Phospholipases A1 and A2 in lamellar inclusion bodies of the alveolar epithelium of rabbit lung.

1. A lamellar body-enriched fraction was prepared from rabbit lung and characterized by electron microscopy, surface activity studies, phospholipid assay and marker enzymes. 2. Both phospholipases A1 and A2 were found to be present in lamellar bodies. After these had been ruptured both enzymes were found to be principally in the soluble phase. 3. The possible roles for phospholipases in lamellar body development and in the respiratory distress syndrome of the newborn are discussed.