Diminished bile acid pool size in patients with gallstones.

The total and component bile acid pools were determined in 8 patients with gallstones and 9 patients without known gallstones by isotope dilution following the administration of 14C-cholic acid. Cholic acid half-life and production rate were calculated from the specific activity decay curves. Patients with gallstones were found to have significantly smaller total, cholic, and chenodeoxycholic acid pools than patients without gallstones. The average total bile acid pool was 1.29 g in patients with gallstones and 2.38 g in control patients without gallstones. Cholic acid production was significantly lower in patients with gallstones (206 mg per day) than in the control patients (358 mg per day). There was no significant difference in the cholic acid half-life between the groups. A mechanism responsible for the reduction in the bile salt pool in patients with gallstones is probably related to the inability of the liver to produce adequate amounts of bile acids to compensate for bile salt excretion. The findings of the present study also offer the interesting possibility that a diminished bile salt pool may be an important factor contributing to the production of the abnormal bile found in patients with cholesterol gallstones.