HORMONAL-CONTROL OF EXOCRINE PANCREATIC-SECRETION IN THE ISOLATED INTACT RAT PANCREAS

This study employs the isolated perfused rat pancreas to investigate t he actions of the two gut hormones, cholecystokinin-octapeptide (CCK-8 ) and secretin on pancreatic juice flow and total protein output. Perf usion of the pancreas with either CCK-8 (100 pM) or secretin (100 pM) resulted in marked both pancreatic juice flow and total protein output . The effect of CCK-8 was three-fold larger compared to the responses obtained with secretin alone. Simultaneous application of CCK-8 and se cretin (all 100 pM) failed to elicit either a potentiation or an addit ive effect in both pancreatic juice flow and total protein output. The net increases in both secretory parameters were reduced during combin ed application of CCK-8 and secretin compared to the responses obtaine d with CCK-8 alone. The results indicate that optimal concentrations o f either CCK-8 or secretin can display marked secretagogue effects on the exocrine pancreas but when administered simultaneously they failed to elicit either an additive response or a potentiation-in pancreatic juice secretion.