The role of glucagon-like peptide 1 in the regulation of glucose homeostasis and satiety

Glucagon-like peptide 1 (GLP-1) is an insulinotropic peptide secreted by intestinal L-cells (mucosal cells belonging to the APUD (amine precursor uptake and decarboxylation) system in response to oral food intake. GLP-1 is co-encoded in the proglucagon gene and while post-translational processing of proglucagon in the pancreas gives rise to glucagon, GLP-1 (7–36 amide) is produced in the intestine and to a lesser extent in the hypothalamus. The postprandial secretion of an intestinal factor that lowers plasma glucose levels (incretin) had already been hypothesized a century ago. However, only 10 years ago, when GLP-1 was discovered as a second incretin besides gastric inhibitory peptide (GIP), this concept of an entero–insular axis became established. Since the