Morphological changes of the adapting small intestine deprived of gastric, duodenal, biliary and pancreatic secretions in the rat.

In order to examine the importance of certain gastrointestinal secretions in the adapting small intestine, four groups of rats were operated upon. In group 1 (controls), laparotomy and suture-marking of the small intestine were carried out. In group 2, a jejuno-ileostomy was established, resulting in a bypass of about 85% of the small intestine. In group 3, in addition to a similar bypass the secretions from duodenum, pancreas an the bile were diverted to the transverse colon. In group 4, in addition to the operations in group 3, the gastric secretion was also diverted to the colon. 14 days after operation, the wet and dry weight per 3 cm intestine and the villus height were determined from a jejunal and an ileal segment in circuit and also from the top of the blind loop. Both shunt-operation alone and shunt-operation with diversion of duodenal, pancreatic and bile secretion resulted in hypertrophy of both jejunum and ileum in circuit. Shunt-operation with diversion of gastric, duodenal, pancreatic and bile secretion resulted in moderate hypertrophic changes of the jejunum and ileum in circuit compared with controls. The top of the blind loop was atrophied in groups 2-4. The experiments demonstrate that the presence of duodeno-pancreatico-biliary secretions is not indispensable for the development of compensatory hypertrophic changes in the small intestine. The importance of gastric secretions in this respect cannot be evaluated because of the serious malabsorption of the experimental animals.