METABOLISM OF PULMONARY PHOSPHOLIPIDS IN NORMAL LUNG AND DURING ACUTE PULMONARY EDEMA

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Abstract
When radiolabeled (C14 and H3) palmitic and oleic acids were injected intravenously into normal dogs, the fatty acids were quickly incorporated into pulmonary lipids. Incorporation was 4 times as rapid for palmitic as for oleic acid, and occurred principally into phospholipids, lecithin and phosphatidyl ethanolamine, and into trigly-ceride. Following induction of pulmonary edema by intravenous infusion of dextran, there was a significant decrease in total phospholipid and in the radioactivity of phospholipids. The loss of phospholipids was nonselective. Radioactivity was present in the pulmonary edema fluid and its characteristics suggested a mixed origin from pulmonary phospholipid and plasma. Atelectatic areas of edematous lung, having decreased surface activity, also showed significantly less phospholipid and tissue radioactivity than aerated areas. The observations are compatible with an important role for phospholipids, particularly lecithin, in preventing alveolar collapse, and shed some light on the dynamics of pulmonary lipids on the intact animal and during acute pulmonary edema.