Proximal jejunal and biliary effects on the enteroinsular axis

The objective of this study was to investigate the roles of the proximal jejunum and endogenous bile within the proximal jejunum on the enteroinsular axis. Twelve Sprague-Dawley rats underwent proximal jejunal bypass, 11 rats underwent Roux-en-Y cholangiojejunostomies, and 12 rats underwent sham operations. After 3 months, oral glucose tolerance tests were performed in unanesthetized animals and venous blood was collected for plasma glucose and insulin measurements. The surgical procedures did not significantly affect the basal glucose and insulin levels compared with sham-operated animals. The insulin response in rats with excluded proximal jejunal segments was inhibited. The decreased insulinogenic index seen in these animals indicates a possible diabetogenic effect of this procedure. An oral glucose challenge resulted in significant hyperinsulinemia, with an increased insulinogenic index in animals that had undergone Roux-en-Y cholangiojejunostomies. These findings suggest that bile is a potential mediator in the proximal jejunal involvement in the enteroinsular axis.