CYLOOXYGENASE-DEPENDENT FORMATION OF THE ISOPROSTANE, 8-EPI PROSTAGLANDIN FA(2-ALPHA)
CYLOOXYGENASE-DEPENDENT FORMATION OF THE ISOPROSTANE, 8-EPI PROSTAGLANDIN FA(2-ALPHA)
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DOI：
10.1074/jbc.270.17.9800
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发表时间：
1995-04-28
影响因子：
4.8
通讯作者：
FITZGERALD, GA
中科院分区：
文献类型：
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作者：
PRATICO, D;LAWSON, JA;FITZGERALD, GA
异前列腺素是前列腺素 (PG) 异构体家族，以不依赖酶的方式形成。它们在血浆中循环并通过尿液排出。其中之一，8-epi PGF(2α) 是一种血管收缩剂和促细胞分裂剂，其作用可被血栓素拮抗剂阻止。假定 8-epi PGF(2α) 可以通过环加氧酶 (COX) 形成 (Corey, E. J.、Shih, C.、Shig, N-Y. 和 Shimoji, K. (1984) Tetrahedron Letts. 44, 5013-5016 ；Hecker, M.、Ullrich, V.、Fischer, C. 和 Meese, C. O. (1987)fur J. Biochem. 169, 113-123)，并且这可能会混淆它作为自由基生成指标的用途，我们试图描述人类血小板形成它的机制。胶原蛋白、凝血酶和花生四烯酸的阈值浓度激活血小板导致 8-epi PGF(2 α) 的形成，与 COX 产物、血栓素和 12 的形成一致。脂氧合酶产物，12-羟基二十碳四烯酸，使用气相色谱-质谱法通过选择离子监测测定法检测。该作用似乎对 F-2 异前列烷中的 8 epi PGF(2α) 具有选择性。用阿司匹林或吲哚美辛预处理血小板可消除 8-epi PGF(2α) 的形成。高剂量胶原蛋白或凝血酶、佛波酯、佛波醇 12-肉豆蔻酸酯 IS-乙酸酯或前列腺素内过氧化物类似物 U 46619 对血小板的 COX 依赖性激活与 8-epi PGF(2 α) 的形成无关。血小板 COX 形成的材料性质作为 8-epi PGF(2 α) 的确认包括其超过三个高分辨率的共色谱法高效液相色谱系统，电子轰击质谱鉴定，以及部分纯化的COX的形成。血小板血栓素形成的抑制与 8-epi PGF(2α) 形成的增强有关。健康志愿者在血清中形成的 8 epi PGF(2 α) 的主要成分被证明对体内阿司匹林的抑制敏感。除了通过自由基催化机制产生外，8 epi PGF(2 α) 还可能由人血小板形成为 PG。鉴于血小板 COX 的激活是许多人类综合症的特征，这些综合症被认为与自由基的产生有关，因此对该途径的贡献的评估与使用 8 epi PGF(2 α) 作为体内脂质过氧化的指标有关。
Isoprostanes are a family of prostaglandin (PG) isomers formed in an enzyme-independent manner. They circulate in plasma and are excreted in urine. One of them, 8-epi PGF(2 alpha) is a vasoconstrictor and mitogen, effects which are prevented by thromboxane antagonists. Given that 8-epi PGF(2 alpha) may be formed by cyclooxygenase (COX) (Corey, E. J., Shih, C., Shig, N-Y., and Shimoji, K. (1984) Tetrahedron Letts. 44, 5013-5016; Hecker, M., Ullrich, V., Fischer, C., and Meese, C. O. (1987) fur J. Biochem. 169, 113-123) and that this might confound its use as an index of free radical generation, we sought to characterize the mechanism of its formation by human platelets.Activation of platelets by threshold concentrations of collagen, thrombin, and arachidonic acid resulted in formation of 8-epi PGF(2 alpha) coincident with that of the COX product, thromboxane, and the 12 lipoxygenase product, 12-hydroxyeicosatetraenoic acid, as detected by selected ion monitoring assays using gas chromatography-mass spectrometry. The effect appeared selective for 8 epi PGF(2 alpha) among the F-2 isoprostanes. Pretreatment of platelets with aspirin or indomethacin abolished 8-epi PGF(2 alpha) formation. COX-independent activation of platelets by high doses of collagen or thrombin, by the phorbol ester, phorbol 12-myristate IS-acetate, or the prostaglandin endoperoxide analog U 46619 was not associated with 8-epi PGF(2 alpha) formation.Confirmation of the nature of the material formed by platelet COX as 8-epi PGF(2 alpha) included its cochromatography over three highly resolving high performance liquid chromatography systems, identification by electron impact mass spectrometry, and its formation by partially purified COX. Inhibition of platelet thromboxane formation was associated with augmented 8-epi PGF(2 alpha) formation. A major component of 8 epi PGF(2 alpha) formed in serum by healthy volunteers was shown to be sensitive to inhibition by aspirin err vivo.In addition to its generation by free radical catalyzed mechanisms, 8 epi PGF(2 alpha) may be formed as a PG by human platelets. Given that activation of platelet COX characterizes many of the human syndromes which are putatively associated with free radical generation, assessment of the contribution of this pathway is relevant to the use of 8 epi PGF(2 alpha) as an index of lipid peroxidation in vivo.