Surfactant metabolism of newborn lamb lungs studied in vivo.
Surfactant, microsomal, and lamellar body fractions were isolated from the lungs of 5-day-old lambs 0.21-55 h after the intravenous injection of radiolabeled palmitic acid. The specific activities as cpm/mumol phospholipid phosphate of phosphatidylcholine, saturated phosphatidylcholine, phosphatidylglycerol, and phosphatidylethanolamine were measured. The palmitate-labeled phospholipids disappeared from the lung parenchyma with a half-life of approximately 50 h. The radiolabel disappeared from phosphatidylcholine, saturated phosphatidylcholine, phosphatidylglycerol, and phosphatidylethanolamine of microsomal fractions with initial half-life values of 4.5, 4.6, 1.9, and 23.9 h, respectively. The labeled phospholipids rapidly appeared in the lamellar body fraction and accumulated in the surfactant of the lambs in a linear fashion for 35 h. The curves for the labeling of surfactant with radiolabeled saturated phosphatidylcholine, phosphatidylglycerol, and phosphatidylethanolamine were similar to the curve for phosphatidylcholine.
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D005260:Female; D050356:Lipid Metabolism; D008168:Lung / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000378:metabolism; D010714:Phosphatidylethanolamines / Q000378:metabolism; D010715:Phosphatidylglycerols / Q000378:metabolism; D011247:Pregnancy; D011663:Pulmonary Surfactants / Q000378:metabolism*; D012756:Sheep / Q000378:metabolism*
D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D010715:Phosphatidylglycerols; D011663:Pulmonary Surfactants