Elevated estrogen receptor expression in hypothalamic preoptic area decreased by electroacupuncture in ovariectomized rats

► Hypothalamic GnRH release and mRNA expression increased in ovariectomized rats. ► Expression of hypothalamic estrogen receptors increased in ovariectomized rats. ► EA restrained the elevated expression of estrogen receptors in ovariectomized rats. ► EA inhibited the increased GnRH release and mRNA level in ovariectomized rats. In the present study, effects of electroacupuncture (EA) on estrogen receptor alpha (ERα) and beta (ERβ) mRNA and protein expression in the hypothalamus of ovariectomized (OVX) rats were detected by quantitative real-time reverse transcription PCR (qRT-PCR) and western blot analysis. Gonadotropin-releasing hormone (GnRH) release and GnRH mRNA level in hypothalamic preoptic area (POA) were evaluated by push–pull perfusion and qRT-PCR. Our results showed that elevated mRNA and protein expression of ERα and ERβ in hypothalamus were restrained following EA treatment in OVX rats. EA treatment also inhibited GnRH release and GnRH mRNA levels in OVX rats. These results provide novel evidence that EA treatment down regulates the expression of hypothalamic estrogen receptors (ERs), thus restores the response of GnRH neurons to estrogen depression, and partially resets the negative feedback of estrogen to hypothalamus–pituitary–ovary axis (HPOA) in OVX rats, which may be a critical mechanism for EA on female reproductive disorders.