“…At least five different endocrine cell types have been recognized in the pancreas which elaborate polypeptides and amines (serotonin), and an occasional overproduction of some hormones by tumors, causing syndromes, would not be unexpected. These actions include inhibition of the release of insulin and glucagon from the pancreas and suppression of the secretion and/or action of gastrin, secretin, cholecystokinin (CCK), and VIP (4,154,155). Entopic endocrine tumors include insulinomas, glucagonomas, somatostatinomas, and pancreatic polypeptide (PP) islet cell tumors (PPomas, PP apudomas) ( 154).…”