Gonadotropin-induced delta14-reductase and delta7-reductase gene expression in cumulus cells during meiotic resumption of porcine oocytes.
Gonadotropin-induced delta14-reductase and delta7-reductase gene expression in cumulus cells during meiotic resumption of porcine oocytes.
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发表时间：
2005
期刊：
影响因子：
4.8
通讯作者：
Y. Yamashita;M. Nishibori;T. Terada;N. Isobe;M. Shimada
中科院分区：
文献类型：
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作者：
Y. Yamashita;M. Nishibori;T. Terada;N. Isobe;M. Shimada
黄体酮是在猪卵母细胞减数分裂恢复过程中由卵丘细胞中的胆固醇产生的。在滤泡细胞中，已证明外源性脂蛋白结合胆固醇酯可用于类固醇激素的产生。然而，在无血清培养基中，黄体酮也由 FSH 和 LH 刺激的卵丘卵母细胞复合物分泌，这表明黄体酮可以由卵丘细胞中从头合成的胆固醇产生。在本研究中，我们研究了 Delta14 还原酶和 Delta7 还原酶的表达，它们是将乙酰辅酶 A 转化为胆固醇的超家族成员。通过RT-PCR分析这两个基因的表达。培养至4 h的卵丘细胞中Delta14还原酶mRNA和Delta7还原酶mRNA均低于检测限水平。响应促性腺激素，两种 mRNA 水平均显着上调，并在 20 小时时达到最大值。为了阐明诱导酶在卵丘细胞中的作用，将卵丘-卵母细胞复合物与 Delta14 还原酶抑制剂 AY9944-A-7 或 Delta7 还原酶抑制剂 BM15.766 一起培养。结果表明，这些抑制剂显着抑制卵丘细胞中孕酮的产生和卵母细胞减数分裂的进展。抑制作用在 1 microM AY9944-A-7 或 20 microM BM15.766 时达到最大值。添加20 ng/ml黄体酮克服了两种药物对卵母细胞减数分裂恢复的抑制作用。这些结果表明，卵丘细胞中促性腺激素诱导的 Delta14 还原酶和 Delta7 还原酶的表达和功能通过黄体酮依赖性途径有助于卵母细胞减数分裂的恢复。
Progesterone is produced from cholesterol in cumulus cells during meiotic resumption of porcine oocytes. In follicular cells, it has been shown that exogenous lipoprotein-bound cholesterol ester can be used for steroid hormone production. However, in serum-free medium, progesterone is also secreted by FSH- and LH-stimulated cumulus-oocyte complexes, suggesting that progesterone could be produced from de novo synthesized cholesterol in cumulus cells. In the present study, we investigated the expression of Delta14-reductase and Delta7-reductase, which are the members of the superfamily that converts acetyl-CoA to cholesterol in cumulus cells. The expression of both genes was analyzed by RT-PCR. Both Delta14-reductase mRNA and Delta7-reductase mRNA in cumulus cells, cultured until 4 h, were under the level of detection limit. In response to gonadotropins, both mRNA levels were dramatically up-regulated, reaching a maximum at 20 h. To clarify the role of induced enzymes in cumulus cells, cumulus-oocyte complexes were cultured with either Delta14-reductase inhibitor, AY9944-A-7, or Delta7-reductase inhibitor, BM15.766. The results indicated that these inhibitors significantly suppressed the progesterone production in cumulus cells and meiotic progression of oocytes. The inhibitory effects reached a maximum at 1 microM AY9944-A-7 or 20 microM BM15.766. The addition of 20 ng/ml progesterone overcame the inhibitory effects of both drugs on meiotic resumption of oocytes. These results imply that gonadotropin-induced expression and function of Delta14-reductase and Delta7-reductase in cumulus cells contribute to oocyte meiotic resumption via a progesterone-dependent pathway.