Pituitary adenylate cyclase activating polypeptide (PACAP) is a highly conserved neuropeptide that is widely expressed in the mammalian brain. PACAP acts by elevating intracellular cyclic AMP level via its interaction with its receptors.

PACAP is an important regulator of endocrine and homeostatic processes, such as secretion of pituitary and gut hormones and food intake.