Wu X M, Sawada M, Carlson J C
Biology Department, University of Waterloo, Ontario, Canada.
Biol Reprod. 1992 Dec;47(6):1053-8. doi: 10.1095/biolreprod47.6.1053.
The ability of the superoxide radical (SOR) generated by xanthine oxidase to activate phospholipase A2 (PLA2) was examined in microsomes prepared from luteinized rat ovaries. Treatment of microsomes with xanthine oxidase resulted in a rapid burst in SOR formation followed by an increase in PLA2 activity. Stimulation of PLA2 activity was dose related and similar in microsomes prepared from control or prostaglandin F2 alpha (PGF2 alpha)-treated rats. Activation was inhibited by the antioxidants, vitamin E and nordihydroguaiaretic acid, and by superoxide dismutase and catalase, which metabolize SOR and H2O2 to remove reactive oxygen species from the cell. The stimulation of PLA2 activity by xanthine oxidase was dependent upon the addition of calcium ions, and it was highest in samples in which cytosol was added to membranes. These results indicate that the SOR and/or H2O2 may mediate PLA2 activation, which may be involved in the luteolytic process.
在从黄体化大鼠卵巢制备的微粒体中，检测了黄嘌呤氧化酶产生的超氧阴离子自由基（SOR）激活磷脂酶A2（PLA2）的能力。用黄嘌呤氧化酶处理微粒体导致SOR形成迅速爆发，随后PLA2活性增加。PLA2活性的刺激与剂量相关，并且在从对照或前列腺素F2α（PGF2α）处理的大鼠制备的微粒体中相似。抗氧化剂维生素E和去甲二氢愈创木酸、超氧化物歧化酶和过氧化氢酶可抑制激活，它们可代谢SOR和H2O2以从细胞中去除活性氧。黄嘌呤氧化酶对PLA2活性的刺激依赖于钙离子的添加，并且在向膜中添加胞质溶胶的样品中最高。这些结果表明，SOR和/或H2O2可能介导PLA2激活，这可能参与黄体溶解过程。
