Stimulation of endometrial glandular cells with genistein and daidzein and their effects on ERα- and ERβ-mRNA and protein expresion

Phytoestrogens seem to have estrogen-like effects in the human body as their structure is very similar to those estrogens produced in human glands. The aim of the present study was to ana se the effects of genistein and daidzein on estrogen receptor (ER)alpha- and ER beta-mRNA and protein expression in the endometrium of premenopausal women. Materials and Methods: Glandular endometrial cells were isolated from endomettial biopsies obtained from regularly menstruating women undergoing gynaecological abrasio or hysterectomy. Cells were stimulated with single doses of genistein or daidzein. ER alpha- and ER beta-protein expression were determined by immunocytochemical analysis. In addition ER alpha- and ER beta-mRNA expression were determined by quantitative real-time RT-PCR, Quantification was carried out by the Delta Delta C-T-method using glyceraldehyde phosphate dehydrogenase (GAPDH) as housekeeping gene. Results: Endometrial glandular cells responded to stimulation with genistein and daidzein by alteration of both ER alpha- and ER beta-mRNA expression. The effects were time- and dose-dependent. Detection of ER alpha- and ER beta-protein expression by immunocytochemistry showed a dose-dependent regulation after stimulation of isolated endometrial cells with phytoestrogens. Discussion: According to our results, we suggest that ER expression in endometrial glandular cells is regulated by genistein and daidzein on the mRNA and protein levels. We could detect a decrease in ER alpha- and an increase in ER beta-mRNA expression after stimulation with tested phytoestrogens. Our results are in line with findings that phytoestrogens act as anti-estrogens in organs expressing more ER alpha and as estrogens in ER beta-presenting organs.