Acute effects of benzo[a]pyrene on liver phase I and II enzymes, and DNA damage on sea bream Sparus aurata

In the present study biotransformation and detoxification responses to acute exposure to the polycyclic aromatic hydrocarbons benzo[a]pyrene (B[a]P) were investigated in the liver of Sparus aurata (sea bream). Sexually immature gilthead sea bream were treated by intraperitoneal injection of B[a]P (20 mg kg(-1)) for 6, 12, 24, and 48 h. B[a]P accumulation was quantified in sea bream liver by mean of gas phase chromatography (GPC-MS) after the various exposure periods. The following biological responses were measured: (1) ethoxyresorufin-O-deethylase (EROD) activity, as a phase I biotransformation parameter; (2) liver glutathione S-transferase (GST) activity as a phase II conjugation enzyme. DNA damage was assessed over time using the single-cell gel electrophoresis comet assay. B[a]P bioaccumulation in the liver resulted in a biphasic curve with an increasing uptake up to 5.55 +/- A 0.67 mu g g(-1) dry weight after only 6 h exposure and 4.67 +/- A 0.68 mu g g(-1) dry weight after 48 h exposure. EROD activity showed a nonsymmetrical bell-shaped kinetic with a maximum at 24 h and lower but significant activities at 12 and 48 h with respect to control animals. Hepatic GST activities were only significant after 48 h exposure. Comet assay showed an increase in liver cells DNA damage with a maximum after 48 h exposure reaching up to 12.17 %DNA in the tail.