Selenium-dependent glutathione peroxidase activity is documented for the first time in insects. Reduction in glutathione peroxidase activity in the cytosol of adult house flies by lowering selenium in the diet results in significant increases in peroxidative injury. Catalase activity, while higher in low-selenium flies than in selenium-supplemented flies, does not prevent lipid peroxidation. The discovery of glutathione peroxidase activity in insects eliminates an anomaly which partially limited the usefulness of these animals as models for the study of the antioxidant defense system.
