TY - JOUR
T1 - Mechanism of arachidonic acid release in human polymorphonuclear leukocytes
AU - Walsh, Christopher E.
AU - Dechatelet, Lawrence R.
AU - Chilton, Floyd H.
AU - Wykle, Robert L.
AU - Waite, Moseley
N1 - Funding Information:
This work was supported by United States Public Healt Service Research Grants AI-10732, AM-11799 and AI-17287, and Oncology Research Center Grant CA-121 97 from the National Cancer Institute. We thank Denise Maclachlan and Tom-mye Campbell for editorial assistance and typing, and Michael Samuel for excellent technical assistance.
PY - 1983/1/7
Y1 - 1983/1/7
N2 - 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.
AB - 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.
KW - (Human leukocyte)
KW - Arachidonic acid
KW - Hydroxyeicosatetraenoic acid
KW - Phospholipase A
KW - Phospholipid synthesis
KW - Reacylation
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U2 - 10.1016/0005-2760(83)90201-1
DO - 10.1016/0005-2760(83)90201-1
M3 - Article
C2 - 6402027
AN - SCOPUS:0020681283
SN - 0005-2760
VL - 750
SP - 32
EP - 40
JO - Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism
JF - Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism
IS - 1
ER -