Down-regulation of estrogen receptor mRNA in endometrium by estrogen and its mechanism

Objective To investigate the effects of estrogen on expression of estrogen receptor α ERα mRNA in endometrium and its possible mechanism. Methods Primarily-cultured human endometrium was exposed to estrogen and tamoxifen respectively. RT-PCR analysis was performed to observe the expression of ERα and DNA methyltransferase 3b DNMT3b mRNA. Results The relative expression levels of ERα mRNA in estrogen group was significantly lower than that in the control group 0.17±0.03 vs 0.27±0.08 t=2.69 P0.05 while there was no significant difference between those in tamoxifen group and control group 0.19±0.05 vs 0.27±0.08 t=2.23,P0.05. There was no significant difference in the expression of DNMT3b mRNA among three groups F=0.52,P0.05. Conclusion ERα mRNA expression in endometrium can be down-regulated by exogenous estrogen but not tamoxifen and the effect of estrogen on the DNMT3b mRNA expression might be not significant.