Rat ovarian insulin-like growth factor II gene expression is theca-interstitial cell-exclusive: hormonal regulation and receptor distribution.
Rat ovarian insulin-like growth factor II gene expression is theca-interstitial cell-exclusive: hormonal regulation and receptor distribution.
复制标题
大鼠卵巢胰岛素样生长因子 II 基因表达是卵泡膜间质细胞独有的：激素调节和受体分布。
作者：
E. Hernández;C. Roberts;A. Hurwitz;D. Leroith;E. Adashi
虽然胰岛素样生长因子 (IGF)-I 在卵巢生理学中的潜在作用已被广泛研究，但对 IGF-II 的关注相对有限，IGF-II 在成熟大鼠卵巢中的存在受到质疑。在本研究中，我们重新评估了大鼠卵巢 IGF-II 基因表达、其细胞定位、激素调节和受体相互作用位点。在未成熟和成熟的完整大鼠的整个卵巢中检测到 IGF-II mRNA。细胞定位研究显示 IGF-II 转录物存在于卵泡膜间质细胞中，而非颗粒细胞（IGF-I 基因表达位点）中。相比之下，I 型和 II 型 IGF 受体基因表达没有细胞选择性，这两种基因在颗粒细胞和卵泡膜间质细胞中都可以清楚地检测到。用己烯雌酚对未成熟垂体切除大鼠进行体内治疗，可降低卵巢 IGF-II mRNA 水平，同时增加 IGF-I mRNA 水平。总而言之，这些和之前的观察揭示了卵巢 IGF 基因表达的细胞定位和激素调节的根本差异，因为 IGF-II 基因表达（与 IGF-I 不同）是卵泡膜间质（而不是颗粒）细胞特异性的，并且在雌激素刺激下受到下调（而不是上调）调节。相比之下，I 型和 II 型 IGF 受体存在于大鼠卵巢的两种体细胞类型上。这些观察结果与以下观点一致：卵泡膜间质细胞来源的 IGF-II 可能不仅发挥自分泌作用，而且还可以作为多种信号之一，通过这些信号，雄激素产生细胞可以以旁分泌方式与相邻的颗粒细胞区室进行交流。
While the potential role of insulin-like growth factor (IGF)-I in ovarian physiology has been extensively studied, relatively limited attention has been paid to IGF-II the very presence of which in the mature rat ovary has been questioned. In the present study, we have reevaluated rat ovarian IGF-II gene expression, its cellular localization, hormonal regulation, and site(s) of receptor interaction. IGF-II mRNA was detected in whole ovaries from immature as well as mature intact rats. Cellular localization studies revealed IGF-II transcripts in theca-interstitial but not granulosa cells (a site of IGF-I gene expression). In contrast, no cellular selectivity was noted for Type I and Type II IGF receptor gene expression, both of which were clearly detectable in both granulosa and theca-interstitial cells. In vivo treatment of immature hypophysectomized rats with diethylstilbestrol reduced ovarian IGF-II mRNA levels while increasing IGF-I mRNA levels. Taken together, these and previous observations reveal fundamental differences in the cellular localization and hormonal regulation of ovarian IGF gene expression in that IGF-II gene expression (unlike IGF-I) is theca-interstitial (rather than granulosa) cell-specific, and is subject to down (as opposed to up) regulation in response to estrogenic stimulation. In contrast, Type I and Type II IGF receptors exist on both somatic cell types of the rat ovary. These observations are consistent with the view that IGF-II of theca-interstitial cell origin may not only play an autocrine role but may also serve as one of several signals through which this androgen-producing cell may communicate in a paracrine fashion with the adjacent granulosa cell compartment.
DOI：
10.1073/pnas.84.9.2643
发表时间：
1987-05
影响因子：
11.1
作者：
K. Ramasharma;C. Li
通讯作者：
K. Ramasharma;C. Li