1996 年 43 巻 6 号 p. 621-628
To analyze direct effects of estrogen on gene expressions of Inhibin subunits in vitro, the mRNA levels of inhibin a- and βA-subunits were measured in rat granulosa cells cultured with FSH or estradiol. Through the culture process of the granulosa cells with serum-free medium, both the α- and βA subunit mRNAs decreased, and were partially increased again by adding FSH to the culture medium. To examine whether these FSH effects are mediated via estrogen production, estradiol or tamoxifen was added to the cultured granulosa cells. After 36-h culture with estradiol, the inhibin α-subunit decreased but the Inhibin βA-subunit increased, in a dose-responsive manner. Tamoxifen showed completely opposite effects to estradiol, and a combination of estradiol and tamoxifen resulted in similar levels of inhibin-α and -βA mRNAs to the control. These results indicate that estrogen would by a certain pathway affect gene expressions of the inhibin subunits in the rat granulosa cells, and may regulate the production of inhibin and activin through the paracrine system.
