exendin-(9-39) and Vomiting

Exogenous glucagon-like peptide-1 (GLP-1) inhibits eating in healthy, overweight, and diabetic subjects.. The GLP-1 receptor antagonist exendin(9-39)NH2 (ex9-39) was used to further explore the role of GLP-1 as an endogenous satiation signal.. Two double-blind, 4-way crossover studies were performed, each of which included 10 healthy men. In study A, subjects received an intravenous infusion of ex9-39 or saline plus an oral glucose preload and an intraduodenal infusion of saline or glucose for 60 min. In study B, intravenous infusions were identical, but an oral mixed-liquid meal preload and a 60-min intraduodenal infusion of saline or oleic acid were administered. Thirty minutes after oral preloads, subjects ate and drank ad libitum, and amounts ingested and the time to meal completion were quantified. In addition, appetite and plasma GLP-1, peptide YY (PYY), insulin, glucagon, and blood glucose concentrations were measured.. In both studies, GLP-1, PYY, and glucagon were substantially higher with intravenous ex9-39 than with intravenous saline (P ≤ 0.001). Insulin was lower with intravenous ex9-39 during intraduodenal glucose (P ≤ 0.05). The decrease in prospective food consumption and desire to eat during ad libitum eating after glucose ingestion was slightly attenuated (P ≤ 0.05 and P ≤ 0.01, respectively) with ex9-39. However, with intravenous ex9-39, food and fluid intakes and eating duration were not changed in either study.. GLP-1 receptor antagonism slightly modulates appetite during ad libitum eating, but food and fluid intakes and meal duration remain unchanged, suggesting that endogenous GLP-1 is a weak satiation signal. However, concomitant substantial increases in plasma PYY and glucagon may counteract a desatiating effect of ex9-39. The effect of ex9-39 on PYY secretion supports an autoinhibitory feedback mechanism that controls L cell secretion; the effect on insulin and glucagon confirms the role of GLP-1 in glycemic control through its action on pancreatic α and β cells.

Topics: Adolescent; Adult; Appetite; Appetite Depressants; Cross-Over Studies; Double-Blind Method; Drinking Behavior; Energy Intake; Feeding Behavior; Glucagon; Glucagon-Like Peptide 1; Glucagon-Like Peptide-1 Receptor; Humans; Infusions, Intravenous; Male; Peptide Fragments; Peptide YY; Postprandial Period; Receptors, Glucagon; Up-Regulation; Vomiting; Young Adult

Non-ulcer dyspepsia (NUD) is a heterogeneous disorder, which is characterized by upper gastrointestinal symptoms and sensorimotor disturbances, including abnormal gastric emptying (GE) and increased intestinal chemosensitivity, and associated with greater plasma glucagon-like peptide-1 (GLP-1) levels during duodenal lipid infusion. However, the relationship(s) between these disturbances and daily symptoms in NUD is variable. We hypothesize that abnormal GE and symptoms during a GE study and during duodenal lipid infusion are associated with the severity of daily symptoms and that GLP-1 mediates symptoms during duodenal lipid infusion in NUD.. Gastric emptying of solids, symptoms during the GE study and duodenal lipid infusion, and daily gastrointestinal symptoms (2 week diary) were measured in 24 healthy controls and 40 NUD patients. During duodenal lipid infusion, participants received the GLP-1 antagonist exendin 9-39 or placebo.. In controls and patients, GE of solids was normal in 75% and 75%, delayed in 8% and 12.5%, or rapid in 17% and 12.5%, respectively. No controls but 26 patients (65%) had severe symptoms during the GE study. During lipid infusion, gastrointestinal symptoms were greater (P = .001) in patients and not affected by exendin. Symptoms during GE study and lipid infusion accounted for respectively 62% and 37% of variance in daily symptom severity.. In NUD, symptoms during a GE study and to a lesser extent during lipid infusion explain the variance in daily symptoms. Intestinal chemosensitivity is not reduced by GLP-1 antagonist. Assessment of symptoms during a GE study may provide a useful biomarker for NUD in research and clinical practice.

Topics: Abdominal Pain; Adult; Anxiety; Case-Control Studies; Depression; Diagnostic Techniques, Digestive System; Double-Blind Method; Duodenum; Dyspepsia; Female; Gastric Emptying; Gastrointestinal Transit; Heartburn; Humans; Intubation, Gastrointestinal; Lipids; Male; Nausea; Peptide Fragments; Radionuclide Imaging; Random Allocation; Satiety Response; Severity of Illness Index; Vomiting

The use of glucagon-like peptide-1 (7-36) amide (GLP-1) receptor agonists for the treatment of type 2 diabetes mellitus is commonly associated with nausea and vomiting. Previous studies using Suncus murinus revealed that the GLP-1 receptor agonist, exendin-4, induces emesis via the brainstem and/or hypothalamus. The present study investigated the mechanism of exendin-4-induced emesis in more detail. Ondansetron (1 mg/kg, s.c.) and CP-99,994 (10 mg/kg, s.c) failed to reduce emesis induced by exendin-4 (3 nmol, i.c.v.), suggesting that 5-HT3 and NK1 receptors are not involved in the mechanism. In other studies, the GLP-1 receptor antagonist, exendin (9-39), antagonised emesis and c-Fos expression in the brainstem and the paraventricular hypothalamus induced by the chemotherapeutic drug cisplatin (30 mg/kg, i.p.; p < 0.05), but not the emesis induced by nicotine (5 mg/kg, s.c.; p > 0.05), or copper sulphate pentahydrate (120 mg/kg, p.o.; p > 0.05). GLP-1 receptors may therefore represent a potential target for drugs to prevent chemotherapy-induced emesis in situations where 5-HT3 and NK1 receptor antagonists fail.

Topics: Animals; Antiemetics; Brain; Exenatide; Glucagon-Like Peptide-1 Receptor; Male; Ondansetron; Peptide Fragments; Peptides; Piperidines; Proto-Oncogene Proteins c-fos; Receptors, Glucagon; Shrews; Venoms; Vomiting