Extracellular Signal-Regulated Kinase (ERK) Activation and Mitogen-Activated Protein Kinase Phosphatase 1 Induction by Pulsatile Gonadotropin-Releasing Hormone in Pituitary Gonadotrophs.
Extracellular Signal-Regulated Kinase (ERK) Activation and Mitogen-Activated Protein Kinase Phosphatase 1 Induction by Pulsatile Gonadotropin-Releasing Hormone in Pituitary Gonadotrophs.
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DOI：
10.1155/2012/198527
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Miyazaki K
中科院分区：
文献类型：
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作者：
Kanasaki H;Purwana I;Oride A;Mijiddorj T;Miyazaki K
下丘脑分泌促性腺激素释放激素脉冲的频率不同，对促性腺激素亚单位基因黄体生成素β(β)和卵泡刺激素β(β)的表达有不同的调节作用。促性腺激素释放激素β在较慢的脉冲频率下优先刺激，而促黄体生成素β在较快的脉冲频率下优先刺激。有几个信号通路被激活，包括丝裂原激活的蛋白激酶(MAPK)、蛋白激酶C、钙内流和钙-钙调蛋白激酶，这些信号通路在特定条件下可能受到优先调节。以往的研究表明，在促性腺激素释放激素(GnRH)诱导促性腺激素亚单位基因表达的过程中，MAPK途径，尤其是细胞外信号调节激酶(ERK)起着至关重要的作用，而MAPK磷酸酶(MKPs)则通过苏氨酸和/或酪氨酸残基的去磷酸化来灭活MAPK。GnRH也可以诱导MKPs，GnRH信号通路中MAPK信号和MKPs之间的潜在反馈调节在促性腺激素细胞中是明显的。本文就不同频率的GnRH刺激对ERK的激活模式和MKP的诱导进行了综述和观察。
The frequency of gonadotropin-releasing hormone (GnRH) pulse secreted from the hypothalamus differently regulates the expressions of gonadotropin subunit genes, luteinizing hormone β (LHβ) and follicle-stimulating hormone β (FSHβ), in the pituitary gonadotrophs. FSHβ is preferentially stimulated at slower GnRH pulse frequencies, whereas LHβ is preferentially stimulated at more rapid pulse frequencies. Several signaling pathways are activated, including mitogen-activated protein kinase (MAPK), protein kinase C, calcium influx, and calcium-calmodulin kinases, and these may be preferentially regulated under certain conditions. Previous studies demonstrated that MAPK pathways, especially the extracellular signal-regulated kinase (ERK), play an essential role for induction of gonadotropin subunit gene expression by GnRH, whereas, MAPK phosphatases (MKPs) inactivate MAPKs through dephosphorylation of threonine and/or tyrosine residues. MKPs are also induced by GnRH, and potential feedback regulation between MAPK signaling and MKPs within the GnRH signaling pathway is evident in gonadotrophs. In this paper, we reviewed and mainly focused on our observations of the pattern of ERK activation and the induction of MKP by different frequencies of GnRH stimulation.