Putowski L T, Choi D, Mordacq J, Scherzer W J, Mayo K E, Adashi E Y, Rohan R M
Department of Obstetrics and Gynecology, University of Maryland School of Medicine, Baltimore 21201-1559, USA.
J Soc Gynecol Investig. 1995 Nov-Dec;2(6):735-42.
Despite the potential importance of insulin-like growth factor binding protein-5 (IGFBP-5) to follicular development, the hormonal regulation of this antigonadotropic IGFBP has not been investigated. Therefore, it was the objective of this study to eludicate the role of gonadotropins and estrogen in the in vivo regulation of IGFBP-5 mRNA expression.
Two models of follicular development in immature rats were used. Specifically, rats were hypophysectomized and treated with FSH and/or diethylstilbestrol (DES). Alternatively, terminal follicular development was induced in intact immature rats by pregnant mare serum gonadotropin (PMSG) and hCG. The IGFBP-5 mRNA in whole ovarian RNA was assayed by Northern blot hybridization. Localization of expression in PMSG and hCG-stimulated ovaries was further assessed by in situ hybridization.
Expression of IGFBP-5 mRNA was increased in ovaries from hypophysectomized rats. Treatment with FSH and/or DES did not alter the abundance of this mRNA. Treatment with PMSG induced a transient increase in IGFBP-5 expression that was localized in a subset of alpha-inhibin-negative follicles. At later times after PMSG, IGFBP-5 expression persisted in the surface epithelium but was not detected in large preovulatory follicles. In vitro studies affirmed the antigonadotropic action of IGFBP-5.
In vivo expression of IGFBP-5 in the rat ovary is moderated by hormonal treatment both in terms of total expression and follicular localization.
尽管胰岛素样生长因子结合蛋白-5（IGFBP-5）对卵泡发育具有潜在重要性，但这种促性腺激素抑制因子的激素调节尚未得到研究。因此，本研究的目的是阐明促性腺激素和雌激素在体内对IGFBP-5 mRNA表达的调节作用。
使用未成熟大鼠卵泡发育的两种模型。具体而言，将大鼠垂体切除并用促卵泡激素（FSH）和/或己烯雌酚（DES）进行处理。或者，通过孕马血清促性腺激素（PMSG）和人绒毛膜促性腺激素（hCG）诱导完整未成熟大鼠的终末卵泡发育。通过Northern印迹杂交法检测全卵巢RNA中的IGFBP-5 mRNA。通过原位杂交进一步评估PMSG和hCG刺激的卵巢中的表达定位。
垂体切除大鼠卵巢中IGFBP-5 mRNA的表达增加。用FSH和/或DES处理并未改变该mRNA的丰度。用PMSG处理诱导IGFBP-5表达短暂增加，其定位于一部分α-抑制素阴性卵泡中。在PMSG处理后的后期，IGFBP-5表达在表面上皮中持续存在，但在大的排卵前卵泡中未检测到。体外研究证实了IGFBP-5的促性腺激素抑制作用。
在大鼠卵巢中，IGFBP-5的体内表达在总表达和卵泡定位方面均受到激素处理的调节。
