The biotransformed metabolite profiles in blood after intravenous administration of dehydrocholic acid.

One gram of dehydrocholic acid was injected intravenously into two patients with percutaneous transhepatic cholangial drainage, and the biotransformed metabolites profiles over a 120-min period in serum and bile were analyzed. In serum unconjugated 3 alpha-hydroxy-7,12-dioxo-cholanoic acid (3 alpha-OH-7,12-OXO) acid was markedly increased after the injection of dehydrocholic acid, and reached about 80 microM within 30 min. On the other hand, conjugated 3 alpha, 7 alpha-dihydroxy-12-oxo-cholanoic acid (3 alpha,7 alpha-OH-12-OXO) was consecutively increased with lag time to an elevation of 3 alpha-OH-7,12-OXO. In bile, the major constituent of metabolites was conjugated 3 alpha,7 alpha-OH-12-OXO (more than 90% of the excreted metabolites), while conjugated 3 alpha-OH-7,12-OXO was detected as minor constituent. Therefore, between bile and serum, there was great difference in biotransformed metabolites profiles. The mechanism of elevation of unconjugated 3 alpha-OH-7,12-OXO in serum remains obscure, but this new finding raised a question as to whether organ-reducing 3-keto group of dehydrocholic acid is restricted to the liver.