Mechanism of arachidonic acid release in human polymorphonuclear leukocytes

Christopher E. Walsh, Lawrence R. Dechatelet, Floyd H. Chilton, Robert L. Wykle, Moseley Waite

Research output: Contribution to journalArticlepeer-review

72 Scopus citations

Abstract

Previous studies have demonstrated that [3H]arachidonic acid is released from prelabeled human neutrophil phospholipids when the cells are stimulated by calcium ionophore A23187 or by opsonized zymosan. Neither lysophospholipid generated by phospholipase A2 activity, diacylglycerol nor monoacylglycerol produced via phospholipase C/diacylglycerol lipase action have been identified following neutrophil challenge. The inability to detect any intermediates during the release of arachidonate is due to either rapid reacylation of lysophospholipid or conversion of diacylglycerol (monoacylglycerol) to cellular acylglycerols. The addition of exogenous [14C]fatty acid at the time of challenge was employed to determine the involvement of either phospholipase A2 or phospholipase C activities. Neutrophil stimulation with calcium ionophore A23187 resulted in an incorporation of exogenous [14C]arachidonate into phosphatidylinositol and phosphatidylcholine, those phospholipids which specifically release arachidonate. When the saturated fatty acid, [14C]stearate, replaced [14C]arachidonate, very little [14C]fatty acid was incorporated into any of the phospholipid species. Lipid phosphorus measurements revealed no significant mass change in any phospholipid class following ionophore challenge. Production of [14C]phosphatidic acid was not detected, as would be expected if diacylglycerol kinase and de novo phospholipid metabolism were significantly involved.

Original languageEnglish (US)
Pages (from-to)32-40
Number of pages9
JournalBiochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism
Volume750
Issue number1
DOIs
StatePublished - Jan 7 1983
Externally publishedYes

Keywords

  • (Human leukocyte)
  • Arachidonic acid
  • Hydroxyeicosatetraenoic acid
  • Phospholipase A
  • Phospholipid synthesis
  • Reacylation

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Endocrinology

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