Gene expression of epidermal growth factor in human endometrium during decidualization

Although there are some reports, including our previous study, indicating the existence and biological action of epidermal growth factor (EGF) in human decidua, the site of its synthesis remains unknown. To clarify the EGF production during decidualization at a molecular level, gene expression of EGF in human endometrium/decidua was examined by Northern blot analysis and in situ hybridization. Northern blot hybridization using 32P-labeled human prepro-EGF complementary DNA was carried out for nonpregnant human endometria from hysterectomized uteri of leiomyoma, decidua from early pregnancy, and in vitro decidualized endometrial cells by medroxyprogesterone acetate (MPA). Although no hybridized band was found in the proliferative and secretory phase endometria, a specific band of 5 kilobases, in agreement with the size of human prepro-EGF messenger ribonucleic acid, was detected in decidua of early pregnancy as well as in in vitro MPA-induced decidual cells. In situ hybridization revealed that prepro-EGF messenger ribonucleic acid was observed in the stromal cells of decidua. These results demonstrate that the EGF gene is expressed in the process of decidualization, suggesting that EGF may play an important role in the decidualization process of human endometrium.