Surface active materials from dog lung. II. Composition and physiological correlations

TLDR: All four fractions exhibited the surface properties expected of pulmonary surfactant, as judged by their low surface tensions, quantitative spreading in the air-liquid interface, surface compressibilities, and adsorption kinetics.

Abstract: KING, RICHARD J., AND JOHN A. CLEMENTS. Surface actiue materials from dog lung. 11. Composition and physiological correlations. Am. J. Physiol. 223(3) : 715726. 1972.-We studied the chemical composition and physical properties of the four surface active materials obtained from dog lung. All were composed of lipid and protein and contained less than 2y0 hexose and hexosamine. The four fractions differed from each other in protein content, but did not differ significantly in lipid composition. The protein to phosphorus ratio and surface properties of one of the surface active materials, WI, were the same after isoelectric focusing in a pg gradient. All four fractions exhibited the surface properties expected of pulmonary surfactant, as judged by their low surface tensions, quantitative spreading in the air-liquid interface, surface compressibilities, and adsorption kinetics. Sufficient amounts of these materials were recovered to cover the estimated alveolar surface area more than 2 times. As compared with the lipids of other lung components, all were enriched 4-6 times in dipalmitoyl phosphatidylcholine. The physiological functions of the four fractions are not clear, although they might represent intraand extracellular materials in different stages of elaboration.