본 실험에서 첫째 , α 및 FSHβ subunit 생합성이 혈중 FSH 분비와 같은 양상으로 조절되는지 둘째 , 난소홀몬이 전사단계에서 α 및 FSHβ subunit 생합성을 조절하는지 셋째, 서로 다른 유전자에 의하여 만들어진 α 및 FSHβ subunit 생합성이 같은 기전으로 조절되는지를 규명하기 위하여 본 실험을 시행하여 다음과 같은 결과를 얻었다. 1. 난소제거 후 시간경과에 따라 FSH 분비와 마 찬가지로 α 및 FSHβ subunit mRNA 농도가 증 가하였다. 2. 난소제거로 증가된 FSH 분비는 estradiol 1회 투여로 영향을 받지않았으나 progesterone 투여로는 억제되었다. 난소제거 후 증가된 α subunit mRNA 농도는 estradiol 및 progesterone 투여로 감소하는 경향을 보였으나 FSHβ subunit mRNA 농도는 pr-ogesterone투여로 유의하게 억제되었다. 난소홀몬 연속투여는 난소제거로 증가된 혈중 FSH 및 subunit mRNA 농도를 난소홀몬 1회 투여시와 비슷하게 억제하였으나 더욱 강력한 억제현상을 보였다. 이상의 결과로 보아 FSH subunit 생합성은 난소 홀몬에 의하여 전이전단계에서 조절되나 progesterone의 작용이 더 강하며 , α subunit 및 FSHβ subunit 생합성이 각각 다른 기전에 의하여 조절된다 고 생각된다.

Follicle stmulating hormone ( FSH ) consist of α and β subunits, which are encoded by se-parate 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 inhibit FSH secretion selectively. However , little is known about their regulation of the biosynthesis of FSH subunits at transcriptional and posttranscriptional levels. In the pre-sent study , we studied the time course of changes in α and FSHβ subunit mRNA concentrati-ons after castration and the effects of ovarian steroids of changes in α and FSHβ subunit mRNA concentrations after castration and the effects of ovarian steroids on α and FSHβ subunit mRNA in ovariectomized rats in order to determine Whether FSH subunit synthesis is modulated at the pretranslational levels, and whether synthesis and secretion are differently regulated. Results are as follows： 1. The time course of the rise in the steady state α subunit and FSHβ subunit mRNA levels were observed after ovariectomy, which paralleled the increases in serum and pituitary FSH concentrations. The time course experiments revealed differences in the patterns of α and FSHβ subunit mRNA responses , the rise in FSHβ subunit mRNA levels being more pro- minent than the rise in α subunit mRNA. 2. FSHβ mRNA levels were negatively regulated by the single injection of progesterone but not by estradiol , suggesting that FSHβ subunit mRNA seemed to be more sensitive to ne-gative feedback by progesterone than estradiol. Similar results were obtained by the continuous treatment of ovarian steroids for 1∼4 days , but inhibition was more prominent with continuous treatment. It is , therefore , concluded that estradiol and progesterone inhibit the synthesis of FSH at the pretranslational level by modulating the steady state levels of α and FSHβ subunit mRNA , progesterone effect being more promiment than that of estradiol and α and FSHβ subunit are regulated in a different manner.