Chilton F H, Ellis J M, Olson S C, Wykle R L
J Biol Chem. 1984 Oct 10;259(19):12014-9.
1-O-[3H]Alkyl-2-lyso-sn-glycero-3-phosphocholine (1-O-[3H]alkyl-2-lyso-GPC) incubated with human polymorphonuclear leukocytes (PMN) for 30 min is metabolized to 1-O-alkyl-2-acyl-GPC containing greater than 80% arachidonate at the 2 position (Chilton, F. H., O'Flaherty, J. T., Ellis, J. M., Swendsen, C. L., and Wykle, R. L. (1983) J. Biol. Chem. 258, 7268-7271). PMN containing 1-O-[3H]alkyl-2-arachidonoyl-GPC incorporated into their cellular phospholipids in this manner were stimulated with Ca2+ ionophore (A23187). Within 5 min after stimulation, 14%, 7%, and 7% of the total 1-O-[3H]alkyl-2-arachidonoyl-GPC in the cells had been converted to 1-O-[3H]alkyl-2-acetyl-GPC (platelet-activating factor), 1-O-[3H]alkyl-2-lyso-GPC, and 3H-labeled neutral lipid, respectively. Stimulation by opsonized zymosan yielded similar results. In related studies, cells were labeled with 1-O-hexadecyl-2-arachidonoyl-GPC containing a [methyl-14C] choline moiety. The nature of the long-chain acyl residues in the sn-2 position of the labeled 1-O-hexadecyl-2-acyl-GPC remaining after stimulation with A23187 was examined. Analysis by high-performance liquid chromatography using synthetic 1-O-hexadecyl-2-acyl-GPC standards indicated there is a time-dependent loss of arachidonate from the 2 position of the labeled 1-O-hexadecyl-2-arachidonoyl-GPC followed by reacylation by other fatty acids (primarily linoleic and oleic). This shift in the acylation pattern exhibited after Ca2+ ionophore stimulation was further examined in PMN preincubated with A23187 and subsequently incubated with labeled 1-O-alkyl-2-lyso-GPC; the stimulated cells produced 1-O-[3H]alkyl-2-acetyl-GPC (greater than 15% of total label) and 1-O-[3H]alkyl-2-acyl-GPC containing linoleic acid and oleic acid, rather than arachidonic acid in the sn-2 position. The findings demonstrate that upon stimulation of PMN, 1-O-alkyl-2-arachidonoyl-GPC can yield arachidonate and 1-O-alkyl-2-lyso-GPC; the 1-O-alkyl-2-lyso-GPC formed may be acetylated producing platelet-activating factor or reacylated with fatty acyl residues other than arachidonate.
1-O-[³H]烷基-2-溶血-sn-甘油-3-磷酸胆碱（1-O-[³H]烷基-2-溶血-GPC）与人多形核白细胞（PMN）孵育30分钟后，会代谢生成在2位含有大于80%花生四烯酸的1-O-烷基-2-酰基-GPC（奇尔顿，F. H.，奥弗莱厄蒂，J. T.，埃利斯，J. M.，斯文森，C. L.，和怀克尔，R. L.（1983年）《生物化学杂志》258，7268 - 7271）。以这种方式将1-O-[³H]烷基-2-花生四烯酰基-GPC掺入细胞磷脂中的PMN，用钙离子载体（A23187）刺激。刺激后5分钟内，细胞中总的1-O-[³H]烷基-2-花生四烯酰基-GPC分别有14%、7%和7%转化为1-O-[³H]烷基-2-乙酰基-GPC（血小板活化因子）、1-O-[³H]烷基-2-溶血-GPC和³H标记的中性脂质。经调理酵母聚糖刺激也得到了类似结果。在相关研究中，细胞用含有[甲基-¹⁴C]胆碱部分的1-O-十六烷基-2-花生四烯酰基-GPC进行标记。研究了用A23187刺激后剩余的标记1-O-十六烷基-2-酰基-GPC的sn-2位长链酰基残基的性质。使用合成1-O-十六烷基-2-酰基-GPC标准品通过高效液相色谱分析表明，标记的1-O-十六烷基-2-花生四烯酰基-GPC的2位花生四烯酸存在时间依赖性损失，随后被其他脂肪酸（主要是亚油酸和油酸）再酰化。在预先用A23187孵育然后与标记的1-O-烷基-2-溶血-GPC孵育的PMN中，进一步研究了钙离子载体刺激后酰化模式的这种变化；受刺激的细胞产生了1-O-[³H]烷基-2-乙酰基-GPC（占总标记的大于15%）和在sn-2位含有亚油酸和油酸而非花生四烯酸的1-O-[³H]烷基-2-酰基-GPC。这些发现表明，在刺激PMN时，1-O-烷基-2-花生四烯酰基-GPC可产生花生四烯酸和1-O-烷基-2-溶血-GPC；形成的1-O-烷基-2-溶血-GPC可能被乙酰化生成血小板活化因子，或被除花生四烯酸以外的脂肪酰基残基再酰化。
