Coordinated regulation of tissue type plasminogen activator and plasminogen activator inhibitor type-1 gene expression in hypophysectomized rat ovaries during GnRHa-induced ovulation.
In this study we have demonstrated that both granulosa and theca-interstitial cells of hypophysectomized rat ovaries are capable of synthesizing tPA and PAI-1. Injection of a GnRH agonist can markedly induce these gene expressions in the ovary in a cell-specific and time-coordinated manner, so that a surge of tPA mRNA and its activity in both granulosa and theca-interstitial cells was obtained just prior to ovulation. Theca-interstitial cells make PAI-1 become the most active in the ovary. Both the amount PAI-1 mRNA and its activity in the cells reach the maximum level 6 h before the tPA peak. By contrast, granulosa cells produce only a little amount of PAI-1 (most increase tPA activity), and both PAI-1 mRNA and activity in the cells reach the maximum after ovulation. The coordinated regulation of tPA and PAI-1 in the ovary may fine-tune the peak of tPA activity which may be important for the regulation of the ovulatory process. The changes of tPA and PAI-1 in the ovarian cells of hypophysectomized rats during GnRHa-induced ovulation are similar to that in intact rats during hCG-induced ovulation, suggesting that the ovulatory process can be modulated by different regulatory signals mediated by influencing the coordinated expression of both tPA and PAI-1.
Liu
Y X
YX
State Key Laboratory of Reproductive Biology, Academia Sinica, Beijing, PRC.
Liu
K
K
Peng
X R
XR
Ny
T
T
D000818:Animals; D005260:Female; D005786:Gene Expression Regulation; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D006107:Granulosa Cells / Q000378:metabolism; D007016:Hypophysectomy; D010060:Ovulation / Q000187:drug effects / Q000378:metabolism*; D017395:Plasminogen Activator Inhibitor 1 / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013799:Theca Cells / Q000378:metabolism; D010959:Tissue Plasminogen Activator / Q000096:biosynthesis* / Q000235:genetics
D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; D007987:Gonadotropin-Releasing Hormone; D010959:Tissue Plasminogen Activator