Purpose: We previously reported the gene expression of epidermal growth factor (EGF) in the process of decidualization in the human endometrium. This study was undertaken to investigate the biological significance of transforming growth factor-alpha (TGF-alpha), which shares a significant sequence homology with EGF, in the regulation of decidualization.
Methods: The gene encoding TGF-alpha was analyzed by Northern blot hybridization in nonpregnant human endometria and decidua from 6 to 8 weeks of gestation as well as in cultured stromal cells with or without medroxyprogesterone acetate.
Results: No transcript was detected in proliferative and secretory endometrium, whereas a transcript of 4.8 kb, which was in agreement with the size of human prepro-TGF-alpha mRNA previously reported, was clearly detected in decidua. Transcript of 4.8 kb was also detected in vitro in medroxyprogesterone acetate (MPA)-induced decidual cells, while no TGF-alpha transcript was found in endometrial stromal cells cultured without MPA.
Conclusions: These results suggest that the gene expression of TGF-alpha in uterine stromal cells is enhanced by stimulation from sex steroids and that TGF-alpha, like EGF, functions as one of the regulatory factors for decidualization in the human uterus.