Yoshimura Y, Nakamura Y, Oda T, Ando M, Ubukata Y, Karube M, Koyama N, Yamada H
Department of Obstetrics and Gynecology, Kyorin University School of Medicine, Tokyo, Japan.
J Reprod Fertil. 1992 Aug;95(3):803-12. doi: 10.1530/jrf.0.0950803.
The involvement of cyclic adenosine monophosphate (cAMP) in mammalian oocyte maturation was assessed using cultures of rabbit cumulus-oocyte complexes and perfused rabbit ovaries. Rabbit cumulus-oocyte complexes were cultured in Brackett's medium with or without forskolin at 10(-4), 10(-5) or 10(-6) mol l-1 for 3-6 h. At 3 or 4 h spontaneous meiotic maturation was significantly (P < 0.05) inhibited by forskolin at 10(-4) mol l-1. With prolonged incubation, spontaneous maturation progressed despite exposure to forskolin. In the second experiment ovaries were perfused for 12 h with forskolin (10(-4), 10(-5) or 10(-6) mol l-1) or medium alone. Neither ovulation nor degeneration of follicular oocytes occurred in any perfused ovary. The percentage of follicular oocytes achieving germinal vesicle breakdown was significantly (P < 0.001) increased in response to forskolin in a dose-related manner. In an additional experiment, ovaries were perfused with forskolin at 10(-4) mol l-1. A significant increase in the cAMP content in the follicle was observed within 30 min, but the ability to produce cAMP in response to forskolin decreased as the duration of perfusion was increased. Intraoocyte cAMP increased significantly within 30 min and reached its maximum 2 h after exposure to forskolin. Thereafter, cAMP levels in the oocytes decreased abruptly. This drop in intraoocyte cAMP concentration was followed by the resumption of meiosis. The alterations of intraoocyte cAMP contents following exposure to hCG in vivo paralleled those observed in the ovaries perfused with forskolin. These data suggest that a transient, but not continuous, increase in cAMP concentration after the gonadotrophin surge may be required to initiate oocyte maturation.
利用兔卵丘 - 卵母细胞复合体培养物和灌注兔卵巢来评估环磷酸腺苷（cAMP）在哺乳动物卵母细胞成熟过程中的作用。将兔卵丘 - 卵母细胞复合体在含有或不含有10⁻⁴、10⁻⁵或10⁻⁶mol/L福斯高林的布雷克特培养基中培养3 - 6小时。在3或4小时时，10⁻⁴mol/L的福斯高林显著（P < 0.05）抑制了自发减数分裂成熟。随着孵育时间延长，尽管暴露于福斯高林，自发成熟仍在进行。在第二个实验中，用福斯高林（10⁻⁴、10⁻⁵或10⁻⁶mol/L）或单独的培养基对卵巢进行12小时灌注。在任何灌注的卵巢中均未发生排卵或卵泡卵母细胞退化。卵泡卵母细胞实现生发泡破裂的百分比因福斯高林而呈剂量相关方式显著（P < 0.001）增加。在另一个实验中，用10⁻⁴mol/L的福斯高林灌注卵巢。在30分钟内观察到卵泡中cAMP含量显著增加，但随着灌注时间延长，对福斯高林产生cAMP的能力下降。卵母细胞内cAMP在30分钟内显著增加，并在暴露于福斯高林后2小时达到最大值。此后，卵母细胞中的cAMP水平突然下降。卵母细胞内cAMP浓度的这种下降之后是减数分裂的恢复。体内暴露于hCG后卵母细胞内cAMP含量的变化与用福斯高林灌注的卵巢中观察到的变化相似。这些数据表明，促性腺激素激增后cAMP浓度的短暂而非持续增加可能是启动卵母细胞成熟所必需的。
