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(M/EH079) Impact of retene on glutathione metabolism and EROD activity in fish and mussel. Soimasuo, M.R.1, Kujala, S.R.1, Oikari, A.O.J.1, 1 ABSTRACT- The effects of retene (1-methyl-7-isopropylphenanthrene) on glutathione metabolism and EROD activity in rainbow trout (Onchorhynchus mykiss), whitefish (Coregonus lavaretus), and duck mussel (Anodonta anatina) were studied. Retene has been found in elevated concentrations in the sediments of the recipients of pulp and paper mills. Juvenile fish were exposed i.p. to retene concentrations of 10, 33, and 100 mg/kg, and were sampled after four days of exposure. Duck mussels were exposed to contaminated sediments in pulp and paper mill recipient (Lake Saimaa, Finland, retene concentration ~300 mg/kg d.w.) for five months, and in laboratory for three months using same sediments. Liver microsomal EROD activities were induced in retene exposure both in rainbow trout (93-180 -fold) and in whitefish (23-60 -fold) as compared to the control. Simultaneously with the increase in EROD activity, the activity of cytosol glutathione transferase (GST), glutathione peroxidase (GPx) and glutathione reductase (GR) increased at the two lowest exposure concentrations, but slightly decreased at the highest concentration in rainbow trout. In whitefish, however, no significant chances in the activity of these enzymes were observed. In both fish species significant changes in glutathione levels (GSH, GSSG, total GSH, GSH/GSSG) occurred, but the responses were somewhat different between fish species. Glutathione plays a central role in the defense of the cell against oxidative stress. These results suggest that retene may cause oxidative stress in both rainbow trout and whitefish, and that biotransformation of retene is an important factor in the formation of oxidative stress. Samples from mussel exposures, currently being analyzed, will expand the knowledge on these mechanisms in other aquatic organisms. Key words: glutathione, EROD activity, detoxification enzymes, rainbow tro |
