[Sensitivity of embryonal lungs of mice, rats and humans to exposure to nitrosomethylurea in organ cultures].

With the direct action of nitrosomethylurea (NMU) in a concentration of 0.05 mg/ml on the organic cultures of the embryonic lung of mice of the A line, Wistar rats and man they developed a different degree of degenerative changes and hyperplastic epithelial proliferates. A toxic effect prevailed in the cultures at the initial experimental periods. The most sensitive to the toxic action of NMU was the lung tissue of rat embryos, and the least--of mice. The incidence of hyperplastic proliferates was, on the contrary, the greatest in the cultures of mouse lungs, and the least--of rat lungs. The sensitivity of the embryonic lungs of the man and rodents to the toxic action of NMU in repeated administration into the nutrient medium diminished during the cultivation. There was an increase of survival of the experimental cultures in comparison with the intact control.