Sequential changes in activities of superoxide dismutase and catalase in brain regions and liver during (-)deprenyl infusion in male rats.

A continuous s.c. infusion of (-)deprenyl in young male rats at a dose of 2.0 mg/kg/day for 1 week significantly increased total superoxide dismutase (SOD) activities due to increases in both Cu Zn-SOD and Mn-SOD activities in certain brain regions such as the substantia nitra and striatum, but not in the hippocampus or cerebellum, or in the liver. With continuing infusion, enzyme activities of SOD were further increased in the following weeks, reaching a plateau at 3 weeks. In some cerebral cortices the increase became significant at 3 weeks. In contrast to SOD activities, an increase in catalase (CAT) activity became significant only after 2 weeks of infusion, and only in the brain regions where SOD activities were increased earlier. The delay in the increase in CAT activity following deprenyl infusion suggests that this increased CAT activity is an adaptive response to the earlier increase in deprenyl-induced SOD activities rather than a direct effect of deprenyl on CAT activity, although the latter possibility cannot be excluded.