INVESTIGATION OF THE ROLE OF REACTIVE OXYGEN SPECIES IN BILIRUBIN METABOLISM IN THE GUNN RAT

It has been previously established that the attenuation of hepatic lip id peroxidation by a fat-free diet is accompanied by a marked rise in plasma bilirubin in Gunn rats. Present in vitro studies confirmed that microsomal lipid peroxidation caused the concurrent degradation of ad ded bilirubin but failed to show that microsomal superoxide, hydroxyl radical or hydrogen peroxide would degrade bilirubin. Moreover, althou gh injection of vitamin E completely inhibited microsomal lipid peroxi dation and bilirubin degradation it had no effect on plasma bilirubin. No evidence has therefore been obtained that in Gunn rats, in the abs ence of bilirubin glucuronidation, that reactive oxygen species provid e a significant physiological pathway of bilirubin disposal.