[Permeability of components of the air-blood barrier to water evaluated by the radionuclide method].

Permeability of the pulmonary and bronchial endothelium, interstitium and epithelium for triated water was determined on isolated canine lungs. Permeability of alveolar epithelium for water is 2.5-fold lower than that of endothelium, and water mass transfer occurs primarily through molecular diffusion. In the bronchial circulation, diffusion and convection of water takes place, and endothelium is the main site of resistance for water transfer across the air-blood barrier.