[Enzymes utilizing hydroperoxides and O ./2 in the myocardium of rats of different ages]

Superoxide dismutase activity of myocardial cytosol increases with rat age (1, 3, 12, 24 months) whereas catalase activity is unchanged. Glutathione peroxidase activity with H2O2, cumene and t-butyl hydroperoxides as substrates increases more than 1.5-fold over the period from 1 to 12 months. The high activity of these enzymes is maintained in 24-month-old rats.