ABSTRACT
The effects of mifepristone (RU486) on the productions of plasminogen activator and progesterone in rat granulosa cells and luteal cells were studied by fibrin overlay method and radioimmunoassay method. The results showed that RU486 could significantly antagonize tPA activity and progesterone production enhanced by human chorionic gonadotropin (hCG). Secretion of tPA from luteal cells was significantly promoted by RU486 with or without prostaglandin F2a (PGF2α), but progesterone production in luteal cells was markedly inhibited with the same treatment. With method of tissue culture, the results showed that RU486 was capable of stimulating tPA and urokinase (uPA) activity in endometrium of pregnant rats. These findings indicated that antifertility of RU486 might be partly mediated through plasminogen activator-plasminogen activator inhibitor system.