The assay for catalase is based on the peroxidatic activity of the enzyme. The glutathione peroxidase and reductase assays measure the consumption of NADPH following the reduction of t-butyl hydroperoxide and oxidized glutathione, respectively. The assay for superoxide dismutase is based on the reduction of cytochrome c. All assays utilize the Cobas FARA clinical automated analyzer and provide considerable time savings over the manual assays. o ISSO Academic Press, Inc.
Products of oxygen reduction can lead to free radical mediated reactions in the cell with toxic consequences. Under normal circumstances the levels of reduced oxygen products are low enough to be effectively removed by the natural defense mechanisms of the cell. There are many compounds, however, that enhance the production of oxygen radicals to such an extent that cellular defenses are overwhelmed, and the cell is injured. To establish the mechanism of toxicity as oxygen radical mediated, there are a number of direct and indirect methods. Direct methods include the measurement of superoxide, hydrogen peroxide, or hydroxyl radical. These species are very reactive and their quantitation can be difficult. Therefore, indirect methods of study are often used. One ' The opinions, interpretations, and conclusions contained in this report are those of the authors and do not reflect the views of the Department of the Army. In conducting the research described in this report, the investigation adhered to the NIH's "Guide for the Care and Use of Laboratory Animals." * To whom correspondence should be addressed.