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Mixed‐function oxidase enzyme activity and oxidative stress in lake trout ( Salvelinus namaycush ) exposed to 3,3′,4,4′,5‐pentachlorobiphenyl (PCB‐126)
Author(s) -
Palace Vince P.,
Klaverkamp Jack F.,
Lockhart W. Lyle,
Klaverkamp Jack F.,
Lockhart W. Lyle,
Metner Don A.,
Muir Derek C. G.,
Brown Scott B.
Publication year - 1996
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620150618
Subject(s) - trout , antioxidant , chemistry , oxidative stress , superoxide dismutase , glutathione peroxidase , catalase , salvelinus , ascorbic acid , thiobarbituric acid , medicine , endocrinology , retinol , vitamin , biochemistry , lipid peroxidation , food science , biology , fishery , fish <actinopterygii>
Juvenile lake trout were intraperitoneally injected with corn oil containing nominal concentrations of 0, 0.6, 6.3, or 25 μg [ 14 C]‐3,3′,4,4′,5‐pentachlorobiphenyl (PCB‐126) per gram of body weight. The PCB‐126 accumulated in liver in a dose‐dependent manner to a sustained concentration by 6 weeks and remained elevated for the 30‐week experimental period. Mixed‐function oxidase (MFO) enzyme activity was elevated in the two highest dose groups relative to the control group, but not in the low‐dose group throughout the 30 weeks. Oxidative stress, measured by the thiobarbituric acid reactive substances test, was correlated with ethoxyresorufin O ‐deethylase and was elevated in liver of the two highest PCB dose groups but not the low‐dose group. The activities of the enzymatic antioxidants superoxide dismutase, catalase, and glutathione peroxidase were unaffected by PCB‐126 exposure. The nonenzymatic antioxidant tocopherol was depleted to approximately 75% of the control concentration in liver of all three PCB‐dosed groups. Hepatic ascorbic acid levels were not different in any of the treatment groups. Retinol was depleted by greater than an order of magnitude in liver of the two highest dose groups but not in the low‐dose group. This study demonstrates a correlation between hepatic MFO activity and oxidative stress in PCB‐exposed lake trout. Tocopherol and retinol may be important mediators of oxidative stress but additional study is required to confirm the antioxidant activity of retinol.