An incretin hormone; binds to βTC-1 and RIN 1027-B2 cells (Kds = 3.3 and 3.5 nM, respectively); enhances insulin secretion in βTC-1 cells in a concentration- and glucose-dependent manner; stimulates insulin release from perfused rat pancreas; increases plasma insulin concentrations by greater than 50% as compared to vehicle control in response to hyperglycemia in rats (15 pmol/min/kg for 5 days) ,