Accumulation of phosphatidic acid mass and increased de novo synthesis of glycerolipids in platelet-activating-factor-activated human neutrophils.
Incubation of human neutrophils with 100 nM-platelet-activating factor (PAF) but without cytochalasin B resulted in a rapid (5 s) accumulation (1.6-fold) of phosphatidic acid (PtdOH) mass. The increased PtdOH mass reached a maximum (2.8-fold) at 1 min and remained elevated (1.7-fold) at 10 min. No methylamine-stable lyso-PtdOH was detectable in the total lipid extract from control or from PAF-activated cells, suggesting that diacyl-PtdOH was the predominant species. In PAF-activated cells, changes in 1,2-diacylglycerol (DG) mass were not detectable at 5 or 15 s. Increased DG mass (1.7-fold) was detected between 30 s and 2 min, but then it declined to basal levels by 10 min. PAF enhanced [3H]glycerol incorporation into PtdOH and DG by 2- and 3-fold respectively during 1-10 min incubations. PAF also increased the radioactivity but not the mass of phosphatidylinositol and of choline glycerophospholipid by 8-fold and 4-fold respectively at 10 min. In addition, PAF-activated cells showed increased (2-fold) glycerol incorporation into triacylglycerol. These results demonstrate that PAF enhances rapid accumulation of diacyl-PtdOH mass, and that increased de novo synthesis may contribute to PtdOH mass accumulation.
Tou
J
J
Department of Biochemistry, Tulane University School of Medicine, New Orleans, LA 70112.
Jeter
J R
JR
Dola
C P
CP
Venkatesh
S
S
D019852:Diacylglycerol Kinase; D004075:Diglycerides / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005989:Glycerides / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism; D006801:Humans; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D010712:Phosphatidic Acids / Q000378:metabolism*; D010770:Phosphotransferases / Q000378:metabolism; D010972:Platelet Activating Factor / Q000494:pharmacology*
D004075:Diglycerides; D005989:Glycerides; D010712:Phosphatidic Acids; D010972:Platelet Activating Factor; D010770:Phosphotransferases; D019852:Diacylglycerol Kinase; D005990:Glycerol