Physiological responses of Carassius auratus to ytterbium exposure

Physiological and biochemical perturbations in the liver of Carassius auratus were investigated in vivo following 40 days of exposure to ytterbium solutions of different concentration. Glutamate-pyruvate transaminase (GPT) activity in goldfish liver was stimulated at 0.05 mg/L Yb3+ and inhibited at higher Yb3+ concentrations. Activity of the antioxidant enzyme superoxide dismutase (SOD) was stimulated at Yb3+ higher than 0.05 mg/L, and catalase (CAT) activity was strongly inhibited after 40 days of exposure. Detoxifying enzymes glutathione S-transferase (GST) and glutathione peroxidase (GSH-Px) were stimulated at 0.05 mg/L and inhibited at 0.1 mg/L after 40 days of exposure. Among the parameters determined, CAT in goldfish liver was most sensitive to Yb3+, indicating that CAT might be considered a potential tool in the biomonitoring of exposure to Yb3+ in an aquatic ecosystem. (C) 2002 Elsevier Science (USA).