Studies on the Formation of Cholic Acid in Subjects Given Standardized Diet with Butter or Corn Oil as Dietary Fat

Abstract

The half-life, pool size and turnover of cholic acid was determined in nine normal and four hypercholesteremic subjects after the administration of cholic acid-24-C¹⁴. The subjects were given a standardized frozen diet prepared with either butter or corn oil as the dietary fat. There was a considerable difference in the turnover of cholic acid between the different subjects but less variation when the same subject was studied twice on the same diet. The turnover cholic acid was higher in six of the normal subjects when they were given the corn oil-contaning version of the diet than when they were given the butter-containing version, but the differences were not statistically significant. In the hypercholesteremic subjects there was no significant effect of the diet on the turnover of cholic acid. It is concluded that the decrease in the concentration of serum cholesterol caused by the inclusion of mainly unsaturated fat in the diet was not caused by an increased formation of bile acids from cholesterol. In the normal subjects the half-life of cholic acid was 3.2 days on both types of diet, the pool size on the butter- and corn oil-containing versions was 1.12 and 1.30 gm., respectively, and the turnover was 0.296 and 0.314 gm per day, respectively. A paper chroinatographic technic was used to determine the ratio of glycine to taurine conjugated bile acids and the relative concentrations of cholic chenodeoxycholic and deoxycholic acids in duodenal bile. About 70 per cent of the bile acids were conjugated with glycine, irrespective of the type of diet. Cholic acid accounted for 34 to 39 per cent of the total bile acids, there being a tendency for lower values when the subjects were given the butter-containing version of the diet. Deoxycholic acid accounted for 25 to 29 per cent of the total bile acids in the normal subjects and for 14 to 16 per cent in the hypercholesteremic subjects.