p38MAPK信号通路选择性调节FSH对甾体生成 的诱导作用研究

利用乙烯雌酚(DES)处理23日龄SD大鼠,分离卵巢颗粒细胞(GC)进行无血清培养。结果表明,FSH(50ng/m1)处理GC,可迅速激活有丝分裂原蛋白激酶(p38MAPK),FSH处理5min便可观察到磷酸化的p38MAPK;FSH处理30min,磷酸化的p38MAPK水平达到最高;向培养液中加入H89(蛋白激酶A抑制剂,10μM),则显著抑制了FSH对p38MAPK的激活作用,提示这种激活作用依赖于蛋白激酶A(PKA)。用SB203580(p38MAPK抑制剂,20μM)抑制p38MAPK激活,则进一步提高了FSH对孕酮和甾体生成快速调节蛋白(StAR)的诱导作用,同时降低了FSH对雌激素生成的促进作用(p<0.01)。RT-PCR结果显示:抑制p38MAPK活性后,FSH对StARmRNA刺激作用明显增强,但对细胞色素P450芳香化酶(P450arom)mRNA的诱导作用却减弱了(p<0.05)。激光共聚焦和蛋白印迹结果显示:在GC中,StAR蛋白主要分布在线粒体中;与对照组相比,FSH显著提高了StAR的荧光强度和蛋白水平;抑制p38MAPK活性则增强了FSH对StAR蛋白表达的诱导作用。

Study on FSH-activated p38MAPK Pathway Differently Regulated the Progesterone and Estrogen Synthesis in the Cultured Primary GCs

GCs were obtained from the ovaries of activity of DES-treated immature rats and cultured in serum-free medium. FSH receptor occupancy lesded to phosphorylation/activation of p38 MAPK in time-dependent manner. Phosphorylated p38 MAPK by FSH was observed within 5 min and reached the highest level at 30 min. Moreover, such activation was protein kinase A-dependent as indicated by the results using specific inhibitors.Interestingly.inhibition of p38 MAPK acitivity with SB203580 augmented estradiol production at the same time (p<0.01). RT-PCR data showed that inclusion of SB203580 in the FSH-stimulated FSH-induced STAR mRNA Production, while decreased the FSH-stimulated P450arom mRNA expression of STAR in mitochondria than FSH treatment alone.