Sahu Kankshi, Gupta Anumegha, Sharma Alka, Tiwari Meenakshi, Pandey Ashutosh N, Prasad Shilpa, Yadav Pramod K, Pandey Ajai K, Shrivastav Tulsidas G, Chaube Shail K
a Cell Physiology Laboratory, Department of Zoology , Institute of Science, Banaras Hindu University , Varanasi , India.
b Department of Kayachikitsa, Faculty of Ayurveda , Banaras Hindu University , Varanasi , India.
Growth Factors. 2018 Apr;36(1-2):41-47. doi: 10.1080/08977194.2018.1475372. Epub 2018 May 29.
In mammals, preovulatory oocytes are encircled by several layers of granulosa cells (GCs) in follicular microenvironment. These follicular oocytes are arrested at diplotene arrest due to high level of cyclic nucleotides from encircling GCs. Pituitary gonadotropin acts at the level of encircling GCs and increases adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5'-cyclic monophosphate (cGMP) and activates mitogen-activated protein kinase 3/1 (MAPK3/1) signaling pathway. The MAPK3/1 disrupts the gap junctions between encircling GCs and oocyte. The disruption of gap junctions interrupts the transfer of cyclic nucleotides to the oocyte that results a drop in intraoocyte cAMP level. A transient decrease in oocyte cAMP level triggers maturation promoting factor (MPF) destabilization. The destabilized MPF finally triggers meiotic resumption from diplotene arrest in follicular oocyte. Thus, MAPK3/1 from GCs origin plays important role in gonadotropin-mediated meiotic resumption from diplotene arrest in follicular oocyte of mammals.
在哺乳动物中，排卵前的卵母细胞在卵泡微环境中被几层颗粒细胞（GCs）所包围。由于周围颗粒细胞产生的高水平环核苷酸，这些卵泡中的卵母细胞停滞在双线期阻滞状态。垂体促性腺激素作用于周围颗粒细胞水平，增加3',5'-环磷酸腺苷（cAMP）和3',5'-环磷酸鸟苷（cGMP），并激活丝裂原活化蛋白激酶3/1（MAPK3/1）信号通路。MAPK3/1破坏了周围颗粒细胞与卵母细胞之间的缝隙连接。缝隙连接的破坏中断了环核苷酸向卵母细胞的传递，导致卵母细胞内cAMP水平下降。卵母细胞cAMP水平的短暂下降会引发成熟促进因子（MPF）的不稳定。不稳定的MPF最终触发卵泡卵母细胞从双线期阻滞状态恢复减数分裂。因此，源自颗粒细胞的MAPK3/1在哺乳动物卵泡卵母细胞中促性腺激素介导的从双线期阻滞恢复减数分裂过程中起重要作用。
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