ABSTRACT
UNLABELLED: 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 analyse the effects of genistein and daidzein on estrogen receptor (ER)alpha- and ERbeta-mRNA and protein expression in the endometrium of premenopausal women. MATERIALS AND METHODS: Glandular endometrial cells were isolated from endometrial biopsies obtained from regularly menstruating women undergoing gynaecological abrasio or hysterectomy. Cells were stimulated with single doses of genistein or daidzein. ERalpha- and ERbeta-protein expression were determined by immunocytochemical analysis. In addition ERalpha- and ERbeta-mRNA expression were determined by quantitative real-time RT-PCR. Quantification was carried out by the deltadelta 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 ERalpha- and ERbeta-mRNA expression. The effects were time- and dose-dependent. Detection of ERalpha- and ERbeta-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 ERalpha- and an increase in ERbeta-mRNA expression after stimulation with tested phytoestrogens. Our results are in line with findings that phytoestrogens act as anti-estrogens in organs expressing more ERalpha and as estrogens in ERbeta-presenting organs.
