Nakamura T, Ishigami T, Makino N, Sakamoto K
Institute of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan.
J Biochem. 2001 Jun;129(6):937-42. doi: 10.1093/oxfordjournals.jbchem.a002940.
Prostaglandin (PG) F(2)a is known to initiate luteal cell apoptosis in the bovine corpus luteum (CL) via its specific receptor (FP) on the luteal membrane by inducing intracellular Ca(2+) mobilization and the activation of PKC. In order to identify the signaling components involved in cell apoptosis, mRNA levels and activities of antioxidative enzymes were analyzed using bovine CL at different stages of the estrous cycle. Northern blot analysis revealed that the levels of two isozymes of superoxide dismutase (SOD), the Mn and Cu/Zn types, and catalase are highly enriched in the middle estrous phase, whereas glutathione peroxidase (GPx) levels gradually decrease as the estrous cycle progresses. The incubation of bovine luteal cells with H(2)O(2) and mercaptosuccinate (MS), a specific inhibitor of GPx, resulted in an increase in chromatin DNA condensation and apoptotic DNA fragmentation. Analyses of the enzymatic activities of GPx and catalase support the RNA data, indicating that H(2)O(2) produced due to the lack of GPx is a potent inducer of luteal cell apoptosis.
已知前列腺素（PG）F(2)α通过诱导细胞内Ca(2+)动员和蛋白激酶C（PKC）的激活，经由黄体细胞膜上的特异性受体（FP）引发牛黄体（CL）中的黄体细胞凋亡。为了确定参与细胞凋亡的信号成分，利用处于发情周期不同阶段的牛黄体分析了抗氧化酶的mRNA水平和活性。Northern印迹分析显示，超氧化物歧化酶（SOD）的两种同工酶（锰型和铜/锌型）以及过氧化氢酶的水平在发情中期高度富集，而随着发情周期的进展，谷胱甘肽过氧化物酶（GPx）水平逐渐降低。用H(2)O(2)和GPx的特异性抑制剂巯基琥珀酸（MS）孵育牛黄体细胞，导致染色质DNA凝聚和凋亡性DNA片段化增加。对GPx和过氧化氢酶的酶活性分析支持了RNA数据，表明由于缺乏GPx而产生的H(2)O(2)是黄体细胞凋亡的有效诱导剂。
