LACK OF RESPONSE TO DIETARY-PROTEIN IN PANCREATIC-SECRETION BY CHRONIC DEPRIVATION OF JEJUNAL CHYME IN RATS

Background: Exocrine pancreatic secretion is regulated by luminal fact ors, bile-pancreatic juice (BPJ), and food chyme. The effects of 10 da ys' chronic deprivation of luminal chyme on the stimulation of exocrin e pancreatic secretion by dietary protein were examined in rats with o r without BPJ in the jejunum. Methods: The jejunum was deprived of ing ested food by preparing a whole-jejunum blind loop. The BPJ was divert ed by a common bile-pancreatic duct catheter and was returned to the u pper jejunum (with BPJ) or ileum (without BPJ). Results and Conclusion : In rats with the ingested food and BPJ in the jejunum (control), sec retion rates in terms of volume, protein, amylase, and trypsin increas ed more than twofold from the rates in the fasting state after a jejun al injection of peptic hydrolysate of casein. In contrast, the secreti ons were not increased by the protein injection in the rats deprived o f jejunal chyme with or without BPJ in the jejunum. Even in the chyme- deprived group the protein and trypsin secretion of the fasting state was significantly higher in BPJ-diverted rats than in rats with BPJ. T hese results showed that chronic deprivation of the jejunal chyme impa ired responses of the exocrine pancreas to dietary protein but not the hypersecretions of the pancreas by BPJ diversion.