Analysis of Labeling and Clearance of Lung Surfactant Phospholipids in Rabbit: EVIDENCE OF BIDIRECTIONAL SURFACTANT FLUX BETWEEN LAMELLAR BODIES AND ALVEOLAR LAVAGE

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Abstract

Turnover and clearance of lung surfactant phospholipids were studied with particular reference to myoinositol-induced perturbation in the acidic phospholipids. Administration of myoinositol decreased [3H]palmitate and [32P]phosphate incorporation into phosphatidylglycerol by 80-90% in whole lung, and by 94-99% in lamellar bodies and in alveolar lavage. The increased incorporation of radioactive isotopes into phosphatidylinositol following myoinositol, was inverse to the decrease in phosphatidyl-glycerol incorporation. Myoinositol treatment affected neither content nor labeling of phosphatidylcholine or disaturated phosphatidylcholine as studied within 50 h of administration. Phosphatidylglycerol was pulse labeled by intravenous [32P]phosphate and [3H]palmitate, followed by myoinositol. The biological half-lives of phosphatidylglycerol in the microsomal fraction, lamellar bodies, and alveolar lavage were 1.6, 4.6, 5.4 h (with 3H), and 2.8, 6.5, 7.0 h (with 32P), respectively.

Authors

Mikko Hallman, Benita L. Epstein, Louis Gluck