EFFECT OF BILIARY OBSTRUCTION AND PINEALECTOMY ON RAT GASTROINTESTINAL CRYPT CELL-KINETICS

Following pinealectomy, there is hyperproliferation of liver cells as well as small bowel crypt cells. Since an increased level of intralumi nal bile is also associated with increased crypt cell proliferation, t he possible role of an increase in bile production in the hyperprolife rative effects of pinealectomy was investigated by combining pinealect omy with complete biliary obstruction. This procedure was not associat ed with any diminution in the hyperproliferative effects of pinealecto my in rats. It appears, therefore, that the hyperproliferative effect of pinealectomy on the crypts does not depend on changes in the level of intraluminal bile.