Protein leakage in the lungs of mice exposed to 0.5 ppm nitrogen dioxide

Forty-four mice were continuously exposed to 0.47 ppm nitrogen dioxide for ten, 12, and 14 days. The protein content of homogenized lung tissue was assayed fluorometrically after the animals had received intravenous injections of fluorescamine, a new reagent for protein assay. The mean protein value of all exposed animals was higher than that of the control animals (P less than .025). No correlation was noted between serum fluorophor levels and those in the lung homogenate.