| Effects of GnRH on FSH Release and Subunit Synthesis in Cultured Rat Anterior Pituitary Cells. |
|
Y K Kim, Y S Park |
|
|
| Abstract |
|
Follicle stimulating hormine (FSH) is a one of the pituitary gonadotropins that plays an important role in the regulation of gametogenesis and estrogen biosynthesis. It consists of alpha and beta subunit, which are encoded by separate genes. Pituitary release of FSH appears to be regulated by the hypothalamic GnRH and the gonadal steroid hormones. In addition, inhibin and follistatin produced by the gonad have been known to selectively inhibit FSH secretion. However, little is known about their regulation of FSH subunit synthesis at transcriptional and posttranscriptional levels. It has been shown that in vivo paradigms such as ovariectomy and ovarian steroid replacement, levels of FSH generally reflect the transcriptional activity of subunit genes, and ovarian steroids negatively regulate FSH synthesis at the pretranslational level by influencing the steady state levels of FSH alpha and beta subunit mRNA. The present study was, therefore, attempted to determine whether GnRH regulates FSHbeta subunit synthesis in the similar manner to LH at the transcriptional level by using primary pituitary cell culture. The results showed that GnRH stimulated FSHbeta release from cultured pituitary cells in a dose-dependent manner as well as time-dependent manner. The treatment of pituitary cells with GnRH tended to increase FSHbeta subunit mRNA level but increases were not statistically significant suggesting that, unlike LH, GnRH does not seem to play a major role in FSH synthesis by influencing the steady state mRNA level of FSHbeta subunit. From these results, it is, therefore, concluded that GnRH does not seem to be a major regulator for FSH synthesis. |
| Key Words:
GnRH, FSH release, FSHbeta subunit, rat anterior pituitary cells |
|
Full text via DOI
Download Citation
