[The pulmonary toxicity of mercury vapors in the rat].

Rats have been exposed for periods of 120 to 240 minutes to an atmosphere containing 6 +/- 0.7 mg per cu.m mercury vapor. All rats developed an acute respiratory distress which lead to death within 2 to 210 hours (mean 53.5 h). Microscopical examination of the lungs showed an oedema rich in fibrin, an epithelial necrosis, hyaline membranes and in two cases an interstitial fibrosis. Mercury levels in the lungs ranged between 0.5 and 9.37 micrograms per gramme wet weight. The activity of pulmonary superoxide dismutase was decreased to 1.57 +/- 0.66 micrograms per mg of soluble proteins, compared with the level of 5.01 +/- 0.76 micrograms per mg in control rats. This study confirm the pulmonary toxicity of mercury vapors observed in human intoxication.