Abstract
Pancreatic exocrine secretion in conscious rats is mainly regulated by protease activities in the duodenum. A decrease in protease activities by oral administration of trypsin inhibitors (TI)s produces pancreatic hypertrophy via cholecystokinin (CCK) release. Since luminal CCK releasing factor (LCRF), was purified from rat intestine, we determined whether the levels of LCRF, CCK, and protein secretion were synchronized with each other. Changes in pancreatic secretion, plasma CCK levels, and LCRF contents produced by 2- and 4-h bile-pancreatic juice diversion (BPJD), were determined in rats with 7-day TI treatment and compared with controls. The levels of LCRF and CCK changed in parallel. Pancreatic protein secretion was higher in rats treated with TI than in controls throughout the experimental period. The plasma CCK and luminal LCRF content 4-h after BPJD was significantly lower in rats treated with TI than in controls. The hypertrophied pancreas may require a smaller dose of CCK to increase protein secretion.
