title: Exendin-4, a GLP-1 receptor agonist, interacts with proteins and their products of digestion to suppress food intake in rats.
abstract: This study investigated the hypotheses that dietary proteins suppress food intake partly through the glucagon-like peptide-1 (GLP-1) signaling pathway, and that this effect is mediated by products of protein digestion. The GLP-1 receptor agonist, Exendin-4 (Ex-4) (0.5 micro g/rat), was given intraperitoneally to male Wistar rats, and food intake was measured when Ex-4 was given alone or with preloads of intact whey and casein proteins, their hydrolysates and amino acid mixtures (0.5 g x 4 mL(-1) x rat(-1)). Both Ex-4 and the preloads suppressed food intake (P < 0.05), but the effect of Ex-4 on food intake was reduced when coadministered with the preloads (P < 0.05). Because the effect of Ex-4 was reduced by the protein hydrolysates and by the amino acid preloads, the results support a role for the end products of protein digestion and GLP-1 release in the suppression of food intake in response to protein ingestion. We concluded that the GLP-1 signaling pathway, activated by the release of products of protein digestion, is another mechanism accounting for the reduction of food intake after protein ingestion.
authors.affiliation: Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada M5S 3E2.
authors.forename: Alfred
authors.initials: A
authors.lastname: Aziz
authors.forename: G Harvey
authors.initials: GH
authors.lastname: Anderson
mesh_terms: D000596:Amino Acids / Q000008:administration & dosage; D000818:Animals; D004063:Digestion; D002149:Energy Intake / Q000187:drug effects*; D000077270:Exenatide; D000067757:Glucagon-Like Peptide-1 Receptor; D008297:Male; D010455:Peptides / Q000378:metabolism / Q000494:pharmacology*; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D018027:Receptors, Glucagon / Q000819:agonists*; D014688:Venoms
chemical_list: D000596:Amino Acids; C000593835:Glp1r protein, rat; D000067757:Glucagon-Like Peptide-1 Receptor; D010455:Peptides; D011506:Proteins; D018027:Receptors, Glucagon; D014688:Venoms; D000077270:Exenatide