PathwayStep2058 PathwayStep2065 Incretin Synthesis, Secretion, and Inactivation Authored: May, B, 2009-05-18 21:31:59 Edited: May, B, 2009-05-18 21:31:59 GENE ONTOLOGYGO:0050796 Incretins are peptide hormones produced by the gut that enhance the ability of glucose to stimulate insulin secretion from beta cells in the pancreas. Two incretins have been identified: Glucagon-like Peptide-1 (GLP-1) and Glucose-dependent Insulinotropic Polypeptide (GIP, initially named Gastric Inhibitory Peptide). Both are released by cells of the small intestine, GLP-1 from L cells and GIP from K cells.<br>The control of incretin secretion is complex. Fatty acids, phospholipids, glucose, acetylcholine, leptin, and Gastrin-releasing Peptide all stimulate secretion of GLP-1. Fatty acids and phospholipids are the primary stimulants of secretion of GIP in humans (carbohydrates have more effect in rodents).<br>Incretins secreted into the bloodstream are subject to rapid inactivation by Dipeptidyl Peptidase IV (DPP IV), which confers half-lives of only a few minutes onto GLP-1 and GIP. Inhibitors of DPP IV, for example sitagliptin, are now being used in the treatment of Type 2 diabetes. Pubmed17263764 Pubmed17498508 Pubmed19074620 Reactome Database ID Release 43400508 Reactome, http://www.reactome.org ReactomeREACT_23974 Reviewed: Bloom, SR, 2010-06-24 Synthesis, Secretion, and Inactivation of Glucose-dependent Insulinotropic Polypeptide (GIP) Synthesis, Secretion, and Inactivation of Glucagon-like Peptide-1 (GLP-1)