Adaptive hepatic changes in mild stenosis of the common bile duct in the rat

Adaptive hepatic changes were investigated in rats with mild stenosis of th e common bile duct and in sham-operated controls. The studies were performe d 24 h and 7-12 days postoperatively. A continuous intravenous in fusion of taurocholic acid at stepwise-increasing rates was performed to explore the responses to bile acid effects. During the infusion, bile now and the outp uts of bile acids, phospholipids, cholesterol, alkaline phosphatase and gam ma glutamyl transpeptidase were studied. At the end of the infusion, hepati c morphometric measurements were performed. In other experimental sets, bil iary excretions of horseradish peroxidase, a marker of microtubule-dependen t vesicular transport in the hepatocyte, and sulphobromophthalein, a well-k nown organic anion model, were studied. In other rats, bile acid pool size and composition were determined by depletion of bile. The results in rats w ith mild stenosis maintained for 24 h showed a greater susceptibility to th e toxicity of taurocholic acid, as revealed by the abrupt decrement in bile now at high rates of infusion, and increased outputs of phospholipids and canalicular enzymes. Conversely, rats with mild stenosis maintained for 7-1 2 days showed de creased bile acid maximum secretory rate and biliary outpu ts of phospholipids and canalicular enzymes, as well as hepatocyte hypertro phy. These findings may explain the limited hepatic and systemic repercussi on of experimental mild stenosis of the common bile duct and help us to und erstand the early stages of constriction of the common bile duct in man.