INDUCTION OF MATURATION IN CUMULUS CELL-ENCLOSED MOUSE OOCYTES BY FOLLICLE-STIMULATING-HORMONE AND EPIDERMAL GROWTH-FACTOR - EVIDENCE FOR A POSITIVE STIMULUS OF SOMATIC-CELL ORIGIN
INDUCTION OF MATURATION IN CUMULUS CELL-ENCLOSED MOUSE OOCYTES BY FOLLICLE-STIMULATING-HORMONE AND EPIDERMAL GROWTH-FACTOR - EVIDENCE FOR A POSITIVE STIMULUS OF SOMATIC-CELL ORIGIN
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DOI：
10.1002/jez.1402450113
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发表时间：
1988-01-01
影响因子：
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通讯作者：
EPPIG, JJ
中科院分区：
文献类型：
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作者：
DOWNS, SM;DANIEL, SAJ;EPPIG, JJ
在体外用嘌呤、二丁酰环磷酸腺苷（dbcAMP）或磷酸二酯酶抑制剂3-异丁基-1-甲基黄嘌呤（IBMX）维持小鼠卵母细胞减数分裂阻滞时，研究了卵泡刺激素（FSH）、表皮生长因子（EGF）和二丁酰环磷酸鸟苷（dbcGMP）作为卵丘细胞封闭的小鼠卵母细胞生发泡破裂（GVBD）诱导剂的功效。当FSH加入到含次黄嘌呤（HX）的培养基中时，对卵母细胞成熟的影响首先是抑制性的，然后是刺激性的。EGF在所有测试时间点刺激GVBD。FSH和EGF也诱导GVBD时，卵母细胞被逮捕与dbcAMP，IBMX，或鸟苷。二丁酰cGMP刺激GVBD时，减数分裂阻滞与HX维持，但不是当卵母细胞减数分裂阻滞与鸟苷，并抑制在dbcAMP补充培养基。FSH和dbcGMP在对照培养基中产生了卵母细胞成熟的短暂延迟，但FSH的作用更为明显。EGF对成熟动力学没有影响。FSH和EGF的作用需要卵丘细胞的存在。这两种药物均显着刺激卵母细胞-卵丘细胞复合体中cAMP的产生。复合物的短暂暴露于高浓度的dbcAMP诱导GVBD，表明FSH和EGF可能通过cAMP依赖性过程起作用。在卵丘细胞包裹的卵母细胞中，FSH和EGF诱导的GVBD频率显着高于在去除卵丘细胞的情况下培养的卵母细胞的GVBD频率。 因此，成熟的诱导显然不仅仅是通过卵母细胞-卵丘细胞解偶联和终止从卵丘细胞到卵母细胞的抑制性减数分裂信号的转移来介导的。这些数据表明，在卵丘细胞内产生一个积极的信号，以响应激素治疗，作用于卵母细胞，刺激GVBD在持续存在的抑制因子。
The efficacy of follicle-stimulating hormone (FSH), epidermal growth factor (EGF), and dibutyryl cGMP (dbcGMP) as inducers of germinal vesicle breakdown (GVBD) in cumulus cell-enclosed mouse oocytes were examined when meiotic arrest was maintained in vitro with purines, dibutyryl cAMP (dbcAMP), or the phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine (IBMX). When FSH was added to hypoxanthine (HX)-containing medium, the effect on oocyte maturation was at first inhibitory and later stimulatory. EGF stimulated GVBD at all time points tested. FSH and EGF also induced GVBD when oocytes were arrested with dbcAMP, IBMX, or guanosine. Dibutyryl cGMP stimulated GVBD when meiotic arrest was maintained with HX, but not when oocytes were meiotically arrested with guanosine, and was inhibitory in dbcAMP-supplemented medium. FSH and dbcGMP produced a transient delay of oocyte maturation in control medium, but the FSH effect was much more pronounced. EGF had no effect on maturation kinetics. The actions of FSH and EGF required the presence of cumulus cells. Both agents significantly stimulated cAMP production in oocyte-cumulus cell complexes. A brief exposure of complexes to a high concentration of dbcAMP induced GVBD, suggesting that FSH and EGF may act via a cAMP-dependent process. The frequency of FSH- and EGF-induced GVBD in cumulus cell-enclosed oocytes was significantly higher than the frequency of GVBD when oocytes were cultured while denuded of cumulus cells. Thus, the induction of maturation is apparently not mediated solely by oocyte-cumulus cell uncoupling and termination of the transfer of an inhibitory meiotic signal from cumulus cells to the oocyte. The data suggest the generation of a positive signal within cumulus cells in response to hormone treatment that acts upon the oocyte to stimulate GVBD in the continued presence of inhibitory factors.