Ionophore-induced metabolism of phospholipids and eicosanoid production in porcine aortic endothelial cells: selective release of arachidonic acid from diacyl and ether phospholipids.
Confluent cultures of porcine aortic endothelial cells were prelabeled with 1 microM [14C]arachidonic acid complexed to 1 microM bovine serum albumin. After washing, the cells were stimulated with 1 microM A23187 for time intervals between 30 s and 30 min. Cellular lipids were extracted and separated into major lipid classes and phospholipid subclasses. The external medium was analyzed for released radioactive eicosanoids. The time-course of total release of 14C radioactivity demonstrated a biphasic nature of A23187-induced changes in endothelial cell lipids. Early, from 30 s to 5 min, substantial losses of [14C]arachidonic acid from diacylphosphatidylethanolamine and phosphatidylinositol, as well as an abrupt increase in diacylphosphatidylcholine-associated radioactivity were observed. These initial changes coincided with the release of 14C-labeled cyclooxygenase products. Later changes (5-30 min) included a sustained progressive loss of 14C radioactivity from alkenyl (alk-1-enyl) acylphosphatidylethanolamine and diacylphosphatidylcholine. These later changes coincided with the elaboration of 14C-labeled lipoxygenase products. Although unequivocal assignments cannot be made, the data suggest that specific pools of arachidonic acid provide precursors for individual classes of eicosanoids.
D015121:6-Ketoprostaglandin F1 alpha / Q000096:biosynthesis; D000215:Acylation; D000818:Animals; D001013:Aorta, Thoracic; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism*; D000001:Calcimycin / Q000494:pharmacology*; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D004987:Ethers / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis*; D006893:Hydroxyeicosatetraenoic Acids / Q000096:biosynthesis; D007700:Kinetics; D010713:Phosphatidylcholines / Q000378:metabolism; D010714:Phosphatidylethanolamines / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism*; D013552:Swine
D001095:Arachidonic Acids; D004987:Ethers; D005231:Fatty Acids, Unsaturated; D006893:Hydroxyeicosatetraenoic Acids; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D010716:Phosphatidylinositols; D010743:Phospholipids; D016718:Arachidonic Acid; D000001:Calcimycin; C022022:5-hydroxy-6,8,11,14-eicosatetraenoic acid; D015121:6-Ketoprostaglandin F1 alpha; C025984:15-hydroxy-5,8,11,13-eicosatetraenoic acid