[State of the surface activity of pulmonary surfactant in rats at different periods after left-sided pneumonectomy].

The surface activity of the seven-fold washing of the right lung was measured on the modified Wilhelmy's balance after the leftside pneumonectomy in rats. It appeared to be normal (gamma min-23--24 dynes/cm) up to the 5th day, and at the remote postoperative periods. The intracellular edema of the air-blood barrier components and the release of the edema fluid into the alveolar lumen in the "vesicle" composition failed to influence the surface properties of the lung surfactant. A sharp increase of the alveolar dimensions on the 5th--7th postoperative day was followed by an increase of the surface-active properties of the lung washings (gamma-min-11--15 dynes/cm) and by the intensified secretion of the material of the osmiophilic lamellar bodies from the alveolar cells of the 2nd type into the alveolar lumen. The cytological mechanisms providing the intensified production of the surfactant in the hypertrophic alveoli are activation of the lipid synthesis in the alveolar cells of the 2nd type, their hypertrophy, and also the appearance of binuclear cells.