Bile pigment formation and excretion in the rabbit

Abstract

1. 1. Bile and plasma levels of biliverdin and bilirubin, together with the hepatic biliverdin reductase and bilirubin UDP-glucuronosyl transferase activities, were studied in the rabbit. 2. 2. No biliverdin could be detected in the blood plasma. The bilirubin concentration in blood was 7.81 ± 0.79 μmol/1. 3. 3. Biliverdin was the predominant pigment in bile (63%). 4. 4. Hepatic biliverdin reductase activity was 0.086 ±0.016 nmol/mg protein/hr. The synthesis of bilirubin was apparently limited by the enzyme activity. 5. 5. Most of the bilirubin in bile was conjugated (90%) with monoconjugates predominating (75%). 6. 6. Hepatic UDP-glucuronosyl transferase activity was 2.65 ± 0.18 and 1.14 ± 0.16 μmol/mg protein/hr with and without activation, respectively.