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.
Schlame
M
M
Institute of Pathological and Clinical Biochemistry, Charite Hospital, Humboldt University, Berlin, German Democratic Republic.
Casals
C
C
Rüstow
B
B
Rabe
H
H
Kunze
D
D
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