The effects of temporary occlusion of the superior mesenteric vein or splenic vein on biliary bilirubin and bile acid excretion in rats.

Abstract

To elucidate the possible implication of hepatic blood supply to the occurrence of hepatolithiasis, the rat superior mesenteric vein, which drains blood from the intestine, or the splenic vein, which drains from the spleen, was occluded for 30 minutes. Changes in the hepatic oxygen saturation index, intrahepatic uridine diphosphate-glucuronic acid concentration, bile flow, and the excretion of bilirubin as well as its fraction, along with bile acid in bile before and after the procedure, were observed. In association with superior mesenteric vein occlusion, oxygen saturation index, hepatic uridine diphosphate-glucuronic acid concentration, bile flow, bile acid concentration in bile, and percentage of biliary bilirubin diglucuronide were all decreased. Incubation of bile under sterile conditions from rats with occluded superior mesenteric veins resulted in precipitation of mainly calcium salt of fatty acid. In contrast, splenic vein occlusion caused no changes except for a decrease in biliary bilirubin concentration. Incubation of bile from rats with occluded splenic veins did not induce precipitation. From these findings it can be concluded that blood flow in the superior mesenteric vein is the primary source of oxygen supply to the rat liver and that this vein plays an important role in maintaining bile flow, bile acid excretion, and bilirubin conjugation and in preventing the precipitation of bile (possibly preventing hepatolithiasis).