Purdon A D, Smith J B
J Biol Chem. 1985 Oct 15;260(23):12700-4.
In this work, the uptake and release of [3H]arachidonic acid by the diacyl and ether species of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) in human platelets were studied. Uptake of [3H]arachidonic acid into 1,2-diacyl-PC and 1,2-diacyl-PE was much greater than into the ether phospholipids of the same class. In [3H]arachidonoyl-labeled platelets stimulated by thrombin, there was a decrease in total [3H] arachidonoyl-PC. This was accounted for mostly by a decrease in 1-acyl-2-[3H]arachidonoyl-PC while the level of 1-O-alkyl-2-[3H]arachidonoyl-PC (a precursor for platelet-activating factor) increased slightly. However, in ionophore A23187-stimulated platelets, the reduction of total [3H]arachidonoyl-PC was due to a decrease in both 1-acyl-2-[3H]arachidonoyl-PC and 1-O-alkyl-2-[3H] arachidonoyl-PC, suggesting that ionophore should yield more platelet-activating factor than thrombin. In both thrombin- and ionophore-stimulated platelets, there was a net increase in total [3H]arachidonoyl-PE. This consisted of a decrease in 1,2-diacyl-PE, which was essentially complete by 1 min, followed by an increase in 1-O-alk-1'-enyl-2-[3H]arachidonoyl-PE, which was slower and not apparent until 3-5 min after thrombin. During reincubation of labeled platelets with saline, the 1-O-alkyl-2-[3H]arachidonoyl-PC increased by a factor of 2, between 0 and 4 h, with no significant change in the radioactivity of any other phospholipid. Thus, upon stimulation of human platelets, arachidonic is released from both 1,2-diacyl-PC and 1,2-diacyl-PE for metabolism by platelet cyclooxygenase and lipoxygenase, while certain ether pools of PC and PE also collect arachidonic acid.
在本研究中，对人血小板中磷脂酰胆碱（PC）和磷脂酰乙醇胺（PE）的二酰基和醚类物质摄取及释放[3H]花生四烯酸的情况进行了研究。[3H]花生四烯酸进入1,2 - 二酰基 - PC和1,2 - 二酰基 - PE的量远大于进入同类醚磷脂的量。在凝血酶刺激的[3H]花生四烯酰标记血小板中，总[3H]花生四烯酰 - PC减少。这主要是由于1 - 酰基 - 2 - [3H]花生四烯酰 - PC减少，而1 - O - 烷基 - 2 - [3H]花生四烯酰 - PC（血小板活化因子的前体）水平略有增加。然而，在离子载体A23187刺激的血小板中，总[3H]花生四烯酰 - PC的减少是由于1 - 酰基 - 2 - [3H]花生四烯酰 - PC和1 - O - 烷基 - 2 - [3H]花生四烯酰 - PC均减少，这表明离子载体产生的血小板活化因子应比凝血酶更多。在凝血酶和离子载体刺激的血小板中，总[3H]花生四烯酰 - PE均有净增加。这包括1,2 - 二酰基 - PE减少，在1分钟时基本完成，随后1 - O - 烯基 - 2 - [3H]花生四烯酰 - PE增加，凝血酶作用后3 - 5分钟时增加较慢且不明显。在用盐水对标记血小板进行再孵育期间，0至4小时内1 - O - 烷基 - 2 - [3H]花生四烯酰 - PC增加了2倍，其他任何磷脂的放射性均无显著变化。因此，在刺激人血小板时，花生四烯酸从1,2 - 二酰基 - PC和1,2 - 二酰基 - PE中释放出来，由血小板环氧化酶和脂氧合酶进行代谢，而PC和PE的某些醚类池也会收集花生四烯酸。
