scholarly journals Peripheral and Central GLP-1 Receptor Populations Mediate the Anorectic Effects of Peripherally Administered GLP-1 Receptor Agonists, Liraglutide and Exendin-4

Endocrinology ◽  
2011 ◽  
Vol 152 (8) ◽  
pp. 3103-3112 ◽  
Author(s):  
Scott E. Kanoski ◽  
Samantha M. Fortin ◽  
Myrtha Arnold ◽  
Harvey J. Grill ◽  
Matthew R. Hayes

The long-acting glucagon-like peptide-1 receptor (GLP-1R) agonists, exendin-4 and liraglutide, suppress food intake and body weight. The mediating site(s) of action for the anorectic effects produced by peripheral administration of these GLP-1R agonists are not known. Experiments addressed whether food intake suppression after ip delivery of exendin-4 and liraglutide is mediated exclusively by peripheral GLP-1R or also involves direct central nervous system (CNS) GLP-1R activation. Results showed that CNS delivery [third intracerebroventricular (3rd ICV)] of the GLP-1R antagonist exendin-(9–39) (100 μg), attenuated the intake suppression by ip liraglutide (10 μg) and exendin-4 (3 μg), particularly at 6 h and 24 h. Control experiments show that these findings appear to be based neither on the GLP-1R antagonist acting as a nonspecific competing orexigenic signal nor on blockade of peripheral GLP-1R via efflux of exendin-(9–39) to the periphery. To assess the contribution of GLP-1R expressed on subdiaphragmatic vagal afferents to the anorectic effects of liraglutide and exendin-4, food intake was compared in rats with complete subdiaphragmatic vagal deafferentation and surgical controls after ip delivery of the agonists. Both liraglutide and exendin-4 suppressed food intake at 3 h, 6 h, and 24 h for controls; for subdiaphragmatic vagal deafferentation rats higher doses of the GLP-1R agonists were needed for significant food intake suppression, which was observed at 6 h and 24 h after liraglutide and at 24 h after exendin-4. Conclusion: Food intake suppression after peripheral administration of exendin-4 and liraglutide is mediated by activation of GLP-1R expressed on vagal afferents as well as direct CNS GLP-1R activation.

2014 ◽  
Vol 92 (12) ◽  
pp. 975-983 ◽  
Author(s):  
Kartikkumar Navinchandra Patel ◽  
Amit Arvind Joharapurkar ◽  
Vishal Patel ◽  
Samadhan Govind Kshirsagar ◽  
Rajesh Bahekar ◽  
...  

Cannabinoid 1 (CB1) receptor antagonists reduce body weight and improve insulin sensitivity. Preclinical data indicates that an acute dose of CB1 antagonist rimonabant causes an increase in blood glucose. A stable analog of glucagon-like peptide 1 (GLP-1), exendin-4 improves glucose-stimulated insulin secretion in pancreas, and reduces appetite through activation of GLP-1 receptors in the central nervous system and liver. We hypothesized that the insulin secretagogue effect of GLP-1 agonist exendin-4 may synergize with the insulin-sensitizing action of rimonabant. Intraperitoneal as well as intracerebroventricular administration of rimonabant increased serum glucose upon glucose challenge in overnight fasted, diet-induced obese C57 mice, with concomitant rise in serum glucagon levels. Exendin-4 reversed the acute hyperglycemia induced by rimonabant. The combination of exendin-4 and rimonabant showed an additive effect in the food intake, and sustained body weight reduction upon repeated dosing. The acute efficacy of both the compounds was additive for inducing nausea-like symptoms in conditioned aversion test in mice, whereas exendin-4 treatment antagonized the effect of rimonabant on forced swim test upon chronic dosing. Thus, the addition of exendin-4 to rimonabant produces greater reduction in food intake owing to increased aversion, but reduces the other central nervous system side effects of rimonabant. The hyperglucagonemia induced by rimonabant is partially responsible for enhancing the antiobesity effect of exendin-4.


2012 ◽  
Vol 58 (3) ◽  
pp. 51-55
Author(s):  
E N Ostroukhova ◽  
O K Khmel'nitskiĭ ◽  
E I Krasil'nikova ◽  
K S Davidenko

This paper reports the results of the treatment of 71 patients presenting with type 2 diabetes mellitus using liraglutide, a long-acting analog of glucagon-like peptide-1 (GLP-1) marketed under the brand name Victoza. Practically all the patients experienced either improvement or normalization of the parameters of carbohydrate metabolism in conjunction with a reduction of their body weight and arterial pressure. There were no severe hypoglycemic episodes and other adverse reactions to the therapy. It is recommended that Victoza should be more widely used for the treatment of the patients with type 2 diabetes mellitus.


2011 ◽  
Vol 301 (5) ◽  
pp. R1479-R1485 ◽  
Author(s):  
Matthew R. Hayes ◽  
Scott E. Kanoski ◽  
Bart C. De Jonghe ◽  
Theresa M. Leichner ◽  
Amber L. Alhadeff ◽  
...  

The incretin and food intake suppressive effects of intraperitoneally administered glucagon-like peptide-1 (GLP-1) involve activation of GLP-1 receptors (GLP-1R) expressed on vagal afferent fiber terminals. Central nervous system processing of GLP-1R-driven vagal afferents results in satiation signaling and enhanced insulin secretion from pancreatic-projecting vagal efferents. As the vast majority of endogenous GLP-1 is released from intestinal l-cells following ingestion, it stands to reason that paracrine GLP-1 signaling, activating adjacent GLP-1R expressed on vagal afferent fibers of gastrointestinal origin, contributes to glycemic and food intake control. However, systemic GLP-1R-mediated control of glycemia is currently attributed to endocrine action involving GLP-1R expressed in the hepatoportal bed on terminals of the common hepatic branch of the vagus (CHB). Here, we examine the hypothesis that activation of GLP-1R expressed on the CHB is not required for GLP-1's glycemic and intake suppressive effects, but rather paracrine signaling on non-CHB vagal afferents is required to mediate GLP-1's effects. Selective CHB ablation (CHBX), complete subdiaphragmatic vagal deafferentation (SDA), and surgical control rats received an oral glucose tolerance test (2.0 g glucose/kg) 10 min after an intraperitoneal injection of the GLP-1R antagonist, exendin-(9–39) (Ex-9; 0.5 mg/kg) or vehicle. CHBX and control rats showed comparable increases in blood glucose following blockade of GLP-1R by Ex-9, whereas SDA rats failed to show a GLP-1R-mediated incretin response. Furthermore, GLP-1(7–36) (0.5 mg/kg ip) produced a comparable suppression of 1-h 25% glucose intake in both CHBX and control rats, whereas intake suppression in SDA rats was blunted. These findings support the hypothesis that systemic GLP-1R mediation of glycemic control and food intake suppression involves paracrine-like signaling on GLP-1R expressed on vagal afferent fibers of gastrointestinal origin but does not require the CHB.


2002 ◽  
Vol 440 (2-3) ◽  
pp. 269-279 ◽  
Author(s):  
Juris J. Meier ◽  
Baptist Gallwitz ◽  
Wolfgang E. Schmidt ◽  
Michael A. Nauck

2015 ◽  
Vol 35 (5) ◽  
pp. 1092-1100 ◽  
Author(s):  
Sarah Farr ◽  
Christopher Baker ◽  
Mark Naples ◽  
Jennifer Taher ◽  
Jahangir Iqbal ◽  
...  

1985 ◽  
Vol 42 (5) ◽  
pp. 1063-1071 ◽  
Author(s):  
S C Woods ◽  
D Porte ◽  
E Bobbioni ◽  
E Ionescu ◽  
J F Sauter ◽  
...  

Endocrinology ◽  
1999 ◽  
Vol 140 (1) ◽  
pp. 244-250 ◽  
Author(s):  
Karim Meeran ◽  
Donal O’Shea ◽  
C. Mark B. Edwards ◽  
Mandy D. Turton ◽  
Melanie M. Heath ◽  
...  

Abstract Central nervous system glucagon-like peptide-1-(7–36) amide (GLP-1) administration has been reported to acutely reduce food intake in the rat. We here report that repeated intracerebroventricular (icv) injection of GLP-1 or the GLP-1 receptor antagonist, exendin-(9–39), affects food intake and body weight. Daily icv injection of 3 nmol GLP-1 to schedule-fed rats for 6 days caused a reduction in food intake and a decrease in body weight of 16 ± 5 g (P < 0.02 compared with saline-injected controls). Daily icv administration of 30 nmol exendin-(9–39) to schedule-fed rats for 3 days caused an increase in food intake and increased body weight by 7 ± 2 g (P < 0.02 compared with saline-injected controls). Twice daily icv injections of 30 nmol exendin-(9–39) with 2.4 nmol neuropeptide Y to ad libitum-fed rats for 8 days increased food intake and increased body weight by 28 ± 4 g compared with 14 ± 3 g in neuropeptide Y-injected controls (P < 0.02). There was no evidence of tachyphylaxis in response to icv GLP-1 or exendin-(9–39). GLP-1 may thus be involved in the regulation of body weight in the rat.


2016 ◽  
Vol 311 (1) ◽  
pp. R115-R123 ◽  
Author(s):  
Fredrik Anesten ◽  
Marie K. Holt ◽  
Erik Schéle ◽  
Vilborg Pálsdóttir ◽  
Frank Reimann ◽  
...  

Neuronal circuits in the hypothalamus and hindbrain are of importance for control of food intake, energy expenditure, and fat mass. We have recently shown that treatment with exendin-4 (Ex-4), an analog of the proglucagon-derived molecule glucagon-like peptide 1 (GLP-1), markedly increases mRNA expression of the cytokine interleukin-6 (IL-6) in the hypothalamus and hindbrain and that this increase partly mediates the suppression of food intake and body weight by Ex-4. Endogenous GLP-1 in the central nervous system (CNS) is produced by preproglucagon (PPG) neurons of the nucleus of the solitary tract (NTS) in the hindbrain. These neurons project to various parts of the brain, including the hypothalamus. Outside the brain, IL-6 stimulates GLP-1 secretion from the gut and pancreas. In this study, we aim to investigate whether IL-6 can affect GLP-1-producing PPG neurons in the nucleus of the solitary tract (NTS) in mouse hindbrain via the ligand binding part of the IL-6 receptor, IL-6 receptor-α (IL-6Rα). Using immunohistochemistry, we found that IL-6Rα was localized on PPG neurons of the NTS. Recordings of these neurons in GCaMP3/GLP-1 reporter mice showed that IL-6 enhances cytosolic Ca2+ concentration in neurons capable of expressing PPG. We also show that the Ca2+ increase originates from the extracellular space. Furthermore, we found that IL-6Rα was localized on cells in the caudal hindbrain expressing immunoreactive NeuN (a neuronal marker) or CNP:ase (an oligodendrocyte marker). In summary, IL-6Rα is present on PPG neurons in the NTS, and IL-6 can stimulate these cells by increasing influx of Ca2+ to the cytosol from the extracellular space.


Diabetes ◽  
2008 ◽  
Vol 57 (10) ◽  
pp. 2603-2612 ◽  
Author(s):  
C. Knauf ◽  
P. D. Cani ◽  
D.-H. Kim ◽  
M. A. Iglesias ◽  
C. Chabo ◽  
...  

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