Secretion of pancreatic polypeptide in human pancreas

A photomicrograph of a stained section through a normal human pancreas, showing PP cells secreting pancreatic polypeptide (red) in the islets of Langerhans. Pancreatic polypeptide affects the secretion of pancreatic enzymes, water and electrolyes, and influences gut motility and the relaxation of the sphincters of the gut and gall bladder. Its secretion is elevated in patients with duodenal ulcers and type I diabetes, and depressed in pancreatitis. Its secetion is also affected by various types of pancreatic and gastrointestinal tumours.