Gonadotropin-releasing hormone positively regulates steroidogenesis via extracellular signal-regulated kinase in rat Leydig cells.
Gonadotropin-releasing hormone positively regulates steroidogenesis via extracellular signal-regulated kinase in rat Leydig cells.
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DOI：
10.1038/aja.2010.158
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发表时间：
2011-03
影响因子：
2.9
通讯作者：
B. Yao;Hai-yan Liu;Yu-chun Gu;Sha-shan Shi;Xiao-qian Tao;Xiao-jun Li;Y. Ge;Ying-xia Cui;
中科院分区：
文献类型：
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作者：
B. Yao;Hai-yan Liu;Yu-chun Gu;Sha-shan Shi;Xiao-qian Tao;Xiao-jun Li;Y. Ge;Ying-xia Cui;
促性腺激素释放激素（GnRH）由下丘脑内的神经元分泌，是所有脊椎动物生殖功能所必需的。GnRH也存在于脑外器官中，在睾丸间质细胞类固醇生成中起重要作用。然而，介导这一功能的信号通路在很大程度上仍然未知。在这项研究中，我们研究了丝裂原活化蛋白激酶（MAPK）途径的成分是否参与GnRH激动剂（GnRHa）诱导的大鼠间质细胞睾丸类固醇生成。建立大鼠间质细胞原代培养。采用RT-PCR、Western blot和放射免疫分析法（RIA）检测不同剂量和不同持续时间GnRHa对3β-羟基类固醇脱氢酶（3β-HSD）的表达和睾酮的产生。在MAPK抑制剂PD-98059存在或不存在的情况下，通过Western blot分析GnRHa对ERK1/2、JNK和p38激酶激活的影响。GnRHa诱导睾酮分泌，上调3β-HSD mRNA和蛋白表达；它还能激活ERK1/2，但不能激活JNK和p38激酶。虽然GnRHa在100 nm L−1的浓度下作用最大，但在24 h后，GnRHa对ERK1/2的激活在5 min达到峰值，并在60 min内恢复到基础水平。PD-98059完全阻断ERK1/2的激活、3β-HSD的上调和睾酮的产生。我们的数据显示，在大鼠间质细胞中，GnRH通过ERK信号正向调节类固醇生成。GnRH激活ERK1/2可能是诱导3β-HSD基因表达和酶产生的原因，最终可能调节大鼠间质细胞的甾体生成。
Gonadotropin-releasing hormone (GnRH) is secreted from neurons within the hypothalamus and is necessary for reproductive function in all vertebrates. GnRH is also found in organs outside of the brain and plays an important role in Leydig cell steroidogenesis in the testis. However, the signalling pathways mediating this function remain largely unknown. In this study, we investigated whether components of the mitogen-activated protein kinase (MAPK) pathways are involved in GnRH agonist (GnRHa)-induced testis steroidogenesis in rat Leydig cells. Primary cultures of rat Leydig cells were established. The expression of 3β-hydroxysteroid dehydrogenase (3β-HSD) and the production of testosterone in response to GnRHa were examined at different doses and for different durations by RT-PCR, Western blot analysis and radioimmunoassay (RIA). The effects of GnRHa on ERK1/2, JNK and p38 kinase activation were also investigated in the presence or absence of the MAPK inhibitor PD-98059 by Western blot analysis. GnRHa induced testosterone production and upregulated 3β-HSD expression at both the mRNA and protein levels; it also activated ERK1/2, but not JNK and p38 kinase. Although the maximum effects of GnRHa were observed at a concentration of 100 nmnol L−1 after 24 h, activation of ERK1/2 by GnRHa reached peak at 5 min and it returned to the basal level within 60 min. PD-98059 completely blocked the activation of ERK1/2, the upregulation of 3β-HSD and testosterone production. Our data show that GnRH positively regulates steroidogenesis via ERK signalling in rat Leydig cells. ERK1/2 activation by GnRH may be responsible for the induction of 3β-HSD gene expression and enzyme production, which may ultimately modulate steroidogenesis in rat Leydig cells.