Conjugated and Unconjugated Serum Bile Acid Levels in Patients with Hepatobiliary Diseases

Abstract

Total and unconjugated bile acid levels in serum of patients with various hepatobiliary diseases were determined by gas-liquid chromatography. In normal serum, ranges of total serum bile acid were found as follows: deoxycholic acid 0.22 ± 0.14, chenodeoxycholic acid 0.23 ± 0.14, cholic acid 0.14 ± 0.09, and total amount of bile acid 0.59 ± 0.31 μg per ml. The cholic to chenodeoxycholic acid ratio (C:CDC) was 0.61 ± 0.30. In hepatobiliary diseases, the level of total serum bile acid rose. The increase was remarkable in acute early hepatitis and in obstructive jaundice but moderate or slight in active portal cirrhosis and chronic hepatitis. Changes in the composition of serum bile acid were also observed. The C:CDC ratio was 1.01 ± 0.43 in portal cirrhosis and 2.74 ± 1.42 in obstructive jaundice. A correlation was observed between the total serum bile acid level and the serum bilirubin concentration in obstructive jaundice and portal cirrhosis. Unconjugated serum bile acid levels in healthy persons showed a range of 0.26 ± 0.20 μg per ml; and the unconjugated to total bile acid ratio (U:T) was 51.4 ± 22.0 %;. In active portal cirrhosis, the amount of unconjugated bile acid increased (2.54 ± 1.83 μg per ml). The value was significantly higher than that in normal, chronic hepatitis, and obstructive jaundice groups. Contrary to portal cirrhosis, the whole increase in serum bile acid in obstructive jaundice was occupied by conjugated bile acid and the U:T ratio was very low (0.2 ± 0.4%). A possible cause for the rising of the total and unconjugated serum bile acid levels in hepatobiliary diseases is discussed.