<Original Report>STUDIES ON FACTORS INFLUENCING STABLE BUBBLE FORMATION FROM LUNG HOMOGENATE

Abstract

A simple in vitro way of examining materials interfering with the formation of stable bubbles from lung surfactant was presented. The method consists of agitation of liquid extracts with a magnetic stirrer for l hr and examination of bubble stability under a microscope. Bubble stability of perfused lung homogenate from adult rat was significantly greater than that which was not perfused. Foams from isolated surface-active material and lung homogenate of fetal rat showed high stability but those from adult rat lung homogenate showed low stability. In analysis of lipid composition by thin layer chromatography, no significant differences were found among foams from various extracts and fractions from purification steps of surfactant in spite of much difference among the extracts and fractions themselves. Contamination with materials, which were precipitated by sucrose gradient ultracentrifugation of adult rat lung homogenate at 48, 000g, inhibited stable bubble formation in half-purified surface-active material from adult rat lung and in fetal lung homogenate. From these results, it is suspected that inhibiting factor (s) are present in adult rat lung homogenate which interfere with stable bubble formation from surfactant, even if the surfactant itself is sufficient in amount.