Oxygen-induced changes in pulmonary superoxide dismutase assayed by antibody titrations.

Previous studies have demonstrated a 50% increase in pulmonary superoxide dismutase (SOD) activity in oxygen-adapted rats and have suggested that SOD plays a significant role in the development of "tolerance". To further study these events, the cuprozinc SOD was purified from rat liver and found to be similar to previously purified cuprozinc superoxide dismutases. A rabbit antisera to rat cuprozinc SOD was produced and used to perform antibody titrations of SOD in the lungs of rats exposed to 85% O2 for 5 days. The absolute amount of cuprozinc SOD increased 41% by antibody titration which accounted for most, if not all, of the 48% increase demonstrated in total SOD activity. Spectrophotometric assays at pH 7.8 and 10.0 of pure rat cuprozinc SOD and crude lung homogenates suggest that there is also a manganese SOD present, but the role of that SOD in the development of oxygen tolerance has not been established.