The mechanism of cumulus cell-oocyte uncoupling: evidence for the participation of both cumulus cells and oocytes.
The mechanism of cumulus cell-oocyte uncoupling: evidence for the participation of both cumulus cells and oocytes.
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卵丘细胞-卵母细胞解偶联的机制：卵丘细胞和卵母细胞共同参与的证据。
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发表时间：
1982
期刊：
影响因子：
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通讯作者：
P. Ward
中科院分区：
文献类型：
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作者：
J. Eppig;P. Ward
卵丘细胞通过异源缝隙连接与卵母细胞代谢偶联。这种偶联在接近排卵时终止，这种终止似乎与紧邻卵母细胞的卵丘细胞的粘液化有关。本项目的第一个目的是确定促卵泡激素（FSH）诱导卵丘细胞-卵母细胞解偶联是否可以独立于FSH刺激的卵丘粘液化（扩张）而发生。细胞间偶联测量为掺入卵母细胞的放射性标记胆碱（或其代谢物）相对于掺入整个卵丘细胞-卵母细胞复合物的放射性标记总量的百分比。发现用硫酸软骨素B完全抑制FSH刺激的卵丘扩张对FSH刺激的卵丘细胞-卵母细胞解偶联没有抑制作用。这一发现表明，FSH刺激的卵丘扩张是不需要卵丘细胞卵母细胞解偶联。由于17β-雌二醇、睾酮或孕酮不能诱导最大的卵丘细胞解偶联，因此可以得出结论，FSH的解偶联促进作用可能不是由类固醇激素介导的。
当卵母细胞在没有FSH的情况下自发成熟时，发现卵丘细胞和卵母细胞部分解偶联。这种部分解偶联被阻止卵丘细胞卵母细胞复合物的浓度的二丁酰环磷酸腺苷（dbcAMP）或3-异丁基-1-甲基黄嘌呤（IBMX）（分别为0.25和0.10 mM），抑制自发卵母细胞成熟，而不诱导卵丘扩张的孵育。这些抑制剂还阻止了由FSH或促黄体生成素（LH）的生物级制剂引起的解偶联的最大诱导。得出的结论是，需要两个因素带来最大的卵丘细胞-卵母细胞解偶联：一个因素是依赖于促性腺激素对卵丘细胞功能的作用，另一个因素似乎是一个功能的卵母细胞，因为最大的解偶联只能发生后，生发囊泡已经打破。
Cumulus cells are metabolically coupled to oocytes via heterologous gap junctions. This coupling terminates near the time of ovulation, and the termination appears to be correlated with the mucification of the cumulus cells lying immediately adjacent to the oocytes. The first objective of this project was to determine whether follicle stimulating hormone (FSH) induction of cumulus cell-oocyte uncoupling could occur independently of FSH-stimulated cumulus mucification (expansion). Intercellular coupling was measured as a percentage of radiolabeled choline (or its metabolites) that was incorporated into the oocyte relative to the total amount of radiolabel incorporated into the entire cumulus cell-oocyte complex. It was found that the complete suppression of FSH-stimulated cumulus expansion with chondroitin sulfate B had no suppressive effect on FSH-stimulated cumulus cell-oocyte uncoupling. This finding showed that FSH-stimulated cumulus expansion was not required for cumulus cell-oocyte uncoupling. Since 17β-estradiol, testosterone, or progesterone could not induce maximal cumulus cell uncoupling, it was concluded that the uncoupling-promoting action of FSH was probably not mediated by steroid hormones.
A partial uncoupling of cumulus cells and oocytes was found when spontaneous oocyte maturation had occurred in the absence of FSH. This partial uncoupling was prevented by incubation of cumulus cell-oocyte complexes in concentrations of dibutyryl cyclic adenosine monophosphate (dbcAMP) or 3-isobutyl-1-methyl xanthine (IBMX) (0.25 and 0.10 mM respectively) that suppressed spontaneous oocyte maturation without inducing cumulus expansion. These inhibitors also prevented the maximal induction of uncoupling that would have been provoked by biological grade preparations of either FSH or luteinizing hormone (LH). It was concluded that two factors were required to bring about maximal cumulus cell-oocyte uncoupling: one factor was dependent upon the action of gonadotropins on cumulus cell function, the other factor appeared to be a function of the oocytes, since maximal uncoupling could occur only after the germinal vesicles had broken down.