Induction of antioxidant enzymes by dexamethasone in the adult rat lung.

Catalase, glutathione peroxidase and superoxide dismutase enzymes were determined after administering dexamethasone. Catalase increased its activity over six times (0.388 U/mg DNA) the normal rate, while glutathione peroxidase caused 3 times an increase one hour after dexamethasone injection. Superoxide dismutase increased gradually during the 3 hour treatment. The antioxidant enzyme activities decreased to basal values in the presence of protein synthesis (Cycloheximide) and RNA synthesis (Actinomycin D) inhibitors. The current report demonstrates that the increase of antioxidant enzymes is due to an enzymatic induction mechanism, and not due to an activation process.