Inhibition of surfactant release from isolated type II cells by compound 4880

Abstract Release of [ 3 H]phosphatidylcholine from pulmonary Type II epithelial cells was stimulated by terbutaline, forskolin and cytochalasin D. Compound 48 80 inhibited both basal and agonist-stimulated release of [ 3 H]PC. The IC 50 for inhibition by compound 48 80 was 1–2 μg/ml, and was similar for inhibition of both basal and stimulated release of [ 3 H]phosphatidylcholine. Inhibitory effects of 48 80 were noted following a 1 h exposure to compound 48 80 and persisted up to 3 h. The inhibitory effect of compound 48 80 was entirely reversed by removing compound 48 80 from the external milieu. Compound 48 80 had no effect on cytosolic cyclic AMP levels or lactate dehydrogenase release. Inhibition of surfactant release produced by compound 48 80 was unaffected by changes in extracellular calcium concentrations. Compound 48 80 is a non-toxic inhibitor of phosphatidylcholine release from Type II epithelial cells.