Response of antioxidant enzymes in freshwater fish populations( Leuciscus alburnoides complex) to inorganic pollutants exposure

Evidence is accumulating indicating the importance of antioxidant enzyme ac tivity measurements in eco-toxicological studies, as they may constitute ma rkers for exposure to a large variety of pollutants. Variation of antioxida nt enzymes, superoxide dismutase (SOD) and glutathione S-transferases (GST) and the effect of heavy metals and selenium exposure on these enzymes were investigated in the livers of Iberian endemic minnows (Leuciscus alburnoid es complex) captured in a copper (Cu) mining area. Higher hepatic levels of copper and selenium were always observed in fish captured at the polluted site relative to the reference area population, reflecting the environmenta l monitoring results. A seasonal fluctuation in zinc and selenium levels fo r both populations was also observed which could be related to gonad matura tion. The activity of SOD did not show significant regional alterations, bu t a seasonal variation occurred presumably associated with the Leuciscus li fe cycle. The GST activity was higher in the fish population from the pollu ted area (except in spring) and GST variability was associated with seleniu m and copper levels when both regions were compared. The increased GST acti vity was probably a metabolic adaptation to the continuous exposure to high er levels of those elements. (C) 2001 Elsevier Science B.V. All rights rese rved.