INHIBITION OF EXOCRINE PANCREATIC-SECRETION BY SOMATOSTATIN AND ITS ANALOGS

The stimulation of exocrine pancreatic secretion has extensively been studied in the past. On the other hand, little is known about the fact ors and mechanisms which regulate inhibition of exocrine pancreatic se cretion. This review, therefore, focuses on somatostatin as one candid ate of several peptides which may physiologically mediate inhibition o f pancreatic secretion and on its possible mode of action. Somatostati n probably inhibits pancreatic exocrine secretion by a variety of mech anisms which depend on the species and the type of secretion studied ( postprandial vs. interdigestive secretion, protein vs. bicarbonate sec retion): Somatostatin may act via inhibition of the release of circula ting hormones such as cholecystokinin (CCK) and secretin or via intrap ancreatic inhibition of the release or action of CCK. Somatostatin may inhibit acetylcholine release from nerve terminals which express spec ific somatostatin receptors or directly affect the secretory response of the acinar cells via specific somatostatin receptors by a reduction of intracellular cAMP. Somatostatin may also indirectly alter the pan creatic response to a meal by its extrapancreatic effects, e.g. inhibi tion of gastric secretion, gastric emptying, bladder emptying and gast rointestinal motility.