The role of glutathione S-transferases in the hepatic metabolism of benzo[a]pyrene in white suckers ( Catostomus commersoni) from polluted and reference sites in the great lakes

Abstract

1. 1.Orally administered 3H-benzo[a]pyrene ( 3H-BaP) was excreted in the bile of White Suckers predominantly as water soluble metabolites some of which were hydrolyzed by arylsulfatase or β-glucuronidase. 2. 2. Non-hydrolysible polar metabolites comprised a substantial proportion of biliary metabolites. 3. 3. HPLC analysis revealed fluorescent and 3H-labelled peaks which co-eluted with standards of the glucuronide and sulfate conjugates of BaP. 4. 4. The most polar peak co-chromatographed with a double-radiolabelled metabolite produced in vitro with 3H-BaP and 35S-glutathione. 5. 5. Inhibition of epoxide hydrolase in vitro reduced all water soluble metabolites except the glutathione conjugate of BaP. 6. 6. Glutathione conjugation represents a major hepatic detoxication pathway of BaP in White Suckers.