Changes in the binding of radioactive conjugated bile salts to serum proteins in cholestatic jaundice.

1. A micro-partition centrifugal ultrafiltration technique has been used to monitor the percentage of [14C]glycocholate, [3H]glycochenodeoxycholate and [3H]glycochenodeoxycholate-3-sulphate bound to serum proteins of patients with cholestatic liver disease. 2. In comparison with normal individuals the percentage of binding of [14C]glycocholate and, to a lesser extent, of [3H]glycochenodeoxycholate and [3H]glycochenodeoxycholate-3-sulphate was reduced. 3. The binding of [14C]glycocholate was inversely related to the serum bile salt and bilirubin concentrations. In contrast, the binding of [3H]glycochenodeoxycholate and [3H]glycochenodeoxycholate-3-sulphate were not altered by the severity of the cholestasis. 4. Studies in vitro indicated that the reduction in the binding of [14C]glycocholate in cholestatic liver disease was not due to high concentrations of bile salts, unconjugated bilirubin or fatty acids.