Pancreatic polypeptide

Where it comes from

Made in

PP cells (F cells) of the islets, most of them in the head of the pancreas

Sent out by

Protein meals, through the vagus nerve; fasting lowers it

Acts on

• Brainstem and hypothalamus
• Exocrine pancreas
• Gallbladder

What it does

• Reduces food intake, and the effect lasts hours ¹
• Holds back pancreatic enzyme secretion and gallbladder contraction
• Its rise after a meal is a test of the vagus nerve

In medicine

• Measured as a marker of pancreatic neuroendocrine tumours and of vagal nerve damage
• Low in Prader-Willi syndrome and after removal of the pancreatic head

Beyond the body’s own use

• An infusion of pancreatic polypeptide cut what lean volunteers ate over the following 24 hours by about a quarter, which is what made the Y4 receptor an obesity target ¹
• Y4 agonists were taken into obesity trials, obinepitide among them, and dropped after phase 2; no Y4 medicine has been approved for anything ²
• The pharmacology is being worked out again from the receptor’s structure, in the hope of separating appetite from the gut side effects ²