Molecular species of phosphatidylcholine and phosphatidylglycerol in rat lung surfactant and different pools of pneumocytes type II.
It is not yet completely understood how a cell is able to export specific phospholipids, like dipalmitoylphosphatidylcholine (dipalmitoyl-PC), which is secreted by pneumocytes type II, into pulmonary surfactant. The acyl species composition of [3H]PC which was synthesized in type II cells in the presence of [2-3H]glycerol resembled the species composition of PC localized in intracellular pneumocyte membranes. This species pattern was different from the pattern of PC of lamellar bodies, i.e., intracellularly stored surfactant, by a higher proportion of dipalmitoyl-PC mainly at expense of 1-palmitoyl-2-oleoyl-PC. Lamellar body PC in turn showed the same species distribution as surfactant PC. The data suggest that subcellular compartmentation and/or intracellular transfer of PC destined to storage in lamellar bodies, but not secretion of lamellar bodies, involves an enrichment of dipalmitoyl-PC and a depletion of 1-palmitoyl-2-oleoyl-PC. In contrast, the acyl species pattern of phosphatidylglycerol does not seem to undergo gross changes on the path from synthesis to secretion.
Institute of Pathological and Clinical Biochemistry, Charite Hospital, Humboldt University, Berlin, German Democratic Republic.
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M
Schlame
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Casals
B
B
Rüstow
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H
Rabe
D
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Kunze
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D005227:Fatty Acids / Q000032:analysis; D005990:Glycerol / Q000378:metabolism; D066298:In Vitro Techniques; D008168:Lung / Q000166:cytology / Q000378:metabolism*; D008297:Male; D010713:Phosphatidylcholines / Q000032:analysis*; D010715:Phosphatidylglycerols / Q000032:analysis*; D011663:Pulmonary Surfactants / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D005227:Fatty Acids; D010713:Phosphatidylcholines; D010715:Phosphatidylglycerols; D011663:Pulmonary Surfactants; D005990:Glycerol