Effect of supplementation with Cu and Zn on antioxidant enzyme activity in the rat tissues

The activities of antioxidant enzymes-copper. zinc- and manganese-superoxide dismutase (CuZnSOD and MnSOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione S-transferase (GST) and glutathione reductase (GR)-were examined in the liver, heart, small intestine and brain, after supplementation with chelated forms of Cu and Zn. In the supplemented animals increased activity of CuZnSOD were found in the liver and heart. Activity of MnSOD and GSH-Px in the heart and GSH-Px in small intestine was decreased. After 43 days of Cu and Zn supplementation no changes in enzymes activity in the rats brain were found. The increased CuZnSOD activity in liver and heart after supplementation may be due to increased levels of the accumulation of excess Cu and Zn in these tissues. Decreased activity of other antioxidant enzymes could be the consequence of establishing a new antioxidant homeostasis, as Zn and Cu may act as antioxidants. (C) 2002 Elsevier Science Ltd. All rights reserved.