Genotoxicity biomarkers' association with B(a)P biotransformation in Dicentrarchus labrax L

Dicentrarchus labrax (sea bass) were exposed during 0, 4, 8, 16, 24, 48, and 96 h to 0 and 0.1 microM benzo(a)pyrene (B(a)P), an environmental pollutant, and the following biomarkers were measured: (1) liver cytochrome P450 (P450) content and ethoxyresorufin-O-deethylase (EROD) activity as phase I biotransformation parameters, (2) liver gluthathione-S-transferase (GST) activity as a phase II biotransformation conjugation enzyme, (3) biliary and liver cytosolic B(a)P-type metabolites by fixed wavelength fluorescence detection (FF), and (4) erythrocytic micronuclei (EMN) and erythrocytic nuclear abnormalities (ENA) as genotoxicity biomarkers. Liver EROD activity (4 h), P450 content (24 h), GST activity (4, 8, and 96 h), bile (4-96 h), and liver cytosolic (4-24 h) B(a)P-type metabolites increased significantly in sea bass exposed to B(a)P as well as EMN (8-96 h) and ENA (4-96 h) frequencies. B(a)P genotoxicity is associated with increase in B(a)P-type metabolites in liver cytosol due to an impaired phase II conjugation. This increase seems to be responsible for the decrease in liver EROD and GST activities.