Stimulates vasoactive intestinal peptide (VIP) receptors in high concentrations (>100 nM), resulting in both an increase in cAMP and amylase secretion from pancreatic acini, although at low concentrations (between 0.3 and 3 nM) it increases cAMP without stimulating amylase release. Stimulates the GLP-1 receptor (GLP1R). Induces hypotension that is mediated by relaxation of cardiac smooth muscle. Expressed by the venom gland. [Lys(40)((68)Ga-DOTA)]exendin-3 is a promising tracer to visualize insulinomas (neuroendocrine tumors derived from pancreatic beta-cells in which GLP1R is expressed at >90%) with PET imaging. Belongs to the glucagon family.