Lecithin content estimate of human alveolar lining layer: comparison with mouse, rat and rabbit

Saturated as well as total lecithins recovered by lung lavage are linearly correlated with the species body weight and with their respiratory rate. The value of the ratio:amount of saturated lecithins recovered by lung lavage to theoretical minimum amount needed to form a monomolecular film over the alveolar surface at functional residual capacity decreases linearly according to the respiratory rate of the species examined. In man this ratio is lower than 1 (0.45 +/- 0.11) and suggests the possible existence of a discontinuous mono molecular film of lipidic surfactant.