hormone activity pituitary adenylate cyclase activating polypeptide activity molecular_function The action characteristic of pituitary adenylate cyclase activating polypeptide, a peptide produced in the hypothalamus that binds to receptors to exert pleiotropic effects including control of neurotransmitter release, vasodilation, bronchodilation, activation of intestinal motility, increase in insulin and histamine secretion, immune modulation, and stimulation of cell proliferation and differentiation. pituitary adenylyl cyclase activating polypeptide activity GO:0016521