Age and GSH metabolism in rat cerebral cortex, as related to oxidative and energy parameters

A comprehensive study on GSH metabolism in relation to some markers of oxidative and energy status in rat cerebral cortex as a function of age was performed. Reduced GSH, total GSH and the GSH Redox Index decreased both during growth (defined as the period between 1 and 5 months) and during aging (defined as the period between 5 and 27 months) while GSSG levels increased during the two periods, but most significantly during aging. Also GSH-associated enzymes and adenine-pyridine nucleotide levels show age characteristic changes. The obtained results suggest that decreases in oxidative and energy metabolism occur during aging. They probably contribute to decreases in the activity of the biosynthetic processes (i.e., NADP+(H) and GSH synthesis) and in the antioxidant capacity of the GSH system. However, the oxidative stress does not seem to be a typical characteristic of the aging period; as an oxidative status is present during the growth period too. Typical parameters of aging process are mainly the low levels of reduced GSH, total GSH and GSH Redox Index and the high levels of GSSG as well as the high levels of GSH peroxidase and GSH transferase and the low levels of gamma-glutamylcysteine synthetase.