Cholecystektomy in hamster and mouse: Trophic effects on the pancreas and colon?

Cholecystectomy has been suggested to be a predisposing factor for both pancreatic and colonic cancer. We therefore investigated whether cholecystectomy caused any trophic effects on the pancreas and colon in the hamster and mouse. Cholecystectomy was performed on 13 hamsters and 11 mice. Seven of the hamsters and 6 of the mice were killed after 6 weeks, and 6 hamsters and 7 mice were killed after 3 months. Age-matched animals served as controls. One hour before sacrifice, the animals were given an intraperitoneal injection of tritiated thymidine (1 mCi/kg). Pancreatic wet weight, protein, water, amylase, and DNA content were analyzed. The labeling index of pancreatic acinar cells and colonic mucosal cells was determined and the mucosal thickness of the colon was measured. The concentration of plasma cholecystokinin was measured; it was not influenced by cholecystectomy in either the hamster or the mouse. No trophic effects were found in the pancreas 6 weeks or 3 months after cholecystectomy in the hamster, and the labeling index of pancreatic acinar cells was unchanged. In mice the pancreas weight was increased 6 weeks after cholecystectomy, but there was no corresponding increase in labeling index of the pancreatic acinar cells. After 3 months, there were no differences in the pancreatic weights, but the DNA content was decreased in cholecystectomized mice. Although there was a slight increase in the mucosal thickness of the hamster colon after 6 weeks, the labeling index of colonie mucosal cells and the mucosal thickness were unaffected by cholecystectomy in both hamsters and mice. The findings of the experiments do not support the idea that cholecystectomy exerts long-term trophic effects on the pancreas or colon.