GLP-1(7–36)amid (GLP-1) mediates the ‘ileal brake’ in human

Nutrients appearing in the distal intestine induce a delay of upper gastrointestinal transit and inhibit gastropancreatic secretion. This ‘ileal brake’ is the primary inhibitory feedback mechanism that controls transit and digestion of a meal. The factors mediating this response are unknown. GLP-1 is a gut hormone postprandially released from intestinal L-cells. Well known endocrine effects of GLP-1 are stimulation of insulin and inhibition of glucagon release. However, the importance of the predominant presence of L-cells within the lower gut is not known. As GLP-1 is released by ileal nutrients, it is suggested as a humoral mediator of the ileal brake. Therefore, we examined the effects of ileal nutrients on pancreatic enzyme and gastric acid secretion with and without the specific GLP-1 receptor antagonist exendin(9–39).