螯合细胞外钙离子对体外培养的大鼠卵巢颗粒细胞成熟的影响

Effect of Chelation of Extracellular Calcium on Maturation of Cultured Rat Granulosa Cells

在发现利用钙离子螯合剂EGTA螯合细胞外钙离子(Ca2+)后,可以显著抑制促滤泡(激)素(FSH)刺激体外培养的颗粒细胞合成和分泌雌激素,并且该抑制作用呈剂量依赖性。假设该特异性反应是通过Ca2+影响细胞内腺苷酸环化酶(AC)发挥作用的,因为Ca2+具有激活ACVIII的作用。通过RT-PCR和Northern印迹检测大鼠不同阶段卵巢组织中ACVIII的表达。结果表明,虽然Ca2+可以调控颗粒细胞类固醇激素的合成,但不同阶段的卵巢组织中均检测不到ACVIII的mRNA。实验间接提示了Ca2+促进颗粒细胞成熟的作用不是通过ACVIII发挥作用的,而可能是通过其他AC同工酶或其他Ca2+信号通路发挥作用。

Calcium is an important cellular signal. The aim of the present study is to examine the effect of chelation of extracellular calcium on the maturation of cultured rat granulosa cells. The results demonstrate that addition of EGTA, a chelator of extracellular calcium, significantly inhibits the estradiol production in cultured rat granulosa cells stimulated by FSH in a dose-dependent manner. As it is known that adenylyl cyclase VIII can be promoted by intercellular calcium, we hypothesize that the action of calcium may be through activating adenylyl cyclase VIII in rat granulosa cells. However, the results of our RT-PCR and Northern blot indicate that the role of calcium is not via adenylyl cyclase VIII isoform but may be through other pathways in cultured rat granulosa cells.