METABOLISM OF 3ALPHA, 7ALPHA, 12ALPHA-TRIHYDROXY-5BETA-CHOLESTAN-26-OIC ACID IN NORMAL SUBJECTS WITH AN INTACT ENTEROHEPATIC CIRCULATION

Abstract

The formation of cholic acid from 3.alpha.,7.alpha.,12.alpha.-trihydroxy-5.beta.-cholestan-26-oic acid (THCA) was studied in 2 normal subjects. [3H]THCA and [14C]cholic acid were administered i.v. by simultaneous injection and the specific activities (percent injected amount/.mu.mol) of [3H]- and [14C]cholic acid were measured in bile samples collected over a 5 day period. If the administered [3H]-THCA was rapidly and completely metabolized into cholic acid, the areas under the specific activity curves of [3H]- and [14C]cholic acid would be identical. In these 2 subjects, the area under the [3H]cholic acid specific activity decay curves was only 18.4 and 9.0% < the area under the [14C]cholic acid specific activity decay curves. There was rapid and nearly complete metabolism of i.v. administered [3H]THCA into cholic acid.