pancreatic polypeptide

Pancreatic polypeptide is the islet's least famous hormone, made by the so-called PP cells (or F cells), and its main concerns are digestion and appetite rather than blood sugar directly. Think of it as a post-meal housekeeper: after you eat, it helps tone down some digestive secretions and contributes to the signal that you have had enough.

PP is released after meals in proportion to how much you ate, driven largely by the vagus nerve. It tends to reduce pancreatic exocrine (enzyme) secretion and gallbladder contraction, and it acts on the brain to promote satiety, fitting into the broader family of appetite-regulating gut hormones such as PYY and GLP-1.

Although a minor player physiologically, PP has clinical uses as a marker. Its blood level can be markedly elevated by certain pancreatic neuroendocrine tumors, so it is sometimes measured when such tumors are suspected. Conversely, a blunted PP response can reflect vagal nerve damage, for instance in autonomic neuropathy.