The effect of glucocorticoids on the activity of monoamine oxidase, copper-zinc superoxide dismutase and catalase in the rat hypothalamus.

The activities of biogenic amine deaminating enzymes, monoamine oxidase (MAO), types A and B, copper-zinc superoxide dismutase (CuZnSOD) and hydrogen peroxide (H2O2) scavenging enzyme, catalase, were studied in the hypothalamus of rats treated with dexamethasone (DEX) and corticosterone (CORT) for 2 and 7 days. Only chronic treatment (7 days) with both glucocorticoids (DEX -0.2 mg/kg b.w., i.p. and CORT -5 mg/kg b.w., i.p.) produced a significant decrease in hypothalamic MAO-A and MAO-B activities. Under the same conditions DEX induced significant decrease in hypothalamic catalase and CORT in CuZnSOD activities. The results suggest that the effect of both glucocorticoids on MAO activities seems to be mediated by the same mechanisms, while this is not the case with antioxidant enzymes, catalase and CuZnSOD.