Bile Acids in Rat Portal Blood. Bile Acids and Steroids 77

Tritium-labelled cholic acid was given to four rats and radioactive bile acids in the portal blood were analyzed with reversed phase partition chromatography after two days. One tenth to two tenths per cent of the radioactivity mixed with the bile acid pool was present in one ml of portal blood. About 15 per cent of the radioactive portal bile acids were unconjugated, approximately 50 per cent of which was deoxycholic acid as judged by its chromatographic behaviour. These figures have been used for rough calculations of the extent of enterohepatic circulation and cecal absorption of cholic acid and its metabolites, and for the estimation of the daily conversion of cholic acid into deoxycholie acid by intestinal microorganisms.