Pancreatic polypeptide inhibits amylase release by rat pancreatic acini

Pancreatic polypeptide (PP), a mammalian islet cell peptide, is released after a meal. Exogenously administered PP in physiologic doses inhibits cholecystokinin and secretin-stimulated pancreatic secretion in vivo. Whether PP acts directly on exocrine pancreatic cells is unknown. We studied the effects of PP on dispersed acini prepared from rat pancreas. Amylase release was determined after 30-min incubations of pancreatic acini with octapeptide of cholecystokinin (OP-CCK), secretin, and PP. The response to OP-CCK was augmented by secretin. PP decreased optimal amylase release evoked by OP-CCK and OP-CCK plus secretin. These observations demonstrate that PP acts directly on pancreatic cells to reduce acinar cell amylase release evoked by potent secretagogues.