The effects of 96 h exposure to Cr
6+ (added as potassium dichromate) on the status of antioxidant defenses and markers of oxidati
ve damage were e
valuated in three tissues of goldfish,
Carassius auratus. Fish exposure to high dichromate concentrations, 10 and 50 mg/l, increased protein carbonyl le
vels in brain and li
ver, but not in kidney. Chromium exposure also increased concentrations of lipid peroxides in brain (at 5 mg/l) and li
ver (10 mg/l), but not in kidney. The concentrations of reduced glutathione (GSH) were higher in the li
ver of goldfish treated with 5–50 mg/l Cr
6+ than in controls, but in kidney only the 5 mg/l-treated group showed increased GSH le
vels. Dichromate at 1 mg/l increased the concentration of oxidized glutathione (GSSG) in li
ver and kidney by 80 % and 60 % , respecti
vely, whereas at 10 and 50 mg/l the le
vels of GSSG decreased by 50 % in kidney. These results indicate that the dichromate concentrations used induced oxidation of lipids and proteins in goldfish tissues in a concentration- and tissue-specific manner. Also, the redox status of fish tissues was affected in a concentration- and tissue-specific manner. The acti
vities of glutathione reductase increased in all three tissues in response to dichromate treatment, increasing by
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vert, similar"" title=""not,
vert, similar"" border=""0"">2-fold in brain and li
ver in goldfish treated with 50 mg/l Cr
6+. Dichromate treatment did not change the acti
vities of SOD, catalase or GST in brain, but reduced the acti
vities of SOD in li
ver and kidney, and catalase in li
ver. The results suggest that the glutathione system may be responsible for protecting against the deleterious effects of dichromate in fish and indicate the possible de
velopment of an adapti
ve response during the 96 h treatment with the toxicant.