SEX STEROIDS REGULATE THE EXPRESSION OF PLASMINOGEN-ACTIVATOR INHIBITOR-1 AND ITS MESSENGER-RNA IN FIBROBLASTS DERIVED FROM UTERINE ENDOMETRIUM

In order to clarify a role of stromal cells in sex steroidal neovascul arization, plasminogen activator inhibitor (PAI)-1 [an inhibitor of ti ssue-type plasminogen activator (tPA) and urokinase-type plasminogen a ctivator (uPA)] and its messenger ribonucleic acid (mRNA) were analyse d in fibroblasts derived from uterine endometrium as a model for endom etrial stromal cells under the influence of sex steroids. The determin ations were carried out by an enzyme-linked immunosorbent assay (ELISA ) and reverse transcription-polymerase chain reaction-Southern blottin g, respectively. In the fibroblasts, either estradiol or progestogens (progesterone, medroxy progesterone acetate or 17 alpha-hydroxyprogest erone) induced expressions of PAI-1 and its mRNA, and their combinatio n further increased their expression by approximately twofold. PAI-1 f rom endometrial stromal cells under the influence of sex steroids migh t contribute to endometrial neovascularization through its effect on e ndothelial cells in endometrial vessels.