GLUCAGON-LIKE PEPTIDE-1 INCREASES THE PERIOD OF POSTPRANDIAL SATIETY AND SLOWS GASTRIC-EMPTYING IN OBESE MEN

The gut peptide glucagon-like peptide 1(7-36) amide (GLP-1) is release d into the circulation after food intake. GLP-1 has been shown to have an incretin effect and inhibits gastrointestinal motility in humans. In rats, intracerebral administration of GLP-1 results in reduced food intake. Obese humans have been found to have an attenuated plasma GLP -1 response to a mixed meal. To approximate the physiologic state, GLP -1 or saline was administered intravenously and randomly at the beginn ing of a test meal served on a universal eating monitor to 6 obese sub jects to test our hypothesis that GLP-1 influences termination of food intake (and thus food intake during a meal) and feelings of satiety i n humans. As a marker for gastric emptying, 1.5 g acetaminophen was gi ven at the start of the meal. Blood samples for analysis of acetaminop hen, insulin, glucose, glucagon, and C-peptide were obtained. Hunger, fullness, and food choice were assessed with visual analogue scales an d food-choice questionnaires. GLP-1 infusion resulted in a prolonged p eriod of reduced feelings of hunger, desire to eat, and prospective co nsumption after the meal. The rate of gastric emptying was slower duri ng infusion of GLP-1. Postprandial blood glucose concentrations were r educed during the GLP-1 infusion, but the amount of energy consumed, e ating rate, and plasma concentrations of insulin, glucagon, and C-pept ide were unchanged. GLP-1 given exogenously at the start of a meal did not seem to affect meal termination or the amount of food eaten. Howe ver, postprandial feelings of hunger decreased, suggesting that exogen ous GLP-1 may influence feelings of hunger and satiety in humans.