title: Endogenous antioxidant systems of two teleost fish, the rainbow trout and the black bullhead, and the effect of age.
abstract: Antioxidant enzyme activities and glutathione status were determined in different tissues of two teleost species, the rainbow trout (Oncorhynchus mykiss) and the black bullhead (Ameiurus melas) to establish whether age-related changes exist between mature and immature individuals. Glutathione reductase and superoxide dismutase activities were significantly lower in hepatic and extrahepatic tissues of 3+ year than 1+ year trout and bullheads. Activities of glutathione peroxidase, catalase and glutathione S-transferase did not exhibit a clear pattern, with decreases in liver and kidney, but increases in gill and muscle tissues. Glutathione concentrations were significantly higher in most tissues of 3+ year than in 1+ year trout, but remained unchanged or decreased in tissues of older bullheads. The results imply an age- or maturation-dependent effect on key antioxidant enzymes in various tissues of these 2 teleost species. Thus, age and maturation may impact upon the use of oxidative stress parameters as indicators of contaminant exposure in environmental studies.
authors.affiliation: Ottawa-Carleton Institute of Biology, Department Biology, University of Ottawa, P. O. Box 450 Stn A, K1N 6N5, Ottawa, Ontario, Canada.
authors.forename: D M
authors.initials: DM
authors.lastname: Otto
authors.forename: T W
authors.initials: TW
authors.lastname: Moon