ENHANCEMENT OF PANCREATIC-SECRETION BY DIETARY-PROTEIN IN RATS WITH CHRONIC DIVERSION OF BILE PANCREATIC-JUICE FROM THE PROXIMAL SMALL-INTESTINE

The regulation of exocrine pancreatic enzyme secretion by dietary prot ein is known to depend on pancreatic protease activity in the lumen of the proximal small intestine in rats, which is a negative feedback me chanism. We observed whether dietary protein stimulates pancreatic sec retion in rats with a 7-day diversion of bile pancreatic juice (BPJ) f rom the proximal small intestine under unrestrained and unanesthetized conditions. In the chronically BPJ-diverted rats, hypersecretion of p roteases in the fasting state were observed, and pancreatic enzyme sec retion was significantly increased after feeding of a 25% casein diet over the hypersecretion in the fasting state. The amplitude of the inc rements of the secretion after feeding in diverted rats was comparable to that in normal rats. Dietary fat decreased stimulated secretion by the protein diet in the diverted rats, but not in the normal rats. We conclude that there is an upper small intestinal BPJ-independent mech anism for response of pancreatic enzyme secretion to dietary protein, and that dietary fat inhibits pancreatic secretion in diverted rats. T he distal small intestine or colon may contribute to the inhibition.