NEUROHUMORAL CONTROL OF THE EXOCRINE PANCREAS

This review includes discussions on recent advances in neurohumoral interactions that emphasize important neuronal roles in the actions of gut hormones, roles of neuropeptides and nitric oxide, feedback regulation of the exocrine pancreas, and physiologic significance of insulo-acinar axis. The actions of gut hormones on the exocrine pancreas in physiologic conditions are mediated mainly via either vagal sensory afferent or vagal efferent cholinergic pathways, or a central vagal site. Neuropeptides appear to exert their actions on the pancreas, not directly on acini; they are mediated via releases of hormones or via neuronal pathways. In feedback regulation of the exocrine pancreas, pancreatic proteases in gut lumen control the release of cholecystokinin and secretin, thereby controlling pancreatic secretion. Lastly, the local mediation of insulin in the exocrine pancreas is essential for the actions of cholecystokinin and secretin on the exocrine pancreas.