Kishi Hisashi, Ohshima Ken-ichi, Itoh Mariko, Tsukada Junko, Arai Koji Y, Nakano Saeko, Watanabe Gen, Taya Kazuyoshi
Genome Research Department, National Institute of Agrobiological Sciences, Ibaraki 305-8602, Japan.
Zoolog Sci. 2002 Feb;19(2):225-32. doi: 10.2108/zsj.19.225.
In the present study, changes in localization of each inhibin subunit in the ovary were investigated during the estrous cycle of the golden hamster. The effect of LH surge on changes in localization in inhibin alpha subunit in the ovary was also investigated. Inhibin alpha subunit was localized in granulosa cells of various stages of follicles throughout the estrous cycle. Inhibin alpha subunit was also present in numerous interstitial cells on days 1 and 2 (day 1 = day of ovulation), but the number of positive interstitial cells was fewer on days 3 and almost disappeared on day 4 of the estrous cycle. Newly formed luteal cells were also positive for inhibin alpha subunit on days 1 and 2. On the other hand, positive reactions for inhibin beta A and beta B subunits were only present in the granulosa cells of healthy antral follicles. However, a positive reaction for inhibin beta B subunit in peripheral mural granulosa cells disappeared on days 3 and 4 of the estrous cycle. Treatment with LHRH-AS at 1100 h on day 4 completely blocked the luteinizing hormone (LH) surge and ovulation, although relatively high concentrations of plasma follicle-stimulating hormone (FSH) were maintained throughout the experiment. There were few positive reactions for inhibin alpha subunit in theca and interstitial cells 24 hr after LHRH-AS injection. The effect of LHRH-AS treatment was blocked by a single injection of 10 IU human chorionic gonadotropin. These results suggest that the major source of dimeric inhibin in the cyclic hamster was granulosa cells of healthy antral follicles. Different distribution pattern of inhibin beta A from beta B subunits in large antral follicles on days 3 and 4 of the estrous cycle suggests different secretion patterns of inhibin A from B on these days. Furthermore, the LH surge may be an important factor to induce production of inhibin alpha subunit in interstitial cells of the cyclic hamster.
在本研究中，研究了金黄仓鼠发情周期中卵巢内各抑制素亚基定位的变化。还研究了促黄体生成素（LH）峰对卵巢中抑制素α亚基定位变化的影响。在整个发情周期中，抑制素α亚基定位于不同阶段卵泡的颗粒细胞中。在发情周期的第1天和第2天（第1天=排卵日），抑制素α亚基也存在于大量间质细胞中，但在第3天阳性间质细胞数量减少，在发情周期的第4天几乎消失。新形成的黄体细胞在第1天和第2天对抑制素α亚基也呈阳性反应。另一方面，抑制素βA和βB亚基的阳性反应仅出现在健康窦状卵泡的颗粒细胞中。然而，发情周期第3天和第4天，周边壁层颗粒细胞中抑制素βB亚基的阳性反应消失。在第4天1100 h用促性腺激素释放激素拮抗剂（LHRH-AS）处理完全阻断了促黄体生成素（LH）峰和排卵，尽管在整个实验过程中血浆促卵泡生成素（FSH）维持在相对较高的浓度。LHRH-AS注射后24小时，卵泡膜细胞和间质细胞中抑制素α亚基的阳性反应很少。单次注射10 IU人绒毛膜促性腺激素可阻断LHRH-AS处理的效果。这些结果表明，周期性仓鼠中二聚体抑制素的主要来源是健康窦状卵泡的颗粒细胞。发情周期第3天和第4天，大窦状卵泡中抑制素βA和βB亚基的分布模式不同，表明这几天抑制素A和B的分泌模式不同。此外，LH峰可能是诱导周期性仓鼠间质细胞产生抑制素α亚基的重要因素。
