Effect of age on superoxide dismutase, catalase, glutathione reductase, inorganic peroxides, TBA-reactive material, GSH/GSSG, NADPH/NADP+ and NADH/NAD+ in Drosophila melanogaster.

The objective of this study was to investigate the possible role of oxygen free radicals in the aging process by studying the pattern of age-related changes in a broad spectrum of antioxidant defenses and indicators of oxidative stress in adult male Drosophila melanogaster. There were selective, but not universal, changes in the antioxidant defenses and indicators of oxidative stress. Activities of catalase and glutathione reductase and concentration of reduced glutathione decreased during the latter part of life. Superoxide dismutase activity tended to increase with age whereas glutathione peroxidase activity was undetectable. The ratios of reduced/oxidized glutathione and NADPH/NADP+, which are widely regarded as indicators of oxidative stress, decreased in the terminal phase of life. NADH/NAD+ ratio increased in the latter part of life. Concentration of inorganic peroxides increased during the first trimester of life and remained unchanged thereafter while that of thiobarbituric acid-reactants tended to decrease during aging. The main conclusion of this study is that age-related changes in antioxidant defenses and in levels of oxygen free radical reaction products are selective in nature and are quite variable in different species and tissues; however, the level of oxidative stress tends to increase during aging.