Responses of the Exocrine Pancreatic Secretion to Spontaneous Feeding in Rats with Bile-Pancreatic Juice Diversion

Abstract

The regulatory response of the exocrine pancreas was examined in rats under unanesthetized and unrestrained conditions. The previous study demonstrated that the pancreatic protease secretion increased 2-fold after spontaneous feeding of a low protein diet in chronically bile-pancreatic cannulated rats (normal rats) whose bile-pancreatic juice (BPJ) was returned to the duodenum. In the present study, we observed the response of the exocrine pancreatic secretion to spontaneous feeding of a low protein diet in rats with chronic diversion of BPJ from the proximal small intestine for 6 days (bypass rat) whose diverted BPJ was returned to the upper ileum. During BPJ diversion, the dry weight and the protein content of the pancreas were increased 2-fold, compared with normal rats. Also, the levels of trypsinogen and chymotrypsinogen in the pancreas were increased several times, but amylase was decreased. The basal secretion of enzymes after a 24-hr fast was enhanced in bypass rats in proportion to the pancreatic enzyme contents. After spontaneous feeding of 8% casein fat-free diet, the increases in the pancreatic secretion of bypass rats were much smaller than those of normal rats. In contrast, the increase of BPJ flow of bypass rats after feeding was greater than that of normal rats. These findings represent that the chronic diversion of BPJ exerts hypergrowth of pancreas and hypersecretion of proteases in the fasting state, and less sensitivity of pancreatic enzyme secretion to dietary feeding.

Changes in Messenger RNA of Pancreatic Enzymes and Intestinal Cholecystokinin after a 7-Day Bile-pancreatic Juice Diversion from the Proximal Small Intestine in Rats

“…The sensitivity of pancreatic acini to cholecystokinin, but not to carbachol, has been found to be lowered by chronic BPJ diversion,2) and pancreatic proteases to be markedly induced by chronic diversion. 3,4) The pancreatic changes tended to be similar to those with adaptation to a high protein diet,5.6) but adaptation to a chronic BPJ diversion has not been completely characterized.…”

Intestinal Fat Suppresses Protein‐Induced Exocrine Pancreatic Secretion in Chronically Bile‐Pancreatic Juice‐Diverted Rats

“…Long‐chain fatty acids are known to increase exocrine pancreatic secretion (1–3). We have developed a test system to examine BPJ‐independent control of the exocrine pancreas using rats whose bile‐pancreatic juice (BPJ) was chronically diverted from the proximal small intestine (4). In the BPJ‐diverted rats, dietary protein increases enzyme output from the pancreas independent of BPJ (5, 6).…”