BIOAVAILABILITY AND BIOTRANSFORMATION OF H-3 BENZO[A]PYRENE METABOLITES IN IN-SITU INTESTINAL PREPARATIONS OF UNINDUCED AND BNF-INDUCED CHANNEL CATFISH

The systemic bioavailability and intestinal biotransformation of dieta ry [G-H-3]-3-hydroxy-benzo[a]pyrene (30H-BaP), benzo[a]pyrene [G-H-3]- 9-sulfate (BaP-9-SO4) and 9-benzo[a]pyrenyl [G-H-3]-beta-D-glucopyrano siduronic acid (BaP-9-Glu) were evaluated using an in situ isolated pe rfused intestinal segment of the catfish. 30H-BaP (2 and 20 mu M), BaP -9-SO4 (10 and 40 mu M) or BaP-9-Glu (10 and 40 mu M) solutions were a dministered via micelles into the isolated intestinal segment of non-i nduced and beta-naphthoflavone (10 mg/kg diet) induced catfish. Follow ing a 60 min perfusion, the efferent blood, intestinal contents and mu cosa were analysed for [H-3] content and metabolite profiles. BNF admi nistration did not result in any significant effect upon the transport or metabolism of BaP-9-SO4, BaP 9-Glu or 30H-BaP. The appearance of r adioactivity in all analysed components for all compounds followed a d ose-dependent relationship which was modified by bioavailability and b iotransformation. BaP-9-SO4 and BaP-9-Glu were readily transported int act from the intestinal lumen to the systemic circulation. 30H-BaP was extensively biotransformed to BaP-3-SO4 and lesser amounts of BaP-3,6 -dione and BaP-3-gluculonide before being absorbed into the blood. The se findings support the hypothesis that preconsumptive metabolites and their intestinal biotransformation products are readily available to the systemic circulation of a consumer. Copyright (C) 1996 Elsevier Sc ience Ltd