We plan to investigate physiologic and pharmacologic control of the synthesis, storage and secretion of dipalmitoyl phosphatidylcholine in rat lung. For this purpose we use radiolabelled palmitic acid injected at several incubation times before sacrifice, and analyze saturated lecithin in lung tissue, alveolar lavage fluid, and macrophages washed from the lung. BIBLIOGRAPHIC REFERENCES: Fisher, H.K.: Paraquat Disturbs Metabolism of Dipalmitoyl Phosphatidylcholine in Lungs of Intact Rats. To be published in Clin. Res. 24:000, 1976. Fisher, H.K., Clements J.A., Tierney D.F., and Wright R.R.: Pulmonary Effects of Paraquat in the First Day after Injection. Amer. J. Physiol. 228:1217-1223, 1975.