Pancreatic Polypeptide is an agonist at Y4 neuropeptide Y receptros. Pancreatic polypeptide (PP) is a 36-amino-acid secretory peptide that is predominantly produced by the pancreas. The exact physiologic role of PP in healthy individuals has not been fully defined. It has been shown, however, that pancreatic polypeptide affects the secretion of pancreatic enzymes, water, and electrolytes. Its effect is biphasic in that PP initially enhances secretion and then inhibits secretion. PP increases gastric emptying and gut motility. Pancreatic polypeptide also relaxes the pyloric and ileocecocolic sphincters, the colon, and gallbladder. PP levels increase after ingestion of food and remain elevated from four to eight hours.