Effects of exogenous antioxidants on the levels of endogenous antioxidants, lipid-soluble fluorescent material and life span in the housefly, Musca domestica

Abstract

Effects of exogenous antioxidant administration (0.5% and 2% ascorbate, β-carotene and α-tocopherol in sucrose) on life-span, metabolic rate, activities of superoxide dismutase and catalase, levels of glutathione, inorganic peroxides and chloroform-soluble fluorescent material (lipofuscin) were examined in adult male houseflies. Administration of antioxidants at a level of 0.5% did not affect life-span, whereas, 2% ascorbate and α-tocopherol decreased average life-span. Metabolic rate of flies was unaffected, except by 2% ascorbate, which caused a decrease. Superoxide dismutase activity was depressed by 2% ascorbate at all ages, and by β-carotene and α-tocopherol in older flies. Catalase activity was unaffected except by α-tocopherol at younger ages. Glutathione concentration was decreased by ascorbate and β-carotene at both concentrations administered. Inorganic peroxides (H 2O 2) were increased by 2% β-carotene and α-tocopherol. Only high concentrations of ascorbate and β-carotene decreased the level of soluble fluorescent material. Results suggest that administration of exogenous antioxidants causes a compensatory depression of endogenous defenses