Anguilla anguilla L. liver EROD induction and genotoxic responses after retene exposure

Anguilla anguilla L. (European eel) were exposed for 8, 16, 24, and 72 h to 0 (control), 0.1, 0.3, 0.9, and 2.7 microM retene. A. anguilla L. liver ethoxyresorufin-O-deethylase EROD activity significantly increased during the whole exposure period to all retene concentrations, when compared to their controls. The liver cytochrome P450 content only increased after exposure to high retene concentrations (0.9 and 2.7 microM) from 8 to 24 and 72 h, respectively. Generally, liver DNA integrity decreased with increased retene concentrations. Thus, a low retene concentration (0.1 microM) was only effective at 16 h, 0.3 and 0.9 microM had an early and prolonged effect up to 24h, and 2.7 microM decreased liver DNA integrity during the whole exposure period. However, blood DNA integrity decrease was observed in eels after 24h exposure to 0.1 microM retene, and at 16 h to 0.3 and 0.9 microM retene, despite an early blood DNA integrity decrease at 8 and 16 h exposure to 2.7 microM retene. An early genotoxic response to retene was also observed as erythrocyte nuclear abnormalities plus Notched (ENA+Not) frequency increase at 8, 16, and 24h exposure to 0.1 and 0.3 microM retene as well as at 8, 16, 24, and 72 h to 0.9 microM retene. Though, the highest retene concentration (2.7 microM) only induced ENA+Not and erythrocyte nuclear abnormalities minus Notched (ENA-Not) at 16 h exposure. The eel ENA+Not increase was more sensitive than the ENA-Not increase as a measure of retene genotoxicity. Eel liver alanine amino transferase (ALT) increased activity reveals its enhanced transamination capacity after short-term exposure to retene. The A. anguilla L. ratio between hemoglobin concentration and red blood cells count (Hb/RBC) increased at 8h exposure to 0.1, 0.3, and 0.9 microM retene, suggesting an initial homeostatic process.