Exendin-3 is a biologically active peptide isolated from the venom of Heloderma horridurn (Gila monster lizards). As a pancreatic secretagogue, it belongs to the glucagon family.
Exendin (5-39) is a powerful antagonist of the glucagon-like peptide 1 (GLP-1) receptor with the ability to ameliorate memory impairment in rats treated with β-amyloid protein.