Influence of bile and pancreatic secretions on the size of the intestinal villi in the rat

Abstract

Along the rat small intestine, the size of the villi gradually decreases from a maximum in the duodenum to less than half of this size in the terminal ileum. In previous work, various villus enlarging and reducing factors present in the intestinal chyme were found to control villus size. A villus enlarging factor which appeared to reach the intestine through the duodenal papilla was presently investigated.Transplants of duodenal papilla, together with a small segment of the duodenum, were made to isolated ileal segments and to the lower ileum. At both sites, the transplants elicited a marked villus enlargement within a month. A previous finding was that villus size decreased in isolated duodenal segments unless the duodenal papilla was present.In the next experiments, the bile-drainage was diverted from the duodenal papilla by implanting the bile duct into an isolated ileal segment which in turn was joined to the colon. The duodenal papilla which now transmitted only pancreatic secretions was then transplanted to the ileum. The bile caused only moderate villus enlargement in the ileal segments whereas marked villus enlargement took place in the ileum receiving the pancreatic secretions.It was concluded that a villus enlarging influence reached the intestine through the duodenal papilla. The pancreatic secretions appeared to play a major role in this influence.In the rat, the size of the intestinal villi decreases gradually from the duodenum toward the ileum so that the villi in the lower ileum are less than half the size of the duodenal villi (Altmann and Enesco, '67; Clarke, '70). In previous work, these regional differences in villus size were attributed largely to effects originating from the secretions and other materials making up the intestinal chyme (Altmann and Leblond, '70). Thus, secretions of the stomach and the duodenum were shown to contain villus enlarging factors whereas the ileal chyme appeared to contain villus reducing factors. Furthermore, there was evidence that the secretions reaching the intestine through the duodenal papilla also contained villus enlarging factors. The purpose of the present work was to confirm this latter observation and to find out whether the bile or the pancreatic secretions were involved. The method of approach was to transplant the duodenal AM. J. ANAT., 132: 167-178.papilla and the associated ducts into the ileum and also into isolated segments of the ileum. The influence of these transplants on villus size was then quantified.Male Wistar rats weighing 300-320 gm were used. The various procedures will now be described while the outline of the various experiments will be given in the Observations.Six control animals were maintained under normal laboratory conditions. They were provided with Purina Laboratory Chow and tap water ad libitum. Four additional animals received a semisynthetic diet instead of the Purina pellets. This diet contained 10% casein, 20% lactalbumin hydrolysate, 42% dextrose, 10% sucrose, 9% a mixture of vitamins, salt and yeast, 2% corn oi...

Effect of Chronic Pancreatic Juice Diversion on Enteroglucagon Secretion and Intestinal Mucosal Growth in Dogs.

“…In their model, a duodenal segment including the pancreatic duct was anastomosed to the ileum. They found thickening of ileal mucosa at the site receiving diverted pancreatic juice, while no changes were detected in the small intestinal mucosa proximal to the anastomotic site (Altmann 1972). In this model, however, bile was also diverted to the colon from the duodenum.…”

“…Altmann investigated the effects of luminal pancreatic juice and bile on the growth of small intestinal mucosa in rats; it was reported that pancreatic juice and bile had trophic effect on the intestinal mucosa (Altmann and Leblond 1970;Altmann 1972). In their model, a duodenal segment including the pancreatic duct was anastomosed to the ileum.…”

“…However, most of these models have involved the simultaneous diversion of both pancreatic juice and bile, and no studies have been reported examining mor-phological changes in the intestinal mucosa after diversion of pancreatic juice alone without changing biliary flow. This may be partly because it is technically difficult to keep the experimental animal in good condition after chronic diversion of pancreatic juice for a long duration (Altmann 1972).…”

“…pancreatic juice diversion; enteroglucagon; intestinal mucosal growth; pancreaticoileostomy It was previously reported that intestinal pancreatic juice plays an important role in intestinal adaptation (bowling 1982), and that pancreatic juice has a trophic effect on the small intestinal mucosa (Altmann and Leblond 1970;Altmann 1972). However, others have suggested that it is still controversial whether pancreatic juice has a trophic effect on intestinal mucosa (Miazza et al 1982).…”

New growth factor therapies aimed at improving intestinal adaptation in short bowel syndrome

“…39 Pancreatobillary secretions Increased secretions associated with hyperplastic response of the intestinal mucosa. [40][41][42][43] Hormones, e.g. growth hormone Mucosal proliferation (only in rodent studies).…”