Age-related changes in enzymes of rat brain. 2. Redox systems linked to NADP and glutathione

Measurements have been made of the enzymes of glutathione metabolism and of NADPH generation in the brains of rats aged between 1 day and 24 months. The activity of glutathione peroxidase fell while that of glutathione reductase rose during the aging process. The four NADPH-generating systems each showed a different profile with respect to aging, the most marked changes occurring between 1 and 20 days. Subsequently, the systems remained close to, or above, the young adult value. The role of the glutathione-metabolising enzymes in controlling the H2O2 metabolism and suppressing peroxidative damage to the brain is discussed.