FSH-INDUCED EXPANSION OF THE MOUSE CUMULUS-OOPHORUS INVITRO IS DEPENDENT UPON A SPECIFIC FACTOR(S) SECRETED BY THE OOCYTE
FSH-INDUCED EXPANSION OF THE MOUSE CUMULUS-OOPHORUS INVITRO IS DEPENDENT UPON A SPECIFIC FACTOR(S) SECRETED BY THE OOCYTE
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DOI：
10.1016/0012-1606(90)90172-f
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发表时间：
1990-03-01
影响因子：
2.7
通讯作者：
EPPIG, JJ
中科院分区：
文献类型：
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作者：
BUCCIONE, R;VANDERHYDEN, BC;EPPIG, JJ
尽管已表明颗粒细胞调节哺乳动物卵母细胞的生长和减数分裂成熟，但几乎没有证据表明卵母细胞在颗粒细胞的分化或功能中起作用。为了验证卵母细胞参与调节颗粒细胞功能这一假设，通过显微外科手术从分离的卵母细胞 - 卵丘细胞复合体中去除卵母细胞，并检测无卵母细胞复合体对促卵泡激素（FSH）刺激发生扩展的能力。FSH提高了完整复合体中细胞内cAMP水平、透明质酸合成酶系统的活性，并诱导卵丘扩展。相比之下，FSH不会诱导无卵母细胞复合体中透明质酸合成酶活性增加或卵丘扩展。因此，卵母细胞的参与对于卵丘细胞在体外响应FSH刺激合成透明质酸并发生卵丘扩展是必要的。FSH在完整复合体和无卵母细胞复合体中诱导细胞内cAMP升高的程度相同，且cAMP类似物8 - 溴环腺苷酸（8Br - cAMP）不会刺激无卵母细胞复合体扩展。因此，卵母细胞对卵丘的影响发生在卵丘细胞中cAMP水平升高的下游。表皮生长因子（EGF）是完整复合体中卵丘扩展的一种强效刺激剂，其作用机制可能至少在最初与FSH不同，在去除卵母细胞后不能刺激卵丘扩展。接下来，将无卵母细胞复合体与生发泡期的去核卵母细胞共培养，或在由去核卵母细胞调节的培养基中培养。在这两种情况下，FSH或EGF都能刺激无卵母细胞复合体扩展。扩展程度与用于调节培养基的卵母细胞数量直接相关。卵母细胞与卵丘细胞之间的接触对于卵丘扩展不是必需的。相反，卵母细胞分泌的一种（或多种）因子对于卵丘细胞响应FSH或EGF发生扩展是必要的。FSH不会诱导无卵母细胞复合体在由各种体细胞（如颗粒细胞、成纤维细胞和支持细胞）、混合的雄性生殖细胞群或精子调节的培养基中扩展。这表明这种使能扩展的活性是卵母细胞所特有的。这些结果表明卵母细胞参与调节卵丘细胞的功能。
Although it has been shown that granulosa cells regulate the growth and meiotic maturation of mammalian oocytes, there is little evidence of a role for the oocyte in the differentiation or function of granulosa cells. To test the hypothesis that the oocyte participates in the regulation of granulosa cell function, oocytes were removed from isolated oocyte-cumulus cell complexes by a microsurgical procedure and oocytectomized complexes were tested for their ability to undergo expansion in response to follicle-stimulating hormone (FSH). FSH increased the levels of intracellular cAMP, the activity of the hyaluronic acid-synthesizing enzyme system, and induced cumulus expansion in intact complexes. In contrast, FSH did not induce increased hyaluronic acid-synthesizing enzyme activity or cumulus expansion in oocytectomized complexes. Therefore, the participation of the oocyte is necessary for the cumulus cells to synthesize hyaluronic acid and undergo cumulus expansion in vitro in response to stimulation with FSH. FSH induced the elevaton of intracellular cAMP to the same extent in both intact and oocytectomized complexes and the cAMP analog 8-bromo cyclic adenosine monophosphate (8Br-cAMP) did not stimulate expansion in oocytectomized complexes. Therefore, the influence of the oocyte on cumulus occurs downstream from the elevation of cAMP levels in the cumulus cells. Epidermal growth factor (EGF), a potent stimulator of cumulus expansion in intact complexes, which probably acts by a mechanism at least initially different from FSH, failed to stimulate cumulus expansion after oocytectomy. Next, oocytectomized complexes were either cocultured with germinal vesicle stage denuded oocytes or cultured in medium conditioned by denuded oocytes. In both cases, FSH or EGF stimulated expansion by oocytectomized complexes. The degree of expansion was directly correlated to the number of oocytes used to condition the medium. Contact between the oocyte and the cumulus cells is not necessary for cumulus expansion. Rather, a factor(s) secreted by the oocyte is necessary for the cumulus cells to undergo expansion in response to either FSH or EGF. FSH did not induce expansion of oocytectomized complexes in media conditioned by various somatic cells such as granulosa cells, fibroblasts, and Sertoli cells; by a mixed population of male germ cells; or by spermatozoa. This suggest that the expansion enabling activity is specific to the oocyte. These results demonstrate that the oocyte participates in the regulation of cumulus cell function.