The Human Glucagon-Like Peptide-1 (GLP-1) Receptor

At similar plasma glucose concentrations much greater insulin secretion is achieved with oral glucose than with intravenous glucose. These observations lead to the concept that gastrointestinal factors (incretins) are released by nutrients, particularly glucose, to potentiate insulin release (Creutzfeldt, 1979). The two most potent incretins, GLP-1(7–37) and its amidated form GLP-1(7–36 amide), are processed from the parent 37 amino acid GLP-1 peptide, which is produced in intestinal L-cells as a posttranslational product of preproglucagon.