Conjugation and excretion of 14C-chenodeoxycholic acid during total extrahepatic cholestasis

14C-chenodeoxycholic acid was administered intravenously to two patients with total extrahepatic cholestasis subjected to external biliary drainage 38 and 132 h after administration. The disappearance from serum and the renal and hepatic excretion of labelled compounds were followed. Labelled conjugates were separated chromatographically and quantified. Two hours after administration almost all radioactivity in the serum was in the form of glycine or taurine conjugates and after 36 h about 20% of the labelled conjugates in serum were sulphates. The disappearance of radioactivity from the serum was slow, due to low renal elimination. Almost all the chenodeoxycholic acid excreted in the urine was sulphated. During the biliary drainage only a minor portion of the labelled chenodeoxycholic acid administered was excreted in the bile; hepatic elimination did not exceed the concomitant renal excretion.