Neurohormonal control of pancreatic exocrine secretion

The neurohormonal control of pancreatic exocrine secretion is a complex interaction of multiple pathways involving a large number of gut hormones, neurotransmitters, and neuropeptides. Recent studies have elucidated a role for cholecystokinin in the regulation of bicarbonate and fluid secretion from pancreatic duct cells and suggested that cholecystokinin stimulation of human pancreatic acinar cells is likely regulated by an indirect mechanism of stimulation of afferent neurons. Evidence supports the regulation of potassium channels in rat pancreatic acinar cells by the cyclic AMP-mediated agonist secretin. Mechanisms for the regulation of cholecystokinin and secretin release by releasing factors have also been elucidated. The area postrema has been implicated in the mediation of inhibition of pancreatic secretion by the gut hormones peptide YY and pancreatic polypeptide. The neurotransmitter serotonin has been demonstrated to play a role in acid-induced secretin release and in pancreatic secretion stimulated by luminal factors. The regulation of pancreatic exocrine secretion by purines, nitric oxide, and gamma-aminobutyric acid as well as by the neuropeptides pituitary adenylate cyclase-activating peptide, gastrin-releasing peptide, and substance P is reviewed. The role of the central nervous system in modulating pancreatic secretion is also described. This review highlights the recent advances in knowledge of the neurohormonal regulation of pancreatic exocrine secretion.