Oxidative stress and endocrine endpoints in white sucker (Catostomus commersoni) from a river impacted by agricultural chemicals.

The effects of agricultural chemicals on cortisol secretion, antioxidants, and lipid peroxidation were investigated in hepatic and adrenal tissue of white sucker (Catostomus commersoni) from a river (Yamaska) that drains an agricultural region in Québec (Canada). Plasma cholinesterase (ChE) activity, used as a biomarker of exposure to pesticides, was elevated in fish from the reference site compared to fish from the contaminated sites. Plasma concentrations of cortisol and thyroid hormones (T3 and T4) were higher in fish from the reference site compared to contaminated sites; reduced glutathione (GSH) levels, catalase (CAT), and glutathione peroxidase (GPx) activities were higher and lipid peroxidation (LPO) was lower. Levels of antioxidants (CAT, Gpx, and GSH) were higher (10-90%) and LPO levels were lower (50%) in the liver than in the adrenal tissue. The present in situ study provided evidence that antioxidants, lipid peroxidation, and plasma hormones were altered in fish sampled in areas impacted by agricultural chemicals. Endocrine-disrupting effects were associated with oxidative stress. The results suggest that antioxidants and lipid peroxidation could be used as markers of contaminant exposure in fish.