GLP-1(7-37) (A) but not GLP-1(1-37) (B) stimulates insulin secretion from the perfused rat pancreas as adapted from ref. 24. Sequences of GLP-1(1-37), GLP-1(7-37), and GLP-1(7-36amide). (C) Intraluminal glucose stimulates enteroglucagon, GLP-1, and GLP-2 secretion from the perfused pig ileum (D), as adapted from ref. 17. Demonstration that GLP-1(7-36)amide stimulates insulin secretion from the perfused pig pancreas (E), as adapted from ref. 25.