapy or combination therapy with oral hypoglycemic agents or basal insulin in the position statement of the Korean Diabetes Association 2017 for pharmacological therapy. Many randomized clinical trials and systematic reviews report that GLP-1RAs have considerable glucose-lowering effect and lead to weight reduction and low risk of hypoglycemia when used as a monotherapy or combination therapy. The cardiovascular safety of GLP-1RAs has been assessed in several randomized clinical trials and systematic reviews. The results of cardiovascular outcome trials of long-acting GLP-1RAs (liraglutide, semaglutide) demonstrated cardiovascular benefits in subjects with type 2 diabetes mellitus and a high risk of cardiovascular disease. The GLP-1RA may be a choice of therapy when weight control and avoidance of hypoglycemia are important, and patients with high risk of cardiovascular disease might also favor choosing GLP-1RA. Copyright © 2017 Korean Diabetes Association.

  12. Optimization of tolerability and efficacy of the novel dual amylin and calcitonin receptor agonist KBP-089 through dose escalation and combination with a GLP-1 analog

    DEFF Research Database (Denmark)

    Gydesen, Sofie; Andreassen, Kim Vietz; Hjuler, Sara Toftegaard

    2017-01-01

    , and the following treatment with 2.5, 10, and 40 µg/kg resulted in an ~15% vehicle-corrected weight loss, a corresponding reduction in adipose tissue (AT), and, in all treatment groups, improved oral glucose tolerance (P weight evenly with no significant...... second day obtained equal weight loss at study end, albeit with an uneven reduction in both food intake and body weight in rats dosed every second day. In a 4-fold dose escalation, KBP-089 induced a transient reduction in food intake at every escalation step, with reducing magnitude over time...... reduction in food intake at either escalation step. KBP-089 (1.25 µg/kg) and liraglutide (50 µg/kg) reduced 24-h food intake by 29% and 37% compared with vehicle, respectively; however, when they were combined, 24-h food intake was reduced by 87%. Chronically, KBP-089 (1.25 µg/kg) and liraglutide (50 µg...

  13. Lower glucose-dependent insulinotropic polypeptide (GIP) response but similar glucagon-like peptide 1 (GLP-1), glycaemic, and insulinaemic response to ancient wheat compared to modern wheat depends on processing

    DEFF Research Database (Denmark)

    Bakhøj, S; Flint, A.; Holst, Jens Juul

    2003-01-01

    with honey-salt added, leavening crushed whole grain, and conventional leavening with yeast added. Bread made from modern wheat was prepared by conventional leavening with yeast added. SUBJECTS: A total of 11 healthy young men. RESULTS: The postprandial GIP response was significantly (P... by the Einkorn breads processed with honey-salt leavening and by using crushed whole grain bread compared to the yeast leavened bread made from modern wheat or from Einkorn. No significant differences were found in the responses of GLP-1, insulin or glucose. CONCLUSION: Einkorn honey-salt leavened and Einkorn...... whole grain bread elicit a reduced gastrointestinal response of GIP compared to conventional yeast bread. No differences were found in the glycaemic, insulinaemic and GLP-1 responses. Processing of starchy foods such as wheat may be a powerful tool to modify the postprandial GIP response....

  14. Functional Consequences of Glucagon-like Peptide-1 Receptor Cross-talk and Trafficking

    DEFF Research Database (Denmark)

    Roed, Sarah Noerklit; Nøhr, Anne Cathrine; Wismann, Pernille

    2015-01-01

    The signaling capacity of seven-transmembrane/G-protein-coupled receptors (7TM/GPCRs) can be regulated through ligand-mediated receptor trafficking. Classically, the recycling of internalized receptors is associated with resensitization, whereas receptor degradation terminates signaling. We have......) and glucagon (GCGR) receptors. The interaction and cross-talk between coexpressed receptors is a wide phenomenon of the 7TM/GPCR superfamily. Numerous reports show functional consequences for signaling and trafficking of the involved receptors. On the basis of the high structural similarity and tissue...... coexpression, we here investigated the potential cross-talk between GLP-1R and GIPR or GCGR in both trafficking and signaling pathways. Using a real-time time-resolved FRET-based internalization assay, we show that GLP-1R, GIPR, and GCGR internalize with differential properties. Remarkably, upon coexpression...

  15. Preoperative weight loss with glucagon-like peptide-1 receptor agonist treatment predicts greater weight loss achieved by the combination of medical weight management and bariatric surgery in patients with type 2 diabetes: A longitudinal analysis.

    Science.gov (United States)

    Tang, Tien; Abbott, Sally; le Roux, Carel W; Wilson, Violet; Singhal, Rishi; Bellary, Srikanth; Tahrani, Abd A

    2018-03-01

    We examined the relationship between weight changes after preoperative glucagon-like peptide-1 receptor agonist (GLP-1RA) treatment and weight changes from the start of medical weight management (MWM) until 12 months after bariatric surgery in patients with type 2 diabetes in a retrospective cohort study. A total of 45 patients (64.4% women, median [interquartile range] age 49 [45-60] years) were included. The median (interquartile range) weight loss from start of MWM until 12 months post-surgery was 17.9% (13.0%-29.3%). GLP-1RA treatment during MWM resulted in 5.0% (1.9%-7.7%) weight loss. Weight loss during GLP-1RA treatment predicted weight loss from the start of MWM until 12 months post-surgery, but not postoperative weight loss after adjustment. The proportion of weight loss from start of MWM to 12 months post-surgery attributed to GLP-1RA treatment was negatively associated with that attributed to surgery, after adjustment. In conclusion, weight change after GLP-1RA treatment predicted the weight loss achieved by a combination of MWM and bariatric surgery, but not weight loss induced by surgery only. Failure to lose weight after GLP-1RA treatment should not be considered a barrier to undergoing bariatric surgery. © 2017 John Wiley & Sons Ltd.

  16. Gαs regulates Glucagon-Like Peptide 1 Receptor-mediated cyclic AMP generation at Rab5 endosomal compartment.

    Science.gov (United States)

    Girada, Shravan Babu; Kuna, Ramya S; Bele, Shilpak; Zhu, Zhimeng; Chakravarthi, N R; DiMarchi, Richard D; Mitra, Prasenjit

    2017-10-01

    Upon activation, G protein coupled receptors (GPCRs) associate with heterotrimeric G proteins at the plasma membrane to initiate second messenger signaling. Subsequently, the activated receptor experiences desensitization, internalization, and recycling back to the plasma membrane, or it undergoes lysosomal degradation. Recent reports highlight specific cases of persistent cyclic AMP generation by internalized GPCRs, although the functional significance and mechanistic details remain to be defined. Cyclic AMP generation from internalized Glucagon-Like Peptide-1 Receptor (GLP-1R) has previously been reported from our laboratory. This study aimed at deciphering the molecular mechanism by which internalized GLP-R supports sustained cyclic AMP generation upon receptor activation in pancreatic beta cells. We studied the time course of cyclic AMP generation following GLP-1R activation with particular emphasis on defining the location where cyclic AMP is generated. Detection involved a novel GLP-1 conjugate coupled with immunofluorescence using specific endosomal markers. Finally, we employed co-immunoprecipitation as well as immunofluorescence to assess the protein-protein interactions that regulate GLP-1R mediated cyclic AMP generation at endosomes. Our data reveal that prolonged association of G protein α subunit Gαs with activated GLP-1R contributed to sustained cyclic AMP generation at Rab 5 endosomal compartment. The findings provide the mechanism of endosomal cyclic AMP generation following GLP-1R activation. We identified the specific compartment that serves as an organizing center to generate endosomal cyclic AMP by internalized activated receptor complex. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

  17. Glucagon-like Peptide 1 Conjugated to Recombinant Human Serum Albumin Variants with Modified Neonatal Fc Receptor Binding Properties. Impact on Molecular Structure and Half-Life

    DEFF Research Database (Denmark)

    Bukrinski, Jens T.; Sønderby, Pernille; Antunes, Filipa

    2017-01-01

    Glucagon-like peptide 1 (GLP-1) is a small incretin hormone stimulated by food intake, resulting in an amplification of the insulin response. Though interesting as a drug candidate for the treatment of type 2 diabetes mellitus, its short plasma half-life of less than 3 minutes limits its clinical...... use. A strategy to extend the half-life of GLP-1 utilizes the long half-life of human serum albumin (HSA) by combining the two via chemical conjugation or genetic fusion. HSA has a plasma half-life of around 21 days owing to its interaction with the neonatal Fc receptor (FcRn) expressed in endothelial...... with the available structural information on the FcRn and GLP-1 receptor (GLP-1R) obtained from X-ray crystallography, we can explain the observed in-vitro and in-vivo behaviour. We conclude that the conjugation of GLP-1 to rHSA does not affect the interaction between rHSA and FcRn, while the observed decrease...

  18. The GLP-1 analogue liraglutide improves first-phase insulin secretion and maximal beta-cell secretory capacity over 14 weeks of therapy in subjects with Type 2 diabetes

    DEFF Research Database (Denmark)

    Madsbad, Sten; Vilsbøll, Tina; Brock, Birgitte

    Aims: We investigated the clinical effect of liraglutide, a long- acting GLP-1 analogue, on insulin secretion in Type 2 diabetes. Methods: Thirty-nine subjects (28 completed) from a randomised trial received a hyperglycaemic clamp (20 mM) with intravenous arginine stimulation, and an insulin...... group. Conclusion: In subjects with Type 2 diabetes, 14 weeks’ once-daily liraglutide (1.25 and 1.9 mg/day) markedly improves beta-cell function, significantly increases first-phase insulin secretion and maximal beta-cell secretory capacity....

  19. A glucagon-like peptide-1 receptor agonist reduces intracranial pressure in a rat model of hydrocephalus

    DEFF Research Database (Denmark)

    Botfield, Hannah F; Uldall, Maria S; Westgate, Connar S J

    2017-01-01

    Current therapies for reducing raised intracranial pressure (ICP) under conditions such as idiopathic intracranial hypertension or hydrocephalus have limited efficacy and tolerability. Thus, there is a pressing need to identify alternative drugs. Glucagon-like peptide-1 receptor (GLP-1R) agonists...

  20. Glucagon-like peptide-1 receptor agonists and risk of acute pancreatitis in patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Storgaard, Heidi; Cold, Frederik; Gluud, Lise L

    2017-01-01

    Glucagon-like peptide-1 receptor agonist (GLP-1RAs) labels warn about acute pancreatitis (AP) and impose upon doctors the obligation to inform patients about symptoms of AP. Here we systematically reviewed the risk of AP in randomized placebo-controlled trials (RCTs) investigating the effect of GLP...

  1. Treatment Strategy for Type 2 Diabetes with Obesity: Focus on Glucagon-like Peptide-1 Receptor Agonists.

    Science.gov (United States)

    Ji, Qiuhe

    2017-06-01

    The progressive nature of type 2 diabetes mellitus (T2DM) calls for step-wise intensification of therapy for maintaining normal glycemic levels and lowering cardiovascular (CV) risk. Because obesity is a prominent risk factor and comorbidity of T2DM, it further elevates the CV risk in T2DM. Therefore, it is vital to manage weight, obesity, and glycemic parameters for effective T2DM management. Few oral antidiabetic drugs (sulfonylureas and thiazolidinediones) and insulin are not suitable for obese patients with T2DM because these drugs cause weight gain. The present review discusses the place of glucagon-like peptide-1 receptor agonists (GLP-1RAs) in the treatment of obese patients with T2DM and the significance of these drugs in the prevention of future CV risk in patients with T2DM. A literature search of PubMed and EMBASE was conducted by using the search terms T2DM, GLP-1RAs, obesity, and cardiovascular complication. Randomized controlled trials measuring the effect of GLP-1RAs versus that of placebo on CV outcomes were included in the review. GLP-1RAs have emerged as a therapeutic alternative; these drugs exert their actions by providing glycemic control, improving insulin resistance and ö̇-cell function, and reducing weight. The risk of hypoglycemia with GLP-1RAs is minimal; however, GLP-1RAs are associated with gastrointestinal adverse events and raise concerns regarding pancreatitis. Combining GLP-1RAs with insulin analogues results in higher efficacy, a lowered insulin dose, and reduced insulin-related hypoglycemia and weight gain. Longer acting GLP-1RAs are also associated with improvement in medication adherence. Improvement in CV risk factors such as blood pressure and lipid profile further increases their usability for improving CV outcomes. Overall, the properties of GLP-1RAs make them suitable for combination with oral antidiabetic drugs in the early stages of T2DM and with insulins in the later stages for optimizing comprehensive management of the

  2. Glucagon-Like Peptide-1 Receptor Imaging with [Lys40(Ahx-HYNIC-99mTc/EDDA)NH2]-Exendin-4 for the Diagnosis of Recurrence or Dissemination of Medullary Thyroid Cancer: A Preliminary Report

    Science.gov (United States)

    Pach, D.; Sowa-Staszczak, A.; Jabrocka-Hybel, A.; Stefańska, A.; Tomaszuk, M.; Mikołajczak, R.; Janota, B.; Trofimiuk-Müldner, M.; Przybylik-Mazurek, E.; Hubalewska-Dydejczyk, A.

    2013-01-01

    Introduction. Epidemiological studies on medullary thyroid cancer (MTC) have shown that neither a change in stage at diagnosis nor improvement in survival has occurred during the past 30 years. In patients with detectable serum calcitonin and no clinically apparent disease, a careful search for local recurrence, and nodal or distant metastases, should be performed. Conventional imaging modalities will not show any disease until basal serum calcitonin is at least 150 pg/mL. The objective of the study was to present the first experience with labelled glucagon-like peptide-1 (GLP-1) analogue [Lys40(Ahx-HYNIC-99mTc/EDDA)NH2]-exendin-4 in the visualisation of MTC in humans. Material and Method. Four patients aged 22–74 years (two with sporadic and two with MEN2 syndrome-related disseminated MTC) were enrolled in the study. In all patients, GLP-1 receptor imaging was performed. Results. High-quality images were obtained in all patients. All previously known MTC lesions have been confirmed in GLP-1 scintigraphy. Moreover, one additional liver lesion was detected in sporadic MTC male patient. Conclusions. GLP-1 receptor imaging with [Lys40(Ahx-HYNIC-99mTc/EDDA)NH2]-exendin-4 is able to detect MTC lesions. GLP-1 scintigraphy can serve as a confirmatory test in MTC patients, in whom other imaging procedures are inconsistent. PMID:23606839

  3. Glucagon-Like Peptide-1 Receptor Imaging with [Lys (40) (Ahx-HYNIC- (99 m) Tc/EDDA)NH 2 ]-Exendin-4 for the Diagnosis of Recurrence or Dissemination of Medullary Thyroid Cancer: A Preliminary Report.

    Science.gov (United States)

    Pach, D; Sowa-Staszczak, A; Jabrocka-Hybel, A; Stefańska, A; Tomaszuk, M; Mikołajczak, R; Janota, B; Trofimiuk-Müldner, M; Przybylik-Mazurek, E; Hubalewska-Dydejczyk, A

    2013-01-01

    Introduction. Epidemiological studies on medullary thyroid cancer (MTC) have shown that neither a change in stage at diagnosis nor improvement in survival has occurred during the past 30 years. In patients with detectable serum calcitonin and no clinically apparent disease, a careful search for local recurrence, and nodal or distant metastases, should be performed. Conventional imaging modalities will not show any disease until basal serum calcitonin is at least 150 pg/mL. The objective of the study was to present the first experience with labelled glucagon-like peptide-1 (GLP-1) analogue [Lys(40)(Ahx-HYNIC-(99m)Tc/EDDA)NH2]-exendin-4 in the visualisation of MTC in humans. Material and Method. Four patients aged 22-74 years (two with sporadic and two with MEN2 syndrome-related disseminated MTC) were enrolled in the study. In all patients, GLP-1 receptor imaging was performed. Results. High-quality images were obtained in all patients. All previously known MTC lesions have been confirmed in GLP-1 scintigraphy. Moreover, one additional liver lesion was detected in sporadic MTC male patient. Conclusions. GLP-1 receptor imaging with [Lys(40)(Ahx-HYNIC-(99m)Tc/EDDA)NH2]-exendin-4 is able to detect MTC lesions. GLP-1 scintigraphy can serve as a confirmatory test in MTC patients, in whom other imaging procedures are inconsistent.

  4. Characterization and assembly of a GFP-tagged cylindriform silk into hexameric complexes.

    Science.gov (United States)

    Öster, Carl; Svensson Bonde, Johan; Bülow, Leif; Dicko, Cedric

    2014-04-01

    Spider silk has been studied extensively for its attractive mechanical properties and potential applications in medicine and industry. The production of spider silk, however, has been lagging behind for lack of suitable systems. Our approach focuses on solving the production of spider silk by designing, expressing, purifying and characterizing the silk from cylindriform glands. We show that the cylindriform silk protein, in contrast to the commonly used dragline silk protein, is fully folded and stable in solution. With the help of GFP as a fusion tag we enhanced the expression of the silk protein in Escherichia coli and could optimize the downstream processing. Secondary structures analysis by circular dichroism and FTIR shows that the GFP-silk fusion protein is predominantly α-helical, and that pH can trigger a α- to β-transition resulting in aggregation. Structural analysis by small angle X-ray scattering suggests that the GFP-Silk exists in the form of a hexamer in solution. Copyright © 2013 Wiley Periodicals, Inc.

  5. Effects of insulin analogs and glucagon-like peptide-1 receptor agonists on proliferation and cellular energy metabolism in papillary thyroid cancer

    Directory of Open Access Journals (Sweden)

    He L

    2017-11-01

    Full Text Available Liang He,1,* Siliang Zhang,2,* Xiaowen Zhang,3 Rui Liu,2 Haixia Guan,2 Hao Zhang1 1Department of Thyroid Surgery, The First Hospital of China Medical University, Shenyang, Liaoning, 2Department of Endocrinology and Metabolism, The Endocrine Institute and The Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Hospital of China Medical University, Shenyang, Liaoning, 3Department of Endocrinology and Metabolism, Drum Tower Hospital Affiliated to Nanjing University Medical School, Nanjing, People’s Republic of China *These authors contributed equally to this work Purpose: This study was aimed to investigate the expressions of the insulin receptor (IR, insulin-like growth factor receptor (IGF-1R, and glucagon-like peptide-1 receptor (GLP-1R in normal thyroid tissue, papillary thyroid cancer (PTC tissues, and PTC cells, and to examine the possible role of insulin analogs and GLP-1R agonists in cell proliferation and energy metabolism in PTC cells.Methods: The expressions of IR, IGF-1R, and GLP-1R in PTC tissues and PTC cell lines were detected by immunohistochemistry and western blotting, respectively. Cell proliferation was evaluated by the 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide assay. Levels of members of the phosphoinositol-3 kinase/AKT serine/threonine kinase (Akt and mitogen-activated protein kinase/extracellular signal-regulated kinase (Erk signaling pathways were measured by western blotting. Energy metabolism of PTC cell lines was analyzed using a Seahorse Extracellular Flux analyzer.Results: Three receptors could be detected in both PTC tissues and PTC cell lines. Expressions of IGF-1R and GLP-1R were more obvious in PTC than in normal thyroid cells. Neither insulin, four insulin analogs, and two GLP-1R agonists showed significant effects on the proliferation of PTC cells, nor did they influence the levels of Akt/p-Akt and Erk/p-Erk. None of these antidiabetic agents could change the mitochondrial

  6. Splicing Factor Prp8 Interacts With NES(AR) and Regulates Androgen Receptor in Prostate Cancer Cells.

    Science.gov (United States)

    Wang, Dan; Nguyen, Minh M; Masoodi, Khalid Z; Singh, Prabhpreet; Jing, Yifeng; O'Malley, Katherine; Dar, Javid A; Dhir, Rajiv; Wang, Zhou

    2015-12-01

    Androgen receptor (AR) plays a pivotal role in the development of primary as well as advanced castration-resistant prostate cancer. Previous work in our lab identified a novel nuclear export signal (NES) (NES(AR)) in AR ligand-binding domain essential for AR nucleocytoplasmic trafficking. By characterizing the localization of green fluorescence protein (GFP)-tagged NES(AR), we designed and executed a yeast mutagenesis screen and isolated 7 yeast mutants that failed to display the NES(AR) export function. One of those mutants was identified as the splicing factor pre-mRNA processing factor 8 (Prp8). We further showed that Prp8 could regulate NES(AR) function using short hairpin RNA knockdown of Prp8 coupled with a rapamycin export assay in mammalian cells and knockdown of Prp8 could induce nuclear accumulation of GFP-tagged AR in PC3 cells. Prp8 expression was decreased in castration-resistant LuCaP35 xenograft tumors as compared with androgen-sensitive xenografts. Laser capture microdissection and quantitative PCR showed Prp8 mRNA levels were decreased in human prostate cancer specimens with high Gleason scores. In prostate cancer cells, coimmunoprecipitation and deletion mutagenesis revealed a physical interaction between Prp8 and AR mainly mediated by NES(AR). Luciferase assay with prostate specific antigen promoter-driven reporter demonstrated that Prp8 regulated AR transcription activity in prostate cancer cells. Interestingly, Prp8 knockdown also increased polyubiquitination of endogenous AR. This may be 1 possible mechanism by which it modulates AR activity. These results show that Prp8 is a novel AR cofactor that interacts with NES(AR) and regulates AR function in prostate cancer cells.

  7. The cytoplasmic domain close to the transmembrane region of the glucagon-like peptide-1 receptor contains sequence elements that regulate agonist-dependent internalisation.

    Science.gov (United States)

    Vázquez, Patricia; Roncero, Isabel; Blázquez, Enrique; Alvarez, Elvira

    2005-07-01

    In order to gain better insight into the molecular events involved in the signal transduction generated through glucagon-like peptide-1 (GLP-1) receptors, we tested the effect of deletions and point mutations within the cytoplasmic tail of this receptor with a view to establishing relationships between signal transduction desensitisation and receptor internalisation. Wild-type and truncated (deletion of the last 27 amino acids (GLPR 435R) and deletion of 44 amino acids (GLPR 418R)) GLP-1 receptors bound the agonist with similar affinity. Deletion of the last 27 amino acids decreased the internalisation rate by 78%, while deletion of 44 amino acids containing all the phosphorylation sites hitherto described in this receptor decreased the internalisation rate by only 47%. Binding of the ligand to both receptors stimulated adenylyl cyclase. In contrast, deletion of the region containing amino acids 419 to 435 (GLPR 419delta435) increased the internalisation rate by 268%, and the replacement of EVQ(408-410) by alanine (GLPR A(408-410)) increased this process to 296%. In both receptors, the efficacy in stimulating adenylate cyclase was decreased. All the receptors studied were internalised by coated pits, except for the receptor with a deletion of the last 44 amino acids, which also had a faster resensitisation rate. Our findings indicate that the neighbouring trans-membrane domain of the carboxyl-terminal tail of the GLP-1 receptor contains sequence elements that regulate agonist-dependent internalisation and transmembrane signalling.

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

    DEFF Research Database (Denmark)

    Engelstoft, M S; Schwartz, T W

    2016-01-01

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

  9. Role of central nervous system glucagon-like Peptide-1 receptors in enteric glucose sensing.

    Science.gov (United States)

    Knauf, Claude; Cani, Patrice D; Kim, Dong-Hoon; Iglesias, Miguel A; Chabo, Chantal; Waget, Aurélie; Colom, André; Rastrelli, Sophie; Delzenne, Nathalie M; Drucker, Daniel J; Seeley, Randy J; Burcelin, Remy

    2008-10-01

    Ingested glucose is detected by specialized sensors in the enteric/hepatoportal vein, which send neural signals to the brain, which in turn regulates key peripheral tissues. Hence, impairment in the control of enteric-neural glucose sensing could contribute to disordered glucose homeostasis. The aim of this study was to determine the cells in the brain targeted by the activation of the enteric glucose-sensing system. We selectively activated the axis in mice using a low-rate intragastric glucose infusion in wild-type and glucagon-like peptide-1 (GLP-1) receptor knockout mice, neuropeptide Y-and proopiomelanocortin-green fluorescent protein-expressing mice, and high-fat diet diabetic mice. We quantified the whole-body glucose utilization rate and the pattern of c-Fos positive in the brain. Enteric glucose increased muscle glycogen synthesis by 30% and regulates c-Fos expression in the brainstem and the hypothalamus. Moreover, the synthesis of muscle glycogen was diminished after central infusion of the GLP-1 receptor (GLP-1Rc) antagonist Exendin 9-39 and abolished in GLP-1Rc knockout mice. Gut-glucose-sensitive c-Fos-positive cells of the arcuate nucleus colocalized with neuropeptide Y-positive neurons but not with proopiomelanocortin-positive neurons. Furthermore, high-fat feeding prevented the enteric activation of c-Fos expression. We conclude that the gut-glucose sensor modulates peripheral glucose metabolism through a nutrient-sensitive mechanism, which requires brain GLP-1Rc signaling and is impaired during diabetes.

  10. Insulinoma imaging with glucagon-like peptide-1 receptor targeting probe (18)F-FBEM-Cys (39)-exendin-4.

    Science.gov (United States)

    Xu, Yuping; Pan, Donghui; Xu, Qing; Zhu, Chen; Wang, Lizhen; Chen, Fei; Yang, Runlin; Luo, Shineng; Yang, Min

    2014-09-01

    Glucagon-like peptide-1 receptor (GLP-1R) is a specific target for insulinomas imaging since it is overexpressed in the tumor. Exendin-4 exhibits high affinity for the GLP-1R. In this study, a novel (18)F-labeled exendin-4 analog, (18)F-FBEM-Cys(39)-exendin-4, was synthesized and its potentials for GLP-1R imaging were also evaluated. (18)F-FBEM was synthesized by coupling (18)F-fluorobenzoic acid ((18)F-FBA) with N-(2-aminoethyl) maleimide, and the reaction conditions were optimized. Cys(39)-exendin-4 was then conjugated with (18)F-FBEM to obtain (18)F-FBEM-Cys(39)-exendin-4. The GLP-1R targeting potential and pharmacokinetic profile of the tracer were analyzed in INS-1 insulinoma and MDA-MB-435 breast tumor model, respectively. Under the optimal conditions, the yield of radiolabeled (18)F-FBEM was 49.1 ± 2.0 % (based on (18)F-FBA, non-decay corrected). The yield of (18)F-FBEM-Cys(39)-exendin-4 was 35.1 ± 2.6 % (based on the starting (18)F-FBEM, non-decay corrected). The radiochemical purity of (18)F-FBEM-Cys(39)-exendin-4 is >95 %, and the specific activity was at least 35 GBq/μmol. The GLP-1R-positive INS-1 insulinoma xenograft was clearly visible with good contrast to background, whereas GLP-1R-negative MDA-MB435 breast tumor was barely visible. Low levels of radioactivity were also detected at pancreas and lungs due to few GLP-1R expressions. GLP-1R binding specificity was demonstrated by reduced INS-1 tumor uptake of the tracer after coinjection with an excess of unlabeled Cys(39)-exendin-4 at 1 h postinjection. The thiol-reactive reagent, (18)F-FBEM, was prepared with high yield and successfully conjugated to Cys(39)-exendin-4. Favorable preclinical data showing specific and effective tumor targeting by (18)F-FBEM-Cys(39)-exendin-4 suggest that the tracer may be a potential probe for insulinomas imaging.

  11. Oleic acid and glucose regulate glucagon-like peptide 1 receptor expression in a rat pancreatic ductal cell line

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Leshuai W.; McMahon Tobin, Grainne A.; Rouse, Rodney L., E-mail: rodney.rouse@fda.hhs.gov

    2012-10-15

    The glucagon-like peptide 1 receptor (GLP1R) plays a critical role in glucose metabolism and has become an important target for a growing class of drugs designed to treat type 2 diabetes. In vitro studies were designed to investigate the effect of the GLP1R agonist, exenatide (Ex4), in “on-target” RIN-5mF (islet) cells as well as in “off-target” AR42J (acinar) and DSL-6A/C1 (ductal) cells in a diabetic environment. Ex4 increased islet cell proliferation but did not affect acinar cells or ductal cells at relevant concentrations. A high caloric, high fat diet is a risk factor for impaired glucose tolerance and type-2 diabetes. An in vitro Oleic acid (OA) model was used to investigate the effect of Ex4 in a high calorie, high fat environment. At 0.1 and 0.4 mM, OA mildly decreased the proliferation of all pancreatic cell types. Ex4 did not potentiate the inhibitory effect of OA on cell proliferation. Akt phosphorylation in response to Ex4 was diminished in OA-treated ductal cells. GLP1R protein detected by western blot was time and concentration dependently decreased after glucose stimulation in OA-treated ductal cells. In ductal cells, OA treatment altered the intracellular localization of GLP1R and its co-localization with early endosome and recycling endosomes. Chloroquine (lysosomal inhibitor), N-acetyl-L-cysteine (reactive oxygen species scavenger) and wortmannin (a phosphatidylinositol-3-kinase inhibitor), fully or partially, rescued GLP1R protein in OA-pretreated, glucose-stimulated ductal cells. The impact of altered regulation on phenotype/function is presently unknown. However, these data suggest that GLP1R regulation in ductal cells can be altered by a high fat, high calorie environment. -- Highlights: ► Exenatide did not inhibit islet, acinar or ductal cell proliferation. ► GLP1R protein decreased after glucose stimulation in oleic acid-treated ductal cells. ► Oleic acid treatment altered localization of GLP1R with early and recycling

  12. Oleic acid and glucose regulate glucagon-like peptide 1 receptor expression in a rat pancreatic ductal cell line

    International Nuclear Information System (INIS)

    Zhang, Leshuai W.; McMahon Tobin, Grainne A.; Rouse, Rodney L.

    2012-01-01

    The glucagon-like peptide 1 receptor (GLP1R) plays a critical role in glucose metabolism and has become an important target for a growing class of drugs designed to treat type 2 diabetes. In vitro studies were designed to investigate the effect of the GLP1R agonist, exenatide (Ex4), in “on-target” RIN-5mF (islet) cells as well as in “off-target” AR42J (acinar) and DSL-6A/C1 (ductal) cells in a diabetic environment. Ex4 increased islet cell proliferation but did not affect acinar cells or ductal cells at relevant concentrations. A high caloric, high fat diet is a risk factor for impaired glucose tolerance and type-2 diabetes. An in vitro Oleic acid (OA) model was used to investigate the effect of Ex4 in a high calorie, high fat environment. At 0.1 and 0.4 mM, OA mildly decreased the proliferation of all pancreatic cell types. Ex4 did not potentiate the inhibitory effect of OA on cell proliferation. Akt phosphorylation in response to Ex4 was diminished in OA-treated ductal cells. GLP1R protein detected by western blot was time and concentration dependently decreased after glucose stimulation in OA-treated ductal cells. In ductal cells, OA treatment altered the intracellular localization of GLP1R and its co-localization with early endosome and recycling endosomes. Chloroquine (lysosomal inhibitor), N-acetyl-L-cysteine (reactive oxygen species scavenger) and wortmannin (a phosphatidylinositol-3-kinase inhibitor), fully or partially, rescued GLP1R protein in OA-pretreated, glucose-stimulated ductal cells. The impact of altered regulation on phenotype/function is presently unknown. However, these data suggest that GLP1R regulation in ductal cells can be altered by a high fat, high calorie environment. -- Highlights: ► Exenatide did not inhibit islet, acinar or ductal cell proliferation. ► GLP1R protein decreased after glucose stimulation in oleic acid-treated ductal cells. ► Oleic acid treatment altered localization of GLP1R with early and recycling

  13. Divergent Label-free Cell Phenotypic Pharmacology of Ligands at the Overexpressed β2-Adrenergic Receptors

    Science.gov (United States)

    Ferrie, Ann M.; Sun, Haiyan; Zaytseva, Natalya; Fang, Ye

    2014-01-01

    We present subclone sensitive cell phenotypic pharmacology of ligands at the β2-adrenergic receptor (β2-AR) stably expressed in HEK-293 cells. The parental cell line was transfected with green fluorescent protein (GFP)-tagged β2-AR. Four stable subclones were established and used to profile a library of sixty-nine AR ligands. Dynamic mass redistribution (DMR) profiling resulted in a pharmacological activity map suggesting that HEK293 endogenously expresses functional Gi-coupled α2-AR and Gs-coupled β2-AR, and the label-free cell phenotypic activity of AR ligands are subclone dependent. Pathway deconvolution revealed that the DMR of epinephrine is originated mostly from the remodeling of actin microfilaments and adhesion complexes, to less extent from the microtubule networks and receptor trafficking, and certain agonists displayed different efficacy towards the cAMP-Epac pathway. We demonstrate that receptor signaling and ligand pharmacology is sensitive to the receptor expression level, and the organization of the receptor and its signaling circuitry.

  14. First cytoplasmic loop of glucagon-like peptide-1 receptor can function at the third cytoplasmic loop position of rhodopsin.

    Science.gov (United States)

    Yamashita, Takahiro; Tose, Koji; Shichida, Yoshinori

    2008-01-01

    G protein-coupled receptors (GPCRs) are classified into several families based on their amino acid sequences. In family 1, GPCRs such as rhodopsin and adrenergic receptor, the structure-function relationship has been extensively investigated to demonstrate that exposure of the third cytoplasmic loop is essential for selective G protein activation. In contrast, much less is known about other families. Here we prepared chimeric mutants between Gt-coupled rhodopsin and Gi/Go- and Gs-coupled glucagon-like peptide-1 (GLP-1) receptor of family 2 and tried to identify the loop region that functions at the third cytoplasmic loop position of rhodopsin. We succeeded in expressing a mutant having the first cytoplasmic loop of GLP-1 receptor and found that this mutant activated Gi and Go efficiently but did not activate Gt. Moreover, the rhodopsin mutant having the first loop of Gs-coupled secretin receptor of family 2 decreased the Gi and Go activation efficiencies. Therefore, the first loop of GLP-1 receptor would share a similar role to the third loop of rhodopsin in G protein activation. This result strongly suggested that different families of GPCRs have maintained molecular architectures of their ancestral types to generate a common mechanism, namely exposure of the cytoplasmic loop, to activate peripheral G protein.

  15. Farnesoid X receptor induces Takeda G-protein receptor 5 cross-talk to regulate bile acid synthesis and hepatic metabolism.

    Science.gov (United States)

    Pathak, Preeti; Liu, Hailiang; Boehme, Shannon; Xie, Cen; Krausz, Kristopher W; Gonzalez, Frank; Chiang, John Y L

    2017-06-30

    The bile acid-activated receptors, nuclear farnesoid X receptor (FXR) and the membrane Takeda G-protein receptor 5 (TGR5), are known to improve glucose and insulin sensitivity in obese and diabetic mice. However, the metabolic roles of these two receptors and the underlying mechanisms are incompletely understood. Here, we studied the effects of the dual FXR and TGR5 agonist INT-767 on hepatic bile acid synthesis and intestinal secretion of glucagon-like peptide-1 (GLP-1) in wild-type, Fxr -/- , and Tgr5 -/- mice. INT-767 efficaciously stimulated intracellular Ca 2+ levels, cAMP activity, and GLP-1 secretion and improved glucose and lipid metabolism more than did the FXR-selective obeticholic acid and TGR5-selective INT-777 agonists. Interestingly, INT-767 reduced expression of the genes in the classic bile acid synthesis pathway but induced those in the alternative pathway, which is consistent with decreased taurocholic acid and increased tauromuricholic acids in bile. Furthermore, FXR activation induced expression of FXR target genes, including fibroblast growth factor 15, and unexpectedly Tgr5 and prohormone convertase 1/3 gene expression in the ileum. We identified an FXR-responsive element on the Tgr5 gene promoter. Fxr -/- and Tgr5 -/- mice exhibited reduced GLP-1 secretion, which was stimulated by INT-767 in the Tgr5 -/- mice but not in the Fxr -/- mice. Our findings uncovered a novel mechanism in which INT-767 activation of FXR induces Tgr5 gene expression and increases Ca 2+ levels and cAMP activity to stimulate GLP-1 secretion and improve hepatic glucose and lipid metabolism in high-fat diet-induced obese mice. Activation of both FXR and TGR5 may therefore represent an effective therapy for managing hepatic steatosis, obesity, and diabetes. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. Treatment of type 2 diabetes with glucagon-like peptide-1 receptor agonists

    DEFF Research Database (Denmark)

    Hansen, K B; Knop, F K; Holst, Jens Juul

    2009-01-01

    of hypoglycaemia with GLP-1 receptor agonists is low, the compounds have clinically relevant effects on body weight, and data are suggesting beneficial effects on cardiovascular risk factors. Exenatide was released in 2005 for the treatment of type 2 diabetes and liraglutide is expected to be approved by the Food......The incretin system is an area of great interest for the development of new therapies for the management of type 2 diabetes. Existing antidiabetic drugs are often insufficient at getting patients to glycaemic goals. Furthermore, current treatment modalities are not able to prevent the continued...... ongoing decline in pancreatic beta-cell function and, lastly, they have a number of side effects including hypoglycaemia and weight gain. Glucagon-like peptide-1 (GLP-1) receptor agonists are a new class of pharmacological agents, which improve glucose homeostasis in a multifaceted way. Their effects...

  17. Clathrin-dependent internalization, signaling, and metabolic processing of guanylyl cyclase/natriuretic peptide receptor-A.

    Science.gov (United States)

    Somanna, Naveen K; Mani, Indra; Tripathi, Satyabha; Pandey, Kailash N

    2018-04-01

    Cardiac hormones, atrial and brain natriuretic peptides (ANP and BNP), have pivotal roles in renal hemodynamics, neuroendocrine signaling, blood pressure regulation, and cardiovascular homeostasis. Binding of ANP and BNP to the guanylyl cyclase/natriuretic peptide receptor-A (GC-A/NPRA) induces rapid internalization and trafficking of the receptor via endolysosomal compartments, with concurrent generation of cGMP. However, the mechanisms of the endocytotic processes of NPRA are not well understood. The present study, using 125 I-ANP binding assay and confocal microscopy, examined the function of dynamin in the internalization of NPRA in stably transfected human embryonic kidney-293 (HEK-293) cells. Treatment of recombinant HEK-293 cells with ANP time-dependently accelerated the internalization of receptor from the cell surface to the cell interior. However, the internalization of ligand-receptor complexes of NPRA was drastically decreased by the specific inhibitors of clathrin- and dynamin-dependent receptor internalization, almost 85% by monodansylcadaverine, 80% by chlorpromazine, and 90% by mutant dynamin, which are specific blockers of endocytic vesicle formation. Visualizing the internalization of NPRA and enhanced GFP-tagged NPRA in HEK-293 cells by confocal microscopy demonstrated the formation of endocytic vesicles after 5 min of ANP treatment; this effect was blocked by the inhibitors of clathrin and by mutant dynamin construct. Our results suggest that NPRA undergoes internalization via clathrin-mediated endocytosis as part of its normal itinerary, including trafficking, signaling, and metabolic degradation.

  18. Biscuits with No Added Sugar Containing Stevia, Coffee Fibre and Fructooligosaccharides Modifies α-Glucosidase Activity and the Release of GLP-1 from HuTu-80 Cells and Serotonin from Caco-2 Cells after In Vitro Digestion.

    Science.gov (United States)

    Martinez-Saez, Nuria; Hochkogler, Christina Maria; Somoza, Veronika; Del Castillo, Maria Dolores

    2017-07-04

    This study assessed the in vitro effects of the bioaccessible food components released during the simulated human digestion of a coffee fibre-containing biscuit (CFB) on α-glucosidase activity, antioxidant capacity and satiety hormones. Digest of CFB presented a significantly ( p < 0.05) lower amount of sugar (68.6 mg/g) and a higher antioxidant capacity (15.1 mg chlorogenic acid eq./g) than that of a sucrose-containing biscuit (SCB). The CFB significantly reduced ( p < 0.05) α-glucosidase activity (IC50 = 3.3 mg/mL) compared to the SCB (IC50 = 6.2 mg/mL). Serotonin and glucagon-like peptide-1 (GLP-1) release by differentiated Caco-2 and HuTu-80 cells, respectively, was stimulated by the CFB (355% at a concentration of 0.5 mg/mL and 278% at a concentration of 0.05 mg/mL) to the same order of magnitude as those of the SCB. To summarize, the CFB was demonstrated to reduce monosaccharide bioaccessibility, to inhibit a diabetes-related digestive enzyme, and to improve the release of satiety hormones.

  19. Glucagon-Like Peptide-1 Receptor Agonist Use and Renal Impairment: A Retrospective Analysis of an Electronic Health Records Database in the U.S. Population.

    Science.gov (United States)

    Boye, Kristina S; Botros, Fady T; Haupt, Axel; Woodward, Brad; Lage, Maureen J

    2018-04-01

    The study characterizes the use of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) in patients with type 2 diabetes (T2D) with and without renal impairment and examines the effects of such use on the clinical outcomes of estimated glomerular filtration rate (eGFR) and glycated hemoglobin (A1c). Data from the Practice Fusion electronic health records database from 1 January 2012 through 30 April 2015 were used. Adults with T2D who received serum creatinine laboratory tests and initiated therapy with a GLP-1 RA (N = 3225) or other glucose-lowering agent (GLA) (N = 37,074) were included in the analysis. The GLP-1 RA cohort was matched to cohorts initiating therapy any other GLA, and multivariable analyses examined the association between GLP-1 RA use and changes in eGFR or A1c at 1 year after therapy initiation. In this study, only 5.7% of patients with an eGFR of Eli Lilly and Company.

  20. Differential Requirement of the Extracellular Domain in Activation of Class B G Protein-coupled Receptors.

    Science.gov (United States)

    Zhao, Li-Hua; Yin, Yanting; Yang, Dehua; Liu, Bo; Hou, Li; Wang, Xiaoxi; Pal, Kuntal; Jiang, Yi; Feng, Yang; Cai, Xiaoqing; Dai, Antao; Liu, Mingyao; Wang, Ming-Wei; Melcher, Karsten; Xu, H Eric

    2016-07-15

    G protein-coupled receptors (GPCRs) from the secretin-like (class B) family are key players in hormonal homeostasis and are important drug targets for the treatment of metabolic disorders and neuronal diseases. They consist of a large N-terminal extracellular domain (ECD) and a transmembrane domain (TMD) with the GPCR signature of seven transmembrane helices. Class B GPCRs are activated by peptide hormones with their C termini bound to the receptor ECD and their N termini bound to the TMD. It is thought that the ECD functions as an affinity trap to bind and localize the hormone to the receptor. This in turn would allow the hormone N terminus to insert into the TMD and induce conformational changes of the TMD to activate downstream signaling. In contrast to this prevailing model, we demonstrate that human class B GPCRs vary widely in their requirement of the ECD for activation. In one group, represented by corticotrophin-releasing factor receptor 1 (CRF1R), parathyroid hormone receptor (PTH1R), and pituitary adenylate cyclase activating polypeptide type 1 receptor (PAC1R), the ECD requirement for high affinity hormone binding can be bypassed by induced proximity and mass action effects, whereas in the other group, represented by glucagon receptor (GCGR) and glucagon-like peptide-1 receptor (GLP-1R), the ECD is required for signaling even when the hormone is covalently linked to the TMD. Furthermore, the activation of GLP-1R by small molecules that interact with the intracellular side of the receptor is dependent on the presence of its ECD, suggesting a direct role of the ECD in GLP-1R activation. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. Effects of Substitution, and Adding of Carbohydrate and Fat to Whey-Protein on Energy Intake, Appetite, Gastric Emptying, Glucose, Insulin, Ghrelin, CCK and GLP-1 in Healthy Older Men—A Randomized Controlled Trial

    Directory of Open Access Journals (Sweden)

    Caroline Giezenaar

    2018-01-01

    Full Text Available Protein-rich supplements are used widely for the management of malnutrition in the elderly. We reported previously that the suppression of energy intake by whey protein is less in older than younger adults. The aim was to determine the effects of substitution, and adding of carbohydrate and fat to whey protein, on ad libitum energy intake from a buffet meal (180–210 min, gastric emptying (3D-ultrasonography, plasma gut hormone concentrations (0–180 min and appetite (visual analogue scales, in healthy older men. In a randomized, double-blind order, 13 older men (75 ± 2 years ingested drinks (~450 mL containing: (i 70 g whey protein (280 kcal; ‘P280’; (ii 14 g protein, 28 g carbohydrate, 12.4 g fat (280 kcal; ‘M280’; (iii 70 g protein, 28 g carbohydrate, 12.4 g fat (504 kcal; ‘M504’; or (iv control (~2 kcal. The caloric drinks, compared to a control, did not suppress appetite or energy intake; there was an increase in total energy intake (drink + meal, p < 0.05, which was increased most by the M504-drink. P280- and M504-drink ingestion were associated with slower a gastric-emptying time (n = 9, lower ghrelin, and higher cholecystokinin (CCK and glucagon-like peptide-1 (GLP-1 than M280 (p < 0.05. Glucose and insulin were increased most by the mixed-macronutrient drinks (p < 0.05. In conclusion, energy intake was not suppressed, compared to a control, and particularly whey protein, affected gastric emptying and gut hormone responses.

  2. Alleviation of insulin resistance and liver damage by oral administration of Imm124-E is mediated by increased Tregs and associated with increased serum GLP-1 and adiponectin: results of a phase I/II clinical trial in NASH

    Directory of Open Access Journals (Sweden)

    Mizrahi M

    2012-12-01

    Full Text Available Meir Mizrahi,1 Yehudit Shabat,1 Ami Ben Ya'acov,1 Gadi Lalazar,1 Tomer Adar,1 Victor Wong,2 Brian Muller,2 Grant Rawlin,2 Yaron Ilan11Liver Unit, Hebrew University-Hadassah Medical Center, Jerusalem, Israel; 2Immuron Limited, North Melbourne, AustraliaBackground: Nonalcoholic steatohepatitis (NASH is considered to be part of the nonalcoholic fatty liver disorders and its incidence is increasing. Imm124-E (Immuron Ltd, Melbourne, Australia, containing hyperimmune bovine colostrum, has been shown to exert an immunomodulatory effect and to alleviate target organ damage in animal models of NASH. The aim of our study was to determine the safety and efficacy of oral administration of Imm124-E to patients with insulin resistance and NASH.Methods: In an open-label trial, ten patients with biopsy-proven NASH and insulin resistance were orally treated with Imm124-E for 30 days.Results: Oral administration of Imm124-E was safe, and no side effects were noted. Alleviation of insulin resistance was reflected by significantly improved hemoglobin A1c (HbA1c values in all ten treated patients. For between five and eight responders, the following effects were noted: a decrease in fasting glucose levels; improved oral glucose tolerance test (OGGT and homeostatic model assessment insulin resistance (HOMA scores; and alleviation in lipid profile. These effects were accompanied by increased serum levels of glucagon-like peptide 1 (GLP-1, adiponectin and T regulatory cells.Conclusion: Hyperimmune colostrum alleviates NASH.Keywords: NASH, anti-LPS, diabetes, adipokines, regulatory T cells

  3. Novel cell-based assay for detection of thyroid receptor beta-interacting environmental contaminants.

    Science.gov (United States)

    Stavreva, Diana A; Varticovski, Lyuba; Levkova, Ludmila; George, Anuja A; Davis, Luke; Pegoraro, Gianluca; Blazer, Vicki; Iwanowicz, Luke; Hager, Gordon L

    2016-08-10

    Even though the presence of endocrine disrupting chemicals (EDCs) with thyroid hormone (TH)-like activities in the environment is a major health concern, the methods for their efficient detection and monitoring are still limited. Here we describe a novel cell assay, based on the translocation of a green fluorescent protein (GFP)-tagged chimeric molecule of glucocorticoid receptor (GR) and the thyroid receptor beta (TRβ) from the cytoplasm to the nucleus in the presence of TR ligands. Unlike the constitutively nuclear TRβ, this GFP-GR-TRβ chimera is cytoplasmic in the absence of hormone while translocating to the nucleus in a time- and concentration-dependent manner upon stimulation with triiodothyronine (T3) and thyroid hormone analogue, TRIAC, while the reverse triiodothyronine (3,3',5'-triiodothyronine, or rT3) was inactive. Moreover, GFP-GR-TRβ chimera does not show any cross-reactivity with the GR-activating hormones, thus providing a clean system for the screening of TR beta-interacting EDCs. Using this assay, we demonstrated that Bisphenol A (BPA) and 3,3',5,5'-Tetrabromobisphenol (TBBPA) induced GFP-GR-TRβ translocation at micro molar concentrations. We screened over 100 concentrated water samples from different geographic locations in the United States and detected a low, but reproducible contamination in 53% of the samples. This system provides a novel high-throughput approach for screening for endocrine disrupting chemicals (EDCs) interacting with TR beta. Published by Elsevier Ireland Ltd.

  4. Effects of glucagon-like peptide-1 receptor agonists on cardiovascular risk factors

    DEFF Research Database (Denmark)

    Dalsgaard, Niels B; Vilsbøll, Tina; Knop, Filip K

    2018-01-01

    with continuous-acting treatments, while large GLP-1RAs had a reduced effect on body weight compared with small GLP-1RAs. For glycaemic control, short-acting GLP-1RAs had a greater impact on postprandial glucose levels vs continuous-acting GLP-1RAs, but for fasting plasma glucose levels and HbA1c, continuous...

  5. Efficacy and Acceptability of Glycemic Control of Glucagon-Like Peptide-1 Receptor Agonists among Type 2 Diabetes: A Systematic Review and Network Meta-Analysis.

    Directory of Open Access Journals (Sweden)

    Zhixia Li

    Full Text Available To synthesize current evidence of the impact of Glucagon-like peptide-1 receptor agonists (GLP-1 RAs on hypoglycemia, treatment discontinuation and glycemic level in patients with type 2 diabetes.Systematic review and network meta-analysis.Literature search (Medline, Embase, the Cochrane library, website of clinical trial, bibliographies of published systematic reviews.Randomized controlled trials with available data comparing GLP-1 RAs with placebo or traditional anti-diabetic drugs in patients with type 2 diabetes.Traditional pairwise meta-analyses within DerSimonian-Laird random effects model and network meta-analysis within a Bayesian framework were performed to calculate odds ratios for the incidence of hypoglycemia, treatment discontinuation, HbA1c<7.0% and HbA1c<6.5%. Ranking probabilities for all treatments were estimated to obtain a treatment hierarchy using the surface under the cumulative ranking curve (SUCRA and mean ranks.78 trials with 13 treatments were included. Overall, all GLP-1 RAs except for albiglutide increased the risk of hypoglycemia when compared to placebo. Reduction in the incidence of hypoglycemia was found for all GLP-1 RAs versus insulin (except for dulaglutide and sulphonylureas. For the incidence of treatment discontinuation, increase was found for exenatide, liraglutide, lixisenatide and taspoglutide versus placebo, insulin and sitagliptin. For glycemic level, decrease was found for all GLP-1 RAs versus placebo. Dulaglutide, exenatide long-acting release (exe_lar, liraglutide and taspoglutide had significant lowering effect when compared with sitagliptin (HbA1c<7.0% and insulin (HbA1c<6.5%. Finally, according to SUCRAs, placebo, thiazolidinediones and albiglutide had the best decrease effect on hypoglycemia; sulphanylureas, sitagliptin and insulin decrease the incidence of treatment discontinuation most; exe_lar and dulaglutide had the highest impact on glycemic level among 13 treatments.Among 13 treatments, GLP

  6. Update in Cardiovascular Safety of Glucagon Like Peptide-1 Receptor Agonists In Patients With Type 2 Diabetes. A Mixed Treatment Comparison Meta-Analysis of Randomised Controlled Trials.

    Science.gov (United States)

    Al Yami, Majed S; Alfayez, Osamah M; Alsheikh, Razan

    2018-03-29

    The aim of this mixed treatment comparison (MTC) meta-analysis was to determine glucagon like peptide-1 (GLP-1) receptor agonists' effects on cardiovascular (CV) outcomes in patients with type 2 diabetes (T2DM). A comprehensive, systematic review was conducted using EMBASE and Medline databases. All included trials were large CV outcome trials of GLP-1 agonists versus placebo in T2DM. The primary outcomes of this MTC meta-analysis were death from CV causes, non-fatal MI, and non-fatal stroke. Hospitalisation for heart failure (HF) was evaluated as a secondary endpoint. A total of four trials, including 33,457 patients, met eligibility criteria and were retained for the meta-analysis. Our pairwise meta-analysis results showed a 13% reduction in death from cardiovascular causes in patients who received GLP-1 agonists versus placebo (RR 0.87, 95% CI: 0.78-0.96). However, no statistically significant reduction was observed with GLP-1 agonists in terms of reducing non-fatal MI (RR 0.95, 95% CI: 0.86-1.04), non-fatal stroke events (RR 0.89, 95% CI: 0.76-1.03), and rates of HF hospitalisation (RR 0.94, 95% CI: 0.84-1.04). The network meta-analysis (NMA) showed no significant differences among all the interventions. Glucagon like peptide-1 therapy was associated with a significant reduction in cardiovascular (CV) death. However, GLP-1 agonists seem to have a safety profile comparable to placebo in terms of reducing non-fatal myocardial infarction (MI), non-fatal stroke events, and rates of HF hospitalisation. Copyright © 2018 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

  7. [6]-Gingerol, from Zingiber officinale, potentiates GLP-1 mediated glucose-stimulated insulin secretion pathway in pancreatic β-cells and increases RAB8/RAB10-regulated membrane presentation of GLUT4 transporters in skeletal muscle to improve hyperglycemia in Leprdb/db type 2 diabetic mice.

    Science.gov (United States)

    Samad, Mehdi Bin; Mohsin, Md Nurul Absar Bin; Razu, Bodiul Alam; Hossain, Mohammad Tashnim; Mahzabeen, Sinayat; Unnoor, Naziat; Muna, Ishrat Aklima; Akhter, Farjana; Kabir, Ashraf Ul; Hannan, J M A

    2017-08-09

    [6]-Gingerol, a major component of Zingiber officinale, was previously reported to ameliorate hyperglycemia in type 2 diabetic mice. Endocrine signaling is involved in insulin secretion and is perturbed in db/db Type-2 diabetic mice. [6]-Gingerol was reported to restore the disrupted endocrine signaling in rodents. In this current study on Lepr db/db diabetic mice, we investigated the involvement of endocrine pathway in the insulin secretagogue activity of [6]-Gingerol and the mechanism(s) through which [6]-Gingerol ameliorates hyperglycemia. Lepr db/db type 2 diabetic mice were orally administered a daily dose of [6]-Gingerol (200 mg/kg) for 28 days. We measured the plasma levels of different endocrine hormones in fasting and fed conditions. GLP-1 levels were modulated using pharmacological approaches, and cAMP/PKA pathway for insulin secretion was assessed by qRT-PCR and ELISA in isolated pancreatic islets. Total skeletal muscle and its membrane fractions were used to measure glycogen synthase 1 level and Glut4 expression and protein levels. 4-weeks treatment of [6]-Gingerol dramatically increased glucose-stimulated insulin secretion and improved glucose tolerance. Plasma GLP-1 was found to be significantly elevated in the treated mice. Pharmacological intervention of GLP-1 levels regulated the effect of [6]-Gingerol on insulin secretion. Mechanistically, [6]-Gingerol treatment upregulated and activated cAMP, PKA, and CREB in the pancreatic islets, which are critical components of GLP-1-mediated insulin secretion pathway. [6]-Gingerol upregulated both Rab27a GTPase and its effector protein Slp4-a expression in isolated islets, which regulates the exocytosis of insulin-containing dense-core granules. [6]-Gingerol treatment improved skeletal glycogen storage by increased glycogen synthase 1 activity. Additionally, GLUT4 transporters were highly abundant in the membrane of the skeletal myocytes, which could be explained by the increased expression of Rab8 and Rab

  8. Ectopic Expression of α6 and δ GABAA Receptor Subunits in Hilar Somatostatin Neurons Increases Tonic Inhibition and Alters Network Activity in the Dentate Gyrus

    Science.gov (United States)

    Tong, Xiaoping; Peng, Zechun; Zhang, Nianhui; Cetina, Yliana; Huang, Christine S.; Wallner, Martin; Otis, Thomas S.

    2015-01-01

    The role of GABAA receptor (GABAAR)-mediated tonic inhibition in interneurons remains unclear and may vary among subgroups. Somatostatin (SOM) interneurons in the hilus of the dentate gyrus show negligible expression of nonsynaptic GABAAR subunits and very low tonic inhibition. To determine the effects of ectopic expression of tonic GABAAR subtypes in these neurons, Cre-dependent viral vectors were used to express GFP-tagged GABAAR subunits (α6 and δ) selectively in hilar SOM neurons in SOM-Cre mice. In single-transfected animals, immunohistochemistry demonstrated strong expression of either the α6 or δ subunit; in cotransfected animals, both subunits were consistently expressed in the same neurons. Electrophysiology revealed a robust increase of tonic current, with progressively larger increases following transfection of δ, α6, and α6/δ subunits, respectively, indicating formation of functional receptors in all conditions and likely coassembly of the subunits in the same receptor following cotransfection. An in vitro model of repetitive bursting was used to determine the effects of increased tonic inhibition in hilar SOM interneurons on circuit activity in the dentate gyrus. Upon cotransfection, the frequency of GABAAR-mediated bursting in granule cells was reduced, consistent with a reduction in synchronous firing among hilar SOM interneurons. Moreover, in vivo studies of Fos expression demonstrated reduced activation of α6/δ-cotransfected neurons following acute seizure induction by pentylenetetrazole. The findings demonstrate that increasing tonic inhibition in hilar SOM interneurons can alter dentate gyrus circuit activity during strong stimulation and suggest that tonic inhibition of interneurons could play a role in regulating excessive synchrony within the network. SIGNIFICANCE STATEMENT In contrast to many hippocampal interneurons, somatostatin (SOM) neurons in the hilus of the dentate gyrus have very low levels of nonsynaptic GABAARs and exhibit

  9. Efficacy and safety of once-weekly GLP-1 receptor agonist albiglutide (HARMONY 2): 52 week primary endpoint results from a randomised, placebo-controlled trial in patients with type 2 diabetes mellitus inadequately controlled with diet and exercise.

    Science.gov (United States)

    Nauck, Michael A; Stewart, Murray W; Perkins, Christopher; Jones-Leone, Angela; Yang, Fred; Perry, Caroline; Reinhardt, Rickey R; Rendell, Marc

    2016-02-01

    Additional safe and effective therapies for type 2 diabetes are needed, especially ones that do not cause weight gain and have a low risk of hypoglycaemia. The present study evaluated albiglutide as monotherapy. In this placebo-controlled study, 309 patients (aged ≥ 18 years) with type 2 diabetes inadequately controlled by diet and exercise and who were not using a glucose-lowering agent (HbA1c 7.0-10.0% [53.00-85.79 mmol/mol], body mass index 20-45 kg/m(2), and fasting C-peptide ≥ 0.26 nmol/l) were randomised (1:1:1 on a fixed randomisation schedule using an interactive voice response system) to receive once-weekly albiglutide 30 mg (n = 102) or 50 mg (n = 102) or matching placebo (n = 105). The study treatments were blinded to both patients and study personnel. All study data were collected at individual patient clinic visits. The primary efficacy endpoint was change in HbA1c from baseline to week 52. The primary analysis was applied to the intent-to-treat population. Additional efficacy and safety endpoints were assessed. At week 52, both albiglutide 30 mg and 50 mg were superior to placebo in reducing HbA1c. The least-squares means treatment difference from placebo was -0.84% (95% CI -1.11%, -0.58%; p < 0.0001) with albiglutide 30 mg and -1.04% (-1.31%, -0.77%; p < 0.0001) with albiglutide 50 mg. Injection-site reactions were reported more frequently with albiglutide (30 mg: 17.8%; 50 mg: 22.2%) than with placebo (9.9%). Other commonly reported adverse events included nausea, diarrhoea, vomiting and hypoglycaemia; the incidences of these were generally similar across treatment groups. Albiglutide is safe and effective as monotherapy and significantly lowered HbA1c levels over 52 weeks, did not cause weight gain, and had good gastrointestinal tolerability and a low rate of hypoglycaemia compared with placebo. Trial registration ClinicalTrials.gov NCT00849017 Funding This study was sponsored by GlaxoSmithKline.

  10. Dual-purpose linker for alpha helix stabilization and imaging agent conjugation to glucagon-like peptide-1 receptor ligands.

    Science.gov (United States)

    Zhang, Liang; Navaratna, Tejas; Liao, Jianshan; Thurber, Greg M

    2015-02-18

    Peptides display many characteristics of efficient imaging agents such as rapid targeting, fast background clearance, and low non-specific cellular uptake. However, poor stability, low affinity, and loss of binding after labeling often preclude their use in vivo. Using glucagon-like peptide-1 receptor (GLP-1R) ligands exendin and GLP-1 as a model system, we designed a novel α-helix-stabilizing linker to simultaneously address these limitations. The stabilized and labeled peptides showed an increase in helicity, improved protease resistance, negligible loss or an improvement in binding affinity, and excellent in vivo targeting. The ease of incorporating azidohomoalanine in peptides and efficient reaction with the dialkyne linker enable this technique to potentially be used as a general method for labeling α helices. This strategy should be useful for imaging beta cells in diabetes research and in developing and testing other peptide targeting agents.

  11. receptores

    Directory of Open Access Journals (Sweden)

    Salete Regina Daronco Benetti

    2006-01-01

    Full Text Available Se trata de un estudio etnográfico, que tuvo lo objetivo de interpretar el sistema de conocimiento y del significado atribuidos a la sangre referente a la transfusión sanguínea por los donadores y receptores de un banco de sangre. Para la colecta de las informaciones se observaron los participantes y la entrevista etnográfica se realizó el análisis de dominio, taxonómicos y temáticos. Los dominios culturales fueron: la sangre es vida: fuente de vida y alimento valioso; creencias religiosas: fuentes simbólicas de apoyos; donación sanguínea: un gesto colaborador que exige cuidarse, gratifica y trae felicidad; donación sanguínea: fuente simbólica de inseguridad; estar enfermo es una condición para realizar transfusión sanguínea; transfusión sanguínea: esperanza de vida; Creencias populares: transfusión sanguínea como riesgo para la salud; donadores de sangre: personas benditas; donar y recibir sangre: como significado de felicidad. Temática: “líquido precioso que origina, sostiene, modifica la vida, provoca miedo e inseguridad”.

  12. HBA1C CONTROL AND COST-EFFECTIVENESS IN PATIENTS WITH TYPE 2 DIABETES MELLITUS INITIATED ON CANAGLIFLOZIN OR A GLUCAGON-LIKE PEPTIDE 1 RECEPTOR AGONIST IN A REAL-WORLD SETTING.

    Science.gov (United States)

    Wysham, Carol H; Pilon, Dominic; Ingham, Mike; Lafeuille, Marie-Hélène; Emond, Bruno; Kamstra, Rhiannon; Pfeifer, Michael; Lefebvre, Patrick

    2018-03-01

    To compare glycated hemoglobin (HbA1c) control and medication costs between patients with type 2 diabetes mellitus (T2DM) treated with canagliflozin 300 mg (CANA) or a glucagon-like peptide 1 receptor agonist (GLP-1 RA) in a real-world setting. Adults with T2DM newly initiated on CANA or a GLP-1 RA (index date) were identified from IQVIA ™ Real-World Data Electronic Medical Records U.S. database (March 29, 2012-April 30, 2016). Inverse probability of treatment weighting accounted for differences in baseline characteristics. HbA1c levels at 3-month intervals were compared using generalized estimating equations. Medication costs used wholesale acquisition costs. For both cohorts (CANA: n = 11,435; GLP-1 RA: n = 11,582), HbA1c levels decreased at 3 months postindex and remained lower through 30 months. Absolute changes in mean HbA1c from index to 3 months postindex for CANA and GLP-1 RA were -1.16% and -1.21% (patients with baseline HbA1c ≥7% [53 mmol/mol]); -1.54% and -1.51% (patients with baseline HbA1c ≥8% [64 mmol/mol]); and -2.13% and -1.99% (patients with baseline HbA1c ≥9% [75 mmol/mol]), respectively. Postindex, CANA patients with baseline HbA1c ≥7% had similar HbA1c levels at each interval versus GLP-1 RA patients, except 9 months (mean HbA1c, 7.75% [61 mmol/mol] vs. 7.86% [62 mmol/mol]; P = .0305). CANA patients with baseline HbA1c ≥8% and ≥9% had consistently lower HbA1c numerically versus GLP-1 RA patients and statistically lower HbA1c at 9 (baseline HbA1c ≥8% or ≥9%), 27, and 30 months (baseline HbA1c ≥9%). Continuous 12-month medication cost $3,326 less for CANA versus GLP-1 RA. This retrospective study demonstrated a similar evolution of HbA1c levels among CANA and GLP-1 RA patients in a real-world setting. Lower medication costs suggest CANA is economically dominant over GLP-1 RA (similar effectiveness, lower cost). AHA = antihyperglycemic agent BMI = body mass index CANA = canagliflozin 300 mg DCSI = diabetes complications severity

  13. Illuminating the Sites of Enterovirus Replication in Living Cells by Using a Split-GFP-Tagged Viral Protein

    NARCIS (Netherlands)

    van der Schaar, H M; Melia, C E; van Bruggen, J A C; Strating, J R P M; van Geenen, M E D; Koster, A J; Bárcena, M; van Kuppeveld, F J M

    2016-01-01

    Like all other positive-strand RNA viruses, enteroviruses generate new organelles (replication organelles [ROs]) with a unique protein and lipid composition on which they multiply their viral genome. Suitable tools for live-cell imaging of enterovirus ROs are currently unavailable, as recombinant

  14. Antigen Uptake during Different Life Stages of Zebrafish (Danio rerio Using a GFP-Tagged Yersinia ruckeri.

    Directory of Open Access Journals (Sweden)

    Rozalia Korbut

    Full Text Available Immersion-vaccines (bacterins are routinely used for aquacultured rainbow trout to protect against Yersinia ruckeri (Yr. During immersion vaccination, rainbow trout take up and process the antigens, which induce protection. The zebrafish was used as a model organism to study uptake mechanisms and subsequent antigen transport in fish. A genetically modified Yr was developed to constitutively express green fluorescent protein (GFP and was used for bacterin production. Larval, juvenile and adult transparent zebrafish (tra:nac mutant received a bath in the bacterin for up to 30 minutes. Samples were taken after 1 min, 15 min, 30 min, 2 h, 12 h and 24 h. At each sampling point fish were used for live imaging of the uptake using a fluorescence stereomicroscope and for immunohistochemistry (IHC. In adult fish, the bacterin could be traced within 30 min in scale pockets, skin, oesophagus, intestine and fins. Within two hours post bath (pb Yr-antigens were visible in the spleen and at 24 h in liver and kidney. Bacteria were associated with the gills, but uptake at this location was limited. Antigens were rarely detected in the blood and never in the nares. In juvenile fish uptake of the bacterin was seen in the intestine 30 min pb and in the nares 2 hpb but never in scale pockets. Antigens were detected in the spleen 12 hpb. Zebrafish larvae exhibited major Yr uptake only in the mid-intestine enterocytes 24 hpb. The different life stages of zebrafish varied with regard to uptake locations, however the gut was consistently a major uptake site. Zebrafish and rainbow trout tend to have similar uptake mechanisms following immersion or bath vaccination, which points towards zebrafish as a suitable model organism for this aquacultured species.

  15. Construction of a stable GFP-tagged Vibrio harveyi strain for bacterial dynamics analysis of abalone infection.

    Science.gov (United States)

    Travers, Marie-Agnès; Barbou, Annaïck; Le Goïc, Nelly; Huchette, Sylvain; Paillard, Christine; Koken, Marcel

    2008-12-01

    Vibrio harveyi is a bacterial marine pathogen that can cause fatal disease in a large range of vertebrates and invertebrates, including the commercially important marine gastropod, Haliotis tuberculata. Since 1997, strains of this bacterium have regularly been causing high mortalities in farmed and wild abalone populations. The way in which the pathogen enters into abalone and the disease transmission mechanisms are thus far unknown. Therefore, a pathogenic strain, ORM4, was green fluorescent protein-tagged and validated both for its growth characteristics and for its virulence as a genuine model for abalone disease. The strain allows V. harveyi quantification by flow cytometry in seawater and in abalone haemolymph as well as the in situ detection of the parasite inside abalone tissues.

  16. Antigen Uptake during Different Life Stages of Zebrafish (Danio rerio) Using a GFP-Tagged Yersinia ruckeri

    DEFF Research Database (Denmark)

    Korbut, Rozalia; Mehrdana, Foojan; Kania, Per Walter

    2016-01-01

    Immersion-vaccines (bacterins) are routinely used for aquacultured rainbow trout to protect against Yersinia ruckeri (Yr). During immersion vaccination, rainbow trout take up and process the antigens, which induce protection. The zebrafish was used as a model organism to study uptake mechanisms...... the gut was consistently a major uptake site. Zebrafish and rainbow trout tend to have similar uptake mechanisms following immersion or bath vaccination, which points towards zebrafish as a suitable model organism for this aquacultured species....

  17. Islet-selectivity of G-protein coupled receptor ligands evaluated for PET imaging of pancreatic {beta}-cell mass

    Energy Technology Data Exchange (ETDEWEB)

    Cline, Gary W., E-mail: gary.cline@yale.edu [Yale University School of Medicine (United States); Zhao, Xiaojian [Yale University School of Medicine (United States); Jakowski, Amy B.; Soeller, Walter C.; Treadway, Judith L. [Pfizer Global Research and Development, Pfizer Inc., Groton CT (United States)

    2011-09-02

    Highlights: {yields} We screened G-protein coupled receptors for imaging pancreatic. {yields} Database mining and immunohistochemistry identified GPCRs enriched in {beta}-cells. {yields} In vitro and in vivo assays were used to determine exocrine vs endocrine specificity. {yields} GPCR candidates for imaging of {beta}-cell mass are Prokineticin-1R, mGluR5, and GLP-1R. -- Abstract: A critical unmet need exists for methods to quantitatively measure endogenous pancreatic {beta}-cell mass (BCM) for the clinical evaluation of therapies to prevent or reverse loss of BCM and diabetes progression. Our objective was to identify G-protein coupled receptors (GPCRs) that are expressed with a high degree of specificity to islet {beta}-cells for receptor-targeted imaging of BCM. GPCRs enriched in pancreatic islets relative to pancreas acinar and hepatic tissue were identified using a database screen. Islet-specific expression was confirmed by human pancreas immunohistochemistry (IHC). In vitro selectivity assessment was determined from the binding and uptake of radiolabeled ligands to the rat insulinoma INS-1 832/13 cell line and isolated rat islets relative to the exocrine pancreas cell-type, PANC-1. Tail-vein injections of radioligands into rats were used to determine favorable image criteria of in vivo biodistribution to the pancreas relative to other internal organs (i.e., liver, spleen, stomach, and lungs). Database and IHC screening identified four candidate receptors for further in vitro and in vivo evaluation for PET imaging of BCM: prokineticin-1 receptor (PK-1R), metabotropic glutamate receptor type-5 (mGluR5), neuropeptide Y-2 receptor (NPY-2R), and glucagon-like peptide 1 receptor (GLP-1R). In vitro specificity ratios gave the following receptor rank order: PK-1R > GLP-1R > NPY-2R > mGluR5. The biodistribution rank order of selectivity to the pancreas was found to be PK-1R > VMAT2 {approx} GLP-1R > mGluR5. Favorable islet selectivity and biodistribution

  18. Islet-selectivity of G-protein coupled receptor ligands evaluated for PET imaging of pancreatic β-cell mass

    International Nuclear Information System (INIS)

    Cline, Gary W.; Zhao, Xiaojian; Jakowski, Amy B.; Soeller, Walter C.; Treadway, Judith L.

    2011-01-01

    Highlights: → We screened G-protein coupled receptors for imaging pancreatic. → Database mining and immunohistochemistry identified GPCRs enriched in β-cells. → In vitro and in vivo assays were used to determine exocrine vs endocrine specificity. → GPCR candidates for imaging of β-cell mass are Prokineticin-1R, mGluR5, and GLP-1R. -- Abstract: A critical unmet need exists for methods to quantitatively measure endogenous pancreatic β-cell mass (BCM) for the clinical evaluation of therapies to prevent or reverse loss of BCM and diabetes progression. Our objective was to identify G-protein coupled receptors (GPCRs) that are expressed with a high degree of specificity to islet β-cells for receptor-targeted imaging of BCM. GPCRs enriched in pancreatic islets relative to pancreas acinar and hepatic tissue were identified using a database screen. Islet-specific expression was confirmed by human pancreas immunohistochemistry (IHC). In vitro selectivity assessment was determined from the binding and uptake of radiolabeled ligands to the rat insulinoma INS-1 832/13 cell line and isolated rat islets relative to the exocrine pancreas cell-type, PANC-1. Tail-vein injections of radioligands into rats were used to determine favorable image criteria of in vivo biodistribution to the pancreas relative to other internal organs (i.e., liver, spleen, stomach, and lungs). Database and IHC screening identified four candidate receptors for further in vitro and in vivo evaluation for PET imaging of BCM: prokineticin-1 receptor (PK-1R), metabotropic glutamate receptor type-5 (mGluR5), neuropeptide Y-2 receptor (NPY-2R), and glucagon-like peptide 1 receptor (GLP-1R). In vitro specificity ratios gave the following receptor rank order: PK-1R > GLP-1R > NPY-2R > mGluR5. The biodistribution rank order of selectivity to the pancreas was found to be PK-1R > VMAT2 ∼ GLP-1R > mGluR5. Favorable islet selectivity and biodistribution characteristics suggest several GPCRs as potential

  19. Key interactions by conserved polar amino acids located at the transmembrane helical boundaries in Class B GPCRs modulate activation, effector specificity and biased signalling in the glucagon-like peptide-1 receptor

    OpenAIRE

    Wootten, Denise; Reynolds, Christopher A.; Smith, Kevin J.; Mobarec, Juan C.; Furness, Sebastian G.B.; Miller, Laurence J.; Christopoulos, Arthur; Sexton, Patrick M.

    2016-01-01

    Class B GPCRs can activate multiple signalling effectors with the potential to exhibit biased agonism in response to ligand stimulation. Previously, we highlighted key TM domain polar amino acids that were crucial for the function of the GLP-1 receptor, a key therapeutic target for diabetes and obesity. Using a combination of mutagenesis, pharmacological characterisation, mathematical and computational molecular modelling, this study identifies additional highly conserved polar residues locat...

  20. Short-acting glucagon-like peptide-1 receptor agonists as add-on to insulin therapy in type 1 diabetes

    DEFF Research Database (Denmark)

    Albèr, Anders; Brønden, Andreas; Knop, Filip K

    2017-01-01

    emptying in patients with type 1 diabetes, which could translate into effective lowering of postprandial glucose excursions; however, these observations regarding short-acting GLP-1RAs are all derived from small open-label trials and should thus be interpreted with caution. In the present paper we review......A large proportion of patients with type 1 diabetes do not reach their glycaemic target of glycated hemoglobin (HbA1c) type 1 diabetes are overweight and obese. Treatment of type 1 diabetes is based on insulin therapy......, which is associated with well-described and unfortunate adverse effects such as hypoglycaemia and increased body weight. Glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) are the focus of increasing interest as a possible adjunctive treatment to insulin in type 1 diabetes because...

  1. A Dual-Purpose Linker for Alpha Helix Stabilization and Imaging Agent Conjugation to Glucagon-Like Peptide-1 Receptor Ligands

    Science.gov (United States)

    Zhang, Liang; Navaratna, Tejas; Liao, Jianshan; Thurber, Greg M.

    2016-01-01

    Peptides display many characteristics of efficient imaging agents such as rapid targeting, fast background clearance, and low non-specific cellular uptake. However, poor stability, low affinity, and loss of binding after labeling often preclude their use in vivo. Using the glucagon-like peptide-1 receptor (GLP-1R) ligands exendin and GLP-1 as a model system, we designed a novel alpha helix stabilizing linker to simultaneously address these limitations. The stabilized and labeled peptides showed an increase in helicity, improved protease resistance, negligible loss or an improvement in binding affinity, and excellent in vivo targeting. The ease of incorporating azidohomoalanine in peptides and efficient reaction with the dialkyne linker enables this technique to potentially be used as a general method for labeling alpha helices. This strategy should be useful for imaging beta cells in diabetes research and in developing and testing other peptide targeting agents. PMID:25594741

  2. RABA Members Act in Distinct Steps of Subcellular Trafficking of the FLAGELLIN SENSING2 Receptor[W

    Science.gov (United States)

    Choi, Seung-won; Tamaki, Takayuki; Ebine, Kazuo; Uemura, Tomohiro; Ueda, Takashi; Nakano, Akihiko

    2013-01-01

    Cell surface proteins play critical roles in the perception of environmental stimuli at the plasma membrane (PM) and ensuing signal transduction. Intracellular localization of such proteins must be strictly regulated, which requires elaborate integration of exocytic and endocytic trafficking pathways. Subcellular localization of Arabidopsis thaliana FLAGELLIN SENSING2 (FLS2), a receptor that recognizes bacterial flagellin, also depends on membrane trafficking. However, our understanding about the mechanisms involved is still limited. In this study, we visualized ligand-induced endocytosis of FLS2 using green fluorescent protein (GFP)-tagged FLS2 expressed in Nicotiana benthamiana. Upon treatment with the flg22 peptide, internalized FLS2-GFP from the PM was transported to a compartment with properties intermediate between the trans-Golgi network (TGN) and the multivesicular endosome. This compartment gradually discarded the TGN characteristics as it continued along the trafficking pathway. We further found that FLS2 endocytosis involves distinct RABA/RAB11 subgroups at different steps. Moreover, we demonstrated that transport of de novo–synthesized FLS2 to the PM also involves a distinct RABA/RAB11 subgroup. Our results demonstrate the complex regulatory system for properly localizing FLS2 and functional differentiation in RABA members in endo- and exocytosis. PMID:23532067

  3. Glucagon-like peptide-1 receptor agonists compared with basal insulins for the treatment of type 2 diabetes mellitus: a systematic review and meta-analysis.

    Science.gov (United States)

    Singh, Sonal; Wright, Eugene E; Kwan, Anita Y M; Thompson, Juliette C; Syed, Iqra A; Korol, Ellen E; Waser, Nathalie A; Yu, Maria B; Juneja, Rattan

    2017-02-01

    Since 2005, several glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have been approved to treat people with type 2 diabetes. These agents are considered for use at the same point in the treatment paradigm as basal insulins. A comprehensive comparison of these drug classes, therefore, can help inform treatment decisions. This systematic review and meta-analysis assessed the clinical efficacy and safety of GLP-1 RAs compared with basal insulins. MEDLINE, EMBASE, CENTRAL and PubMed databases were searched. Randomized clinical trials (RCTs) of ≥16 weeks' duration comparing GLP-1 RAs vs basal insulins in adults with type 2 diabetes inadequately controlled with oral antihyperglycemic drugs were included. Data on the change from baseline to 26 weeks (±10 weeks) of treatment in hemoglobin A1c (HbA1c) and weight, as well as the proportion of patients experiencing hypoglycaemia, were extracted. Fixed-effect pairwise meta-analyses were conducted where data were available from ≥2 studies. Fifteen RCTs were identified and 11 were meta-analysed. The once-weekly GLP-1 RAs, exenatide long acting release (LAR) and dulaglutide, led to greater, statistically significant mean HbA1c reductions vs basal insulins (exenatide: -0.31% [95% confidence interval -0.42, -0.19], dulaglutide: -0.39% [-0.49, -0.29]) whilst once-daily liraglutide and twice-daily exenatide did not (liraglutide: 0.06% [-0.06, 0.18], exenatide: 0.01% [-0.11, 0.13]). Mean weight reduction was seen with all GLP-1 RAs while mean weight gain was seen with basal insulins. Interpretation of the analysis of hypoglycaemia was limited by inconsistent definitions and reporting. Because of the limited number of available studies sensitivity analyses to explore heterogeneity could not be conducted. Although weight reduction is seen with all GLP-1 RA's, only the once-weekly agents, exenatide LAR and dulaglutide, demonstrate significant HbA1c reductions when compared to basal insulins. © 2016 The Authors. Diabetes

  4. Reversal of obesity and insulin resistance by a non-peptidic glucagon-like peptide-1 receptor agonist in diet-induced obese mice.

    Directory of Open Access Journals (Sweden)

    Min He

    Full Text Available BACKGROUND: Glucagon-like peptide-1 (GLP-1 is recognized as an important regulator of glucose homeostasis. Efforts to utilize GLP-1 mimetics in the treatment of diabetes have yielded clinical benefits. A major hurdle for an effective oral therapy has been the difficulty of finding a non-peptidic GLP-1 receptor (GLP-1R agonist. While its oral bioavailability still poses significant challenges, Boc5, one of the first such compounds, has demonstrated the attainment of GLP-1R agonism in diabetic mice. The present work was to investigate whether subchronic Boc5 treatment can restore glycemic control and induce sustainable weight loss in diet-induced obese (DIO mice, an animal model of human obesity and insulin resistance. METHODOLOGY/PRINCIPAL FINDINGS: DIO mice were treated three times a week with Boc5 (0.3, 1 and 3 mg for 12 weeks. Body weight, body mass index (BMI, food intake, fasting glucose, intraperitoneal glucose tolerance and insulin induced glucose clearance were monitored regularly throughout the treatment. Glucose-stimulated insulin secretion, β-cell mass, islet size, body composition, serum metabolic profiles, lipogenesis, lipolysis, adipose hypertrophy and lipid deposition in the liver and muscle were also measured after 12 weeks of dosing. Boc5 dose-dependently reduced body weight, BMI and food intake in DIO mice. These changes were associated with significant decreases in fat mass, adipocyte hypertrophy and peripheral tissue lipid accumulation. Boc5 treatment also restored glycemic control through marked improvement of insulin sensitivity and normalization of β-cell mass. Administration of Boc5 (3 mg reduced basal but enhanced insulin-mediated glucose incorporation and noradrenaline-stimulated lipolysis in isolated adipocytes from obese mice. Furthermore, circulating leptin, adiponectin, triglyceride, total cholesterol, nonesterified fatty acid and high-density lipoprotein/low-density lipoprotein ratio were normalized to various

  5. Concomitant expression of several peptide receptors in neuroendocrine tumours: molecular basis for in vivo multireceptor tumour targeting

    International Nuclear Information System (INIS)

    Reubi, Jean Claude; Waser, Beatrice

    2003-01-01

    Peptide receptors have been found to represent excellent targets for in vivo cancer diagnosis and therapy. Recent in vitro studies have shown that many cancers can overexpress not only one but several peptide receptors concomitantly. One of the challenges for nuclear medicine in this field in the coming decade will be to take advantage of the co-expression of peptide receptors for multireceptor tumour targeting. In vitro receptor studies can reveal which peptide receptor is overexpressed in which tumour and which receptors are co-expressed in an individual tumour; such knowledge is a prerequisite for successful in vivo development. One group of tumours of particular interest in this respect is the neuroendocrine tumours, which have previously been shown often to express peptide receptors. This review summarises our investigations of the concomitant expression of 13 different peptide receptors, in more than 100 neuroendocrine tumours of the human intestine, pancreas and lung, using in vitro receptor autoradiography with subtype-selective ligands. The incidence and density of the somatostatin receptors sst 1 -sst 5 , the VIP receptors VPAC 1 and VPAC 2 , the CCK 1 and CCK 2 receptors, the three bombesin receptor subtypes BB 1 (NMB receptor), BB 2 (GRP receptor) and BB 3 , and GLP-1 receptors were evaluated. While the presence of VPAC 1 and sst 2 was detected in the majority of these neuroendocrine tumours, the other receptors, more differentially expressed, revealed a characteristic receptor pattern in several tumour types. Ileal carcinoids expressed sst 2 and VPAC 1 receptors in virtually all cases and had CCK 1 , CCK 2 , sst 1 or sst 5 in approximately half of the cases; they were the only tumours of this series to express NMB receptors. Insulinomas were characterised by a very high incidence of GLP-1, CCK 2 and VPAC 1 receptors, with the GLP-1 receptors expressed in a particularly high density; they expressed sst 2 in two-thirds and sst 1 in approximately half of

  6. Concomitant expression of several peptide receptors in neuroendocrine tumours: molecular basis for in vivo multireceptor tumour targeting

    Energy Technology Data Exchange (ETDEWEB)

    Reubi, Jean Claude; Waser, Beatrice [Division of Cell Biology and Experimental Cancer Research, Institute of Pathology, University of Berne, Murtenstrasse 31, PO Box 62, 3010, Berne (Switzerland)

    2003-05-01

    Peptide receptors have been found to represent excellent targets for in vivo cancer diagnosis and therapy. Recent in vitro studies have shown that many cancers can overexpress not only one but several peptide receptors concomitantly. One of the challenges for nuclear medicine in this field in the coming decade will be to take advantage of the co-expression of peptide receptors for multireceptor tumour targeting. In vitro receptor studies can reveal which peptide receptor is overexpressed in which tumour and which receptors are co-expressed in an individual tumour; such knowledge is a prerequisite for successful in vivo development. One group of tumours of particular interest in this respect is the neuroendocrine tumours, which have previously been shown often to express peptide receptors. This review summarises our investigations of the concomitant expression of 13 different peptide receptors, in more than 100 neuroendocrine tumours of the human intestine, pancreas and lung, using in vitro receptor autoradiography with subtype-selective ligands. The incidence and density of the somatostatin receptors sst{sub 1}-sst{sub 5}, the VIP receptors VPAC{sub 1} and VPAC{sub 2}, the CCK{sub 1} and CCK{sub 2} receptors, the three bombesin receptor subtypes BB{sub 1} (NMB receptor), BB{sub 2} (GRP receptor) and BB{sub 3}, and GLP-1 receptors were evaluated. While the presence of VPAC{sub 1} and sst{sub 2} was detected in the majority of these neuroendocrine tumours, the other receptors, more differentially expressed, revealed a characteristic receptor pattern in several tumour types. Ileal carcinoids expressed sst{sub 2} and VPAC{sub 1} receptors in virtually all cases and had CCK{sub 1}, CCK{sub 2}, sst{sub 1} or sst{sub 5} in approximately half of the cases; they were the only tumours of this series to express NMB receptors. Insulinomas were characterised by a very high incidence of GLP-1, CCK{sub 2} and VPAC{sub 1} receptors, with the GLP-1 receptors expressed in a

  7. A Hydrogen-Bonded Polar Network in the Core of the Glucagon-Like Peptide-1 Receptor Is a Fulcrum for Biased Agonism: Lessons from Class B Crystal Structures

    OpenAIRE

    Wootten, Denise; Reynolds, Christopher A.; Koole, Cassandra; Smith, Kevin J.; Mobarec, Juan C.; Simms, John; Quon, Tezz; Coudrat, Thomas; Furness, Sebastian G. B.; Miller, Laurence J.; Christopoulos, Arthur; Sexton, Patrick M.

    2016-01-01

    The glucagon-like peptide 1 (GLP-1) receptor is a class B G protein-coupled receptor (GPCR) that is a key target for treatments for type II diabetes and obesity. This receptor, like other class B GPCRs, displays biased agonism, though the physiologic significance of this is yet to be elucidated. Previous work has implicated R2.60190, N3.43240, Q7.49394, and H6.52363 as key residues involved in peptide-mediated biased agonism, with R2.60190, N3.43240, and Q7.49394 predicted to form a polar int...

  8. Expression of feeding-related peptide receptors mRNA in GT1-7 cell line and roles of leptin and orexins in control of GnRH secretion.

    Science.gov (United States)

    Yang, Ying; Zhou, Li-bin; Liu, Shang-quan; Tang, Jing-feng; Li, Feng-yin; Li, Rong-ying; Song, Huai-dong; Chen, Ming-dao

    2005-08-01

    To investigate the expression of feeding-related peptide receptors mRNA in GT1-7 cell line and roles of leptin and orexins in the control of GnRH secretion. Receptors of bombesin3, cholecystokinin (CCK)-A, CCK-B, glucagon-like peptide (GLP)1, melanin-concentrating hormone (MCH)1, orexin1, orexin2, neuromedin-B, neuropeptide Y (NPY)1 and NPY5, neurotensin (NT)1, NT2, NT3, and leptin receptor long form mRNA in GT1-7 cells were detected by reversed transcriptase-polymerase chain reaction. GT1-7 cells were treated with leptin, orexin A and orexin B at a cohort of concentrations for different lengths of time, and GnRH in medium was determined by radioimmunoassay (RIA). Receptors of bombesin 3, CCK-B, GLP1, MCH1, orexin1, neuromedin-B, NPY1, NPY5, NT1, NT3, and leptin receptor long form mRNA were expressed in GT1-7 cells, of which, receptors of GLP1, neuromedin-B, NPY1, and NT3 were highly expressed. No amplified fragments of orexin2, NT2, and CCK-A receptor cDNA were generated with GT1-7 RNA, indicating that the GT1-7 cells did not express mRNA of them. Leptin induced a significant stimulation of GnRH release, the results being most significant at 0.1 nmol/L for 15 min. In contrast to other studies in hypothalamic explants, neither orexin A nor orexin B affected basal GnRH secretion over a wide range of concentrations ranging from 1 nmol/L to 500 nmol/Lat 15, 30, and 60 min. Feeding and reproductive function are closely linked. Many orexigenic and anorexigenic signals may control feeding behavior as well as alter GnRH secretion through their receptors on GnRH neurons.

  9. Evaluation of 18F-labeled exendin(9-39) derivatives targeting glucagon-like peptide-1 receptor for pancreatic β-cell imaging.

    Science.gov (United States)

    Kimura, Hiroyuki; Ogawa, Yu; Fujimoto, Hiroyuki; Mukai, Eri; Kawashima, Hidekazu; Arimitsu, Kenji; Toyoda, Kentaro; Fujita, Naotaka; Yagi, Yusuke; Hamamatsu, Keita; Murakami, Takaaki; Murakami, Atsushi; Ono, Masahiro; Nakamoto, Yuji; Togashi, Kaori; Inagaki, Nobuya; Saji, Hideo

    2018-01-15

    β-cell mass (BCM) is known to be decreased in subjects with type-2 diabetes (T2D). Quantitative analysis for BCM would be useful for understanding how T2D progresses and how BCM affects treatment efficacy and for earlier diagnosis of T2D and development of new therapeutic strategies. However, a noninvasive method to measure BCM has not yet been developed. We developed four 18 F-labeled exendin(9-39) derivatives for β-cell imaging by PET: [ 18 F]FB9-Ex(9-39), [ 18 F]FB12-Ex(9-39), [ 18 F]FB27-Ex(9-39), and [ 18 F]FB40-Ex(9-39). Affinity to the glucagon-like peptide-1 receptor (GLP-1R) was evaluated with dispersed islet cells of ddY mice. Uptake of exendin(9-39) derivatives in the pancreas as well as in other organs was evaluated by a biodistribution study. Small-animal PET study was performed after injecting [ 18 F]FB40-Ex(9-39). FB40-Ex(9-39) showed moderate affinity to the GLP-1R. Among all of the derivatives, [ 18 F]FB40-Ex(9-39) resulted in the highest uptake of radioactivity in the pancreas 30 min after injection. Moreover, it showed significantly less radioactivity accumulated in the liver and kidney, resulting in an overall increase in the pancreas-to-organ ratio. In the PET imaging study, pancreas was visualized at 30 min after injection of [ 18 F]FB40-Ex(9-39). [ 18 F]FB40-Ex(9-39) met the basic requirements for an imaging probe for GLP-1R in pancreatic β-cells. Further enhancement of pancreatic uptake and specific binding to GLP-1R will lead to a clear visualization of pancreatic β-cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Non-invasive glucagon-like peptide-1 receptor imaging in pancreas with {sup 18}F-Al labeled Cys{sup 39}-exendin-4

    Energy Technology Data Exchange (ETDEWEB)

    Mi, Baoming [Department of Nuclear Medicine, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, 215006 (China); Department of Nuclear Medicine, Affiliated Hospital of Jiangnan University (Wuxi 4th People' s Hospital), Wuxi, Jiangsu, 214062 (China); Xu, Yuping [Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, 214063 (China); Nanjing Medical University, Nanjing, Jiangsu, 210029 (China); Pan, Donghui; Wang, Lizhen; Yang, Runlin [Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, 214063 (China); Yu, Chunjing; Wan, Weixing [Department of Nuclear Medicine, Affiliated Hospital of Jiangnan University (Wuxi 4th People' s Hospital), Wuxi, Jiangsu, 214062 (China); Wu, Yiwei, E-mail: wuyiwei3988@gmail.com [Department of Nuclear Medicine, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, 215006 (China); Yang, Min, E-mail: ymzfk@yahoo.com.hk [Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, 214063 (China); Nanjing Medical University, Nanjing, Jiangsu, 210029 (China)

    2016-02-26

    Purpose: Glucagon-like peptide-1 receptor (GLP-1R) is abundantly expressed on beta cells and may be an ideal target for the pancreas imaging. Monitoring the GLP-1R of pancreas could be benefit for understanding the pathophysiology of diabetes. In the present study, {sup 18}F-Al labeled exendin-4 analog, {sup 18}F-Al-NOTA-MAL-Cys{sup 39}-exendin-4, was evaluated for PET imaging GLP-1R in the pancreas. Methods: The targeting of {sup 18}F-Al labeled exendin-4 analog was examined in healthy and streptozotocin induced diabetic rats. Rats were injected with {sup 18}F-Al-NOTA-MAL-Cys{sup 39}-exendin-4 and microPET imaging was performed at 1 h postinjection, followed by ex vivo biodistribution. GLP-1R expression in pancreas was determined through post mortern examinations. Results: The pancreas of healthy rats was readily visualized after administration of {sup 18}F-Al-NOTA-MAL-Cys{sup 39}-exendin-4, whereas the pancreas of diabetic rats, as well as those from rats co-injected with excess of unlabeled peptides, was barely visible by microPET. At 60 min postinjection, the pancreatic uptakes were 1.02 ± 0.15%ID/g and 0.23 ± 0.05%ID/g in healthy and diabetic rats respectively. Under block, the pancreatic uptakes of non-diabetic rats reduced to 0.21 ± 0.07%ID/g at the same time point. Biodistribution data and IHC staining confirmed the findings of the microPET imaging. Conclusion: The favorable preclinical data indicated that {sup 18}F-Al-NOTA-MAL-Cys{sup 39}-exendin-4may be suitable for non-invasive monitoring functional pancreatic beta cells.

  11. Non-invasive glucagon-like peptide-1 receptor imaging in pancreas with (18)F-Al labeled Cys(39)-exendin-4.

    Science.gov (United States)

    Mi, Baoming; Xu, Yuping; Pan, Donghui; Wang, Lizhen; Yang, Runlin; Yu, Chunjing; Wan, Weixing; Wu, Yiwei; Yang, Min

    2016-02-26

    Glucagon-like peptide-1 receptor (GLP-1R) is abundantly expressed on beta cells and may be an ideal target for the pancreas imaging. Monitoring the GLP-1R of pancreas could be benefit for understanding the pathophysiology of diabetes. In the present study, (18)F-Al labeled exendin-4 analog, (18)F-Al-NOTA-MAL-Cys(39)-exendin-4, was evaluated for PET imaging GLP-1R in the pancreas. The targeting of (18)F-Al labeled exendin-4 analog was examined in healthy and streptozotocin induced diabetic rats. Rats were injected with (18)F-Al-NOTA-MAL-Cys(39)-exendin-4 and microPET imaging was performed at 1 h postinjection, followed by ex vivo biodistribution. GLP-1R expression in pancreas was determined through post mortern examinations. The pancreas of healthy rats was readily visualized after administration of (18)F-Al-NOTA-MAL-Cys(39)-exendin-4, whereas the pancreas of diabetic rats, as well as those from rats co-injected with excess of unlabeled peptides, was barely visible by microPET. At 60 min postinjection, the pancreatic uptakes were 1.02 ± 0.15%ID/g and 0.23 ± 0.05%ID/g in healthy and diabetic rats respectively. Under block, the pancreatic uptakes of non-diabetic rats reduced to 0.21 ± 0.07%ID/g at the same time point. Biodistribution data and IHC staining confirmed the findings of the microPET imaging. The favorable preclinical data indicated that (18)F-Al-NOTA-MAL-Cys(39)-exendin-4may be suitable for non-invasive monitoring functional pancreatic beta cells. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Receptors and effects of gut hormones in three osteoblastic cell lines

    Directory of Open Access Journals (Sweden)

    Wilson Peter JM

    2011-07-01

    Full Text Available Abstract Background In recent years the interest on the relationship of gut hormones to bone processes has increased and represents one of the most interesting aspects in skeletal research. The proportion of bone mass to soft tissue is a relationship that seems to be controlled by delicate and subtle regulations that imply "cross-talks" between the nutrient intake and tissues like fat. Thus, recognition of the mechanisms that integrate a gastrointestinal-fat-bone axis and its application to several aspects of human health is vital for improving treatments related to bone diseases. This work analysed the effects of gut hormones in cell cultures of three osteoblastic cell lines which represent different stages in osteoblastic development. Also, this is the first time that there is a report on the direct effects of glucagon-like peptide 2, and obestatin on osteoblast-like cells. Methods mRNA expression levels of five gut hormone receptors (glucose-dependent insulinotropic peptide [GIP], glucagon-like peptide 1 [GLP-1], glucagon-like peptide 2 [GLP-2], ghrelin [GHR] and obestatin [OB] were analysed in three osteoblastic cell lines (Saos-2, TE-85 and MG-63 showing different stages of osteoblast development using reverse transcription and real time polymerase chain reaction. The responses to the gut peptides were studied using assays for cell viability, and biochemical bone markers: alkaline phosphatase (ALP, procollagen type 1 amino-terminal propeptides (P1NP, and osteocalcin production. Results The gut hormone receptor mRNA displayed the highest levels for GIP in Saos-2 and the lowest levels in MG-63, whereas GHR and GPR39 (the putative obestatin receptor expression was higher in TE-85 and MG-63 and lower in Saos-2. GLP-1 and GLP-2 were expressed only in MG-63 and TE-85. Treatment of gut hormones to cell lines showed differential responses: higher levels in cell viability in Saos-2 after GIP, in TE-85 and MG-63 after GLP-1, GLP-2, ghrelin and

  13. Key interactions by conserved polar amino acids located at the transmembrane helical boundaries in Class B GPCRs modulate activation, effector specificity and biased signalling in the glucagon-like peptide-1 receptor.

    Science.gov (United States)

    Wootten, Denise; Reynolds, Christopher A; Smith, Kevin J; Mobarec, Juan C; Furness, Sebastian G B; Miller, Laurence J; Christopoulos, Arthur; Sexton, Patrick M

    2016-10-15

    Class B GPCRs can activate multiple signalling effectors with the potential to exhibit biased agonism in response to ligand stimulation. Previously, we highlighted key TM domain polar amino acids that were crucial for the function of the GLP-1 receptor, a key therapeutic target for diabetes and obesity. Using a combination of mutagenesis, pharmacological characterisation, mathematical and computational molecular modelling, this study identifies additional highly conserved polar residues located towards the TM helical boundaries of Class B GPCRs that are important for GLP-1 receptor stability and/or controlling signalling specificity and biased agonism. This includes (i) three positively charged residues (R3.30 227 , K4.64 288 , R5.40 310 ) located at the extracellular boundaries of TMs 3, 4 and 5 that are predicted in molecular models to stabilise extracellular loop 2, a crucial domain for ligand affinity and receptor activation; (ii) a predicted hydrogen bond network between residues located in TMs 2 (R2.46 176 ), 6 (R6.37 348 ) and 7 (N7.61 406 and E7.63 408 ) at the cytoplasmic face of the receptor that is important for stabilising the inactive receptor and directing signalling specificity, (iii) residues at the bottom of TM 5 (R5.56 326 ) and TM6 (K6.35 346 and K6.40 351 ) that are crucial for receptor activation and downstream signalling; (iv) residues predicted to be involved in stabilisation of TM4 (N2.52 182 and Y3.52 250 ) that also influence cell signalling. Collectively, this work expands our understanding of peptide-mediated signalling by the GLP-1 receptor. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  14. Adjunctive Role of Glucagon-Like Peptide-1 Receptor Agonists in the Management of Type 1 Diabetes Mellitus.

    Science.gov (United States)

    Harris, Kira B; Boland, Cassie L

    2016-09-01

    Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are commonly used in combination with insulin to manage type 2 diabetes mellitus, and four agents are currently approved for this indication: exenatide, liraglutide, dulaglutide, and albiglutide. The distinctive properties of GLP-1 RAs-potential hemoglobin A1c (A1C) reduction, weight loss, potential to reduce insulin doses, and lower hypoglycemia risk-have made these agents potential treatment options for patients with type 1 diabetes mellitus (T1DM) as well. These positive effects are due to glucose-dependent insulin secretion, reduced glucagon secretion, increased satiety, and delayed gastric emptying. Patients with T1DM are unable to suppress glucagon during meals, which contributes to postprandial hyperglycemia and may be improved with GLP-1 therapy. In this review, we evaluated the available literature on the clinical efficacy and safety of GLP-1 RAs in patients with T1DM. We conducted a search of the PubMed (1966-May 2016) and Ovid (1946-May 2016) databases. Abstracts presented at the scientific and clinical sessions of the American Diabetes Association and the American Association of Clinical Endocrinologists were also searched. The references of the published articles were also reviewed to identify additional studies appropriate for inclusion. All identified articles published in English were evaluated. Studies were included if they evaluated the clinical use or safety of GLP-1 RAs in patients with T1DM. Twelve studies were included, with four evaluating exenatide, one evaluating exenatide extended release, and seven evaluating liraglutide. Both exenatide and liraglutide showed significant reductions in hemoglobin A1C, plasma glucose concentration, body weight, and insulin doses when administered to patients with T1DM already receiving insulin therapy, without increasing the occurrence of hypoglycemia. Adverse effects were mostly gastrointestinal in nature but were mild and transient. Patients who may

  15. Autoantibodies against Muscarinic Type 3 Receptor in Sjögren's Syndrome Inhibit Aquaporin 5 Trafficking

    Science.gov (United States)

    Lee, Byung Ha; Gauna, Adrienne E.; Perez, Geidys; Park, Yun-jong; Pauley, Kaleb M.; Kawai, Toshihisa; Cha, Seunghee

    2013-01-01

    Sjögren's syndrome (SjS) is a chronic autoimmune disease that mainly targets the salivary and lacrimal glands. It has been controversial whether anti-muscarinic type 3 receptor (α-M3R) autoantibodies in patients with SjS inhibit intracellular trafficking of aquaporin-5 (AQP5), water transport protein, leading to secretory dysfunction. To address this issue, GFP-tagged human AQP5 was overexpressed in human salivary gland cells (HSG-hAQP5) and monitored AQP5 trafficking to the plasma membrane following carbachol (CCh, M3R agonist) stimulation. AQP5 trafficking was indeed mediated by M3R stimulation, shown in partial blockage of trafficking by M3R-antagonist 4-DAMP. HSG-hAQP5 pre-incubated with SjS plasma for 24 hours significantly reduced AQP5 trafficking with CCh, compared with HSG-hAQP5 pre-incubated with healthy control (HC) plasma. This inhibition was confirmed by monoclonal α-M3R antibody and pre-absorbed plasma. Interestingly, HSG-hAQP5 pre-incubated with SjS plasma showed no change in cell volume, compared to the cells incubated with HC plasma showing shrinkage by twenty percent after CCh-stimulation. Our findings clearly indicate that binding of anti-M3R autoantibodies to the receptor, which was verified by immunoprecipitation, suppresses AQP5 trafficking to the membrane and contribute to impaired fluid secretion in SjS. Our current study urges further investigations of clinical associations between SjS symptoms, such as degree of secretory dysfunction, cognitive impairment, and/or bladder irritation, and different profiles (titers, isotypes, and/or specificity) of anti-M3R autoantibodies in individuals with SjS. PMID:23382834

  16. Patients with Obesity Caused by Melanocortin-4 Receptor Mutations Can Be Treated with a Glucagon-like Peptide-1 Receptor Agonist

    DEFF Research Database (Denmark)

    Iepsen, Eva W; Zhang, Jinyi; Thomsen, Henrik S

    2018-01-01

    Pathogenic mutations in the appetite-regulating melanocortin-4 receptor (MC4R) represent the most common cause of monogenic obesity with limited treatment options. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) cause weight loss by reducing appetite. We assessed the effect of the GLP-1 RA...... liraglutide 3.0 mg for 16 weeks in 14 obese individuals with pathogenic MC4R mutations (BMI 37.5 ± 6.8) and 28 matched control participants without MC4R mutation (BMI 36.8 ± 4.8). Liraglutide decreased body weight by 6.8 kg ± 1.8 kg in individuals with pathogenic MC4R mutations and by 6.1 kg ± 1.2 kg...... in control participants. Total body fat, waist circumference, and fasting and postprandial glucose concentrations similarly decreased in both groups. Thus, liraglutide induced an equal, clinically significant weight loss of 6% in both groups, indicating that the appetite-reducing effect of liraglutide...

  17. Utilization Patterns of Glucagon-Like Peptide-1 Receptor Agonists in Patients with Type 2 Diabetes Mellitus in Italy: A Retrospective Cohort Study.

    Science.gov (United States)

    Federici, Marco Orsini; McQuillan, Janette; Biricolti, Giovanni; Losi, Serena; Lebrec, Jeremie; Richards, Catrina; Miglio, Cristiana; Norrbacka, Kirsi

    2018-04-01

    Real-world evidence on glucagon-like peptide-1 receptor agonist (GLP-1 RAs) usage is emerging in different European countries but is lacking in Italy. This retrospective cohort study aimed to describe the real-world drug utilization patterns in patients initiating GLP-1 RAs for treating T2DM in Italy. Adults aged ≥ 20 years and with ≥ 1 oral antidiabetic drug (alone or in combination with insulin) other than GLP-1 RAs in the 6 months prior to initiating exenatide twice daily (exBID), exenatide once weekly (exQW), dulaglutide once weekly (DULA), liraglutide once daily (LIRA) or lixisenatide once daily (LIXI) between March and July 2016 were retrospectively identified in the Italian IMS LifeLink™ longitudinal prescriptions database (retail pharmacy data). Patients with ≥ 6-month follow-up (defined as evidence of any prescription activity) were included. Proportions of patients who remained persistent (continued treatment until discontinuation/switch) in the first 6 months and of those who discontinued or switched to a different GLP-1 RA over the entire follow-up were recorded. For each treatment, the average daily/weekly dosage (ADD/AWD) while persistent during the available follow-up was calculated. We identified 7319 patients: 92 exBID, 970 exQW, 3368 DULA, 2573 LIRA and 316 LIXI. Across treatments, 89% patients were ≥ 50 years old, 54% were males, and the median follow-up duration ranged between 8.1 and 8.7 months. At 6 months, 35% exBID, 47% exQW, 62% DULA, 50% LIRA and 40% LIXI patients remained persistent. Over the entire follow-up, median persistence days varied from 73 (exBID) to > 300 days (DULA). The mean ± SD ADD/AWD was exBID: 17.7 ± 2.1 µg/day; exQW: 2.1 ± 0.1 mg/week; DULA: 1.5 ± 0.2 mg/week; LIRA: 1.5 ± 0.2 mg/day; LIXI: 21.0 ± 5.5 µg/day. This real-world analysis suggests differences exist in persistence between patients treated with various GLP-1 RAs. Among the investigated

  18. Neuroendocrine response to GABA-B receptor agonism in alcohol-dependent individuals: Results from a combined outpatient and human laboratory experiment.

    Science.gov (United States)

    Farokhnia, Mehdi; Sheskier, Mikela B; Lee, Mary R; Le, April N; Singley, Erick; Bouhlal, Sofia; Ton, Timmy; Zhao, Zhen; Leggio, Lorenzo

    2018-04-14

    Gamma-aminobutyric acid (GABA), the main inhibitory neurotransmitter in the nervous system, plays an important role in biobehavioral processes that regulate alcohol seeking, food intake, and stress response. The metabotropic GABA-B receptor has been investigated as a potential therapeutic target for alcohol use disorder, by using orthosteric agonists (e.g., baclofen) and positive allosteric modulators. Whether and how pharmacological manipulation of the GABA-B receptor, in combination with alcohol intake, may affect feeding- and stress-related neuroendocrine pathways remains unknown. In the present randomized, double-blind, placebo-controlled study, thirty-four alcohol-dependent individuals received baclofen (30 mg/day) or placebo in a naturalistic outpatient setting for one week, and then performed a controlled laboratory experiment which included alcohol cue-reactivity, fixed-dose priming, and self-administration procedures. Blood samples were collected, and the following neuroendocrine markers were measured: ghrelin, leptin, amylin, glucagon-like peptide-1 (GLP-1), insulin, prolactin, thyroid-stimulating hormone, growth hormone, cortisol, and adrenocorticotropic hormone (ACTH). During the outpatient phase, baclofen significantly increased blood concentrations of acyl-ghrelin (p = 0.01), leptin (p = 0.01), amylin (p = 0.004), and GLP-1 (p = 0.02). Significant drug × time-point interaction effects for amylin (p = 0.001) and insulin (p = 0.03), and trend-level interaction effects for GLP-1 (p = 0.06) and ACTH (p = 0.10) were found during the laboratory experiment. Baclofen, compared to placebo, had no effect on alcohol drinking in this study (p's ≥ 0.05). Together with previous studies, these findings shed light on the role of the GABAergic system and GABA-B receptors in the shared neurobiology of alcohol-, feeding-, and stress-related behaviors. Copyright © 2018. Published by Elsevier Ltd.

  19. Ligands specify estrogen receptor alpha nuclear localization and degradation

    Directory of Open Access Journals (Sweden)

    Caze-Subra Stéphanie

    2010-12-01

    Full Text Available Abstract Background The estrogen receptor alpha (ERα is found predominately in the nucleus, both in hormone stimulated and untreated cells. Intracellular distribution of the ERα changes in the presence of agonists but the impact of different antiestrogens on the fate of ERα is a matter of debate. Results A MCF-7 cell line stably expressing GFP-tagged human ERα (SK19 cell line was created to examine the localization of ligand-bound GFP-ERα. We combined digitonin-based cell fractionation analyses with fluorescence and immuno-electron microscopy to determine the intracellular distribution of ligand-bound ERα and/or GFP-ERα. Using fluorescence- and electron microscopy we demonstrate that both endogenous ERα and GFP-ERα form numerous nuclear focal accumulations upon addition of agonist, 17β-estradiol (E2, and pure antagonists (selective estrogen regulator disruptor; SERD, ICI 182,780 or RU58,668, while in the presence of partial antagonists (selective estrogen regulator modulator; SERM, 4-hydroxytamoxifen (OHT or RU39,411, diffuse nuclear staining persisted. Digitonin based cell fractionation analyses confirmed that endogenous ERα and GFP-ERα predominantly reside in the nuclear fraction. Overall ERα protein levels were reduced after estradiol treatment. In the presence of SERMs ERα was stabilized in the nuclear soluble fraction, while in the presence of SERDs protein levels decreased drastically and the remaining ERα was largely found in a nuclear insoluble fraction. mRNA levels of ESR1 were reduced compared to untreated cells in the presence of all ligands tested, including E2. E2 and SERDs induced ERα degradation occurred in distinct nuclear foci composed of ERα and the proteasome providing a simple explanation for ERα sequestration in the nucleus. Conclusions Our results indicate that chemical structure of ligands directly affect the nuclear fate and protein turnover of the estrogen receptor alpha independently of their impact on

  20. Modulation of β-catenin signaling by glucagon receptor activation.

    Directory of Open Access Journals (Sweden)

    Jiyuan Ke

    Full Text Available The glucagon receptor (GCGR is a member of the class B G protein-coupled receptor family. Activation of GCGR by glucagon leads to increased glucose production by the liver. Thus, glucagon is a key component of glucose homeostasis by counteracting the effect of insulin. In this report, we found that in addition to activation of the classic cAMP/protein kinase A (PKA pathway, activation of GCGR also induced β-catenin stabilization and activated β-catenin-mediated transcription. Activation of β-catenin signaling was PKA-dependent, consistent with previous reports on the parathyroid hormone receptor type 1 (PTH1R and glucagon-like peptide 1 (GLP-1R receptors. Since low-density-lipoprotein receptor-related protein 5 (Lrp5 is an essential co-receptor required for Wnt protein mediated β-catenin signaling, we examined the role of Lrp5 in glucagon-induced β-catenin signaling. Cotransfection with Lrp5 enhanced the glucagon-induced β-catenin stabilization and TCF promoter-mediated transcription. Inhibiting Lrp5/6 function using Dickkopf-1(DKK1 or by expression of the Lrp5 extracellular domain blocked glucagon-induced β-catenin signaling. Furthermore, we showed that Lrp5 physically interacted with GCGR by immunoprecipitation and bioluminescence resonance energy transfer assays. Together, these results reveal an unexpected crosstalk between glucagon and β-catenin signaling, and may help to explain the metabolic phenotypes of Lrp5/6 mutations.

  1. A Hydrogen-Bonded Polar Network in the Core of the Glucagon-Like Peptide-1 Receptor Is a Fulcrum for Biased Agonism: Lessons from Class B Crystal Structures.

    Science.gov (United States)

    Wootten, Denise; Reynolds, Christopher A; Koole, Cassandra; Smith, Kevin J; Mobarec, Juan C; Simms, John; Quon, Tezz; Coudrat, Thomas; Furness, Sebas