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 PARENT SESSION
1D Bioassays for specific hazards (estrogenic effects, genotoxicity, neurotoxicity, ...)
9:00 AM to 7:00 PM, Tuesday, 08 May 2001
(T/EH082) Comparative study of PAH and PAH-like compounds as liver biotransformation and erythrocytic genotoxic inducers.
Gravato, C.1, Santos, M.A.1, 1
ABSTRACT- This research work concerns the comparative study of polynuclear aromatic hydrocarbons (PAH) and PAH-like compound effects on juvenile sea bass, as liver EROD induction and erythrocytic genotoxicity. Sea bass were exposed during 0, 2, 4, 6 and 8 hours either to 0 and 2.7  M  -naphthoflavone (BNF, PAH-like compound) or to 0, 0.1, 0.3, 0.9 and 2.7 M benzo(a)pyrene (B(a)P) and naphthalene (N) (PAHs). Liver ethoxuresorufin-O-deethylase (EROD) induction was determined as phase I biotransformation response, whereas erythrocytic micronuclei (EMN) and erythrocytic nuclear abnormalities (ENA) tests were performed to assess genotoxicity. The comparative analysis of the 3 compounds as EROD inducers indicated BNF as the most potent (9-fold increase at 6 hours exposure), followed by B(a)P (4-fold increase at 6 hours), and N with a negligible effect. Comparative analysis of BNF, N and B(a)P as genotoxic compounds indicated B(a)P as the most potent EMN and ENA inducer (24- and 2.2-fold increase at 2 hours exposure, repectively), and BNF (8- and 1.5-fold increase at 8 hours, respectively). Global results suggest that: (1) low levels of phase I biotransformation enzymes are able to produce the necessary amount of B(a)P and N metabolites, needed to induce genotoxicity; (2) the lack of EROD induction does not always reflects the absence of contamination. Therefore, indicating that the analysis of several biomarkers is requested to assess the effects of environmental contaminants.
Key words: PAHs, EROD, genotoxicity, sea bass
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