Effect of carbon tetrachloride on biliary excretion of 3,4-benzpyrene in rats]

14C-labelled 3,4-benzpyrene (14C-BP) in dose of 100 mug/animal was injected into female Sprague-Dawley rats under urethane anesthesia. The rats were cannulated at the duct and the output of metabolites in the bile was determined. Non-treated rats excreted 35.5% of the given dose within one hr. The main metabolites excreted in bile were fractionated chromatographically into three. One of these was a metabolite which was hydrolyzed by beta-glucuronidase, the other two were unknown substances. Unchanged BP was not detected. In rats pretreated with CCl4 (0.5 ml/kg, p.o.) 24 hr before experiment, the biliary excretion of BP-metabolites was found to be reduced, that is only 10% of the given dose was excreted within one hr. It was noted that the output within the first 90 min after injection of BP was significantly reduced. In the CCl4-treated rats, bile flow was found to be lowered. However, the reduced output of BP-metabolites was considered not as the result of lowered bile flow, but as the result of disturbance of BP-metabolism in the liver. Thus it is suggested that impaired hepatic junction as the result of CCl4 intoxication may last for more than two weeks, when the hepatic junction is evaluated in terms of biliary excretion of BP.