Bile acid excretion: the alternate pathway in the hamster.

The quantitative significance of renal excretion of bile acid ester sulfates as an alternate excretory pathway was evaluated in hamsters. After bile duct ligation, total serum bile acid fell from a mean level of 454 microgram/ml at 24 h to 64 microgram/ml by 96 h. During this period the bulk of the bile acid pool could be accounted for as esterified bile acids in urine. Renal pedicle ligation of animals with bile duct obstruction led to retention of the bile acid ester sulfates in serum. Thioacetamide hepatotoxicity diminished ester sulfation of bile acids causing diminished renal secretion with relatively greater retention of nonesterified bile acids in serum. We conclude that secretion of esterified bile acids by the kidney is an efficient alternate pathway for maintaining bile acid excretion in obstructive biliary tract disease. Coexistent hepatocellular disease diminishes ester sulfation and the effectiveness of the alternate pathway in maintaining bile acid excretion.