OXIDATIVE STRESS IN LAKE STURGEON (ACIPENSER-FULVESCENS) ORALLY EXPOSED TO 2,3,7,8-TETRACHLORODIBENZOFURAN

Juvenile lake sturgeon were orally dosed with gelatin containing nomin al concentrations of 0, 0.16 or 1.6 ng [H-3]-2,3,7,8-tetrachlorodibenz ofuran (TCDF) kg(-1) fish weight. Liver, kidney and blood were collect ed 10 and 27 days after exposure. Phase I mixed-function oxidase (MFO) and Phase II (glucuronyltransferase) enzyme activities were determine d in liver. Concentrations of non-enzymatic (tocopherol, retinoids) an d enzymatic (superoxide dismutase, catalase, glutathione peroxidase) a ntioxidant parameters were also quantified in liver and kidney. TC DF concentrations were elevated in liver and kidney of both dose groups a t 10 and 27 days. Lower tissue concentrations of TCDF at 27 days, comp ared with 10 day exposures, as well as the presence of polar metabolit es in bile, may indicate rapid metabolism and clearance of the contami nant. MFO enzyme activity, measured as ethoxyresorufin-O-deethylase (E ROD), was induced in liver with activity at the two sample periods ref lecting the TCDF concentrations. Greater concentrations of hepatic lip id peroxides in both dose groups, indicate that oxidative stress was p roduced by contaminant exposure and/or induced metabolism enzyme activ ity.