Serum concentrations of unconjugated and conjugated cholic acid in portal venous and systemic venous blood of fasting man.

The fasting concentrations of unconjugated and conjugated cholic acid were determined in the peripheral venous serum of 15 healthy subjects, eight patients with ileal resection and six patients with known bacterial overgrowth of the upper small intestine. In addition, the estimated hepatic uptake of unconjugated and conjugated cholic acid was determined in 15 gallstone patients undergoing cholecystectomy. A highly accurate and specific mass-fragmentographic technique with high sensitivity was used. The proportion of unconjugated cholic acid averaged 34% in the healthy subjects. The estimated fractional hepatic uptake of unconjugated cholic acid was lower than that of conjugated cholic acid, 71% and 87%, respectively (means). Patients with ileal resection had an increased proportion of unconjugated cholic acid in their peripheral venous serum, 49% (mean). The patients with bacterial overgrowth of the upper small intestine also displayed a high proportion of unconjugated cholic acid, 63% (mean). It is suggested that determination of the proportion of unconjugated cholic acid in peripheral venous blood may possibly be used for detection of bacterial contamination of the upper small intestine.