Isozyme selective induction of mouse pulmonary superoxide dismutase by the exposure to mercury vapor

Alterations in lung superoxide dismutase (SOD) isozymes after exposure of mice to mercury vapor were examined. Inhalation of mercury vapor (10 mg/m(3)) for 1 h by mice resulted in a higher accumulation of mercury in the kidney and lung compared to other organs, at 1 h after exposure. Under these conditions marked enhancement of protein content in bronchoalveolar fluid (BALF), attributed to lung injury, was observed. Exposure to mercury vapor caused a significant increase in the pulmonary Cu,Zn-SOD activity (1.32-fold at 48 h) whereas Mn-SOD activity was suppressed to 82% of the control level, suggesting different sensitivity to the metal inhalation. The selective induction of Cu,Zn-SOD protein (1.79-fold at 48 h) was confirmed by immunoblot analysis with polyclonal antibodies against these isozymes. These observations suggest that the selective induction of Cu,Zn-SOD at the translational level appears to occur as an initial defense against mercury-promoted oxidative stress.