Acute ethanol administration increases biliary concentrations of total and unconjugated bilirubin in rabbits

Epidemiological investigations have revealed that alcoholic cirrhosis is associated with a high frequency of pigment gallstones, but only scanty information is available on the effects of ethanol on biliary secretion of bilirubin. We have injected intravenously 1.0 and 1.5 g/kg body wt of ethanol into six cholecystectomized rabbits and a common bile duct fistula. Experiments were performed ten days after surgery and a stream-splitting apparatus was interposed in the circuit in order to withdraw continuously biliary samples without interruption of enterohepatic bile circulation. Analysis of hourly data showed that both ethanol doses significantly increase the biliary concentration of total bilirubin, without affecting bile flow and lipid composition. Alcohol also promoted the efflux of unconjugated bilirubin into bile. The maximum effect occurred within the first 5 hr following alcohol administration. Thereafter the bile returned to normal. Since excessive concentrations of biliary unconjugated bilirubin favor pigment gallstone development, it can be speculated that alcohol acts as a risk factor for pigment lithiasis by enhancing the biliary levels of this form of pigment.