摘要
探讨小剂量雌激素对老年雌性大鼠下丘脑雌激素受体（ER）表达及β-内啡肽肚（β-EP）的影响。建立自然衰老的18月龄雌性大鼠模型，用放射配体结合法检测ER，用Northernblot分析ERmRNA的改变，用放射免疫分析法检测β-EP含量。结果表明：雌激素对ER和ERmRNA呈显著的负向调节作用，ER表达被抑制；β-EP水平明显提高。雌激素的这些作用与其剂量之间并非简单的线性关系。提示：外源性雌激素对体内的神经内分泌平衡有多种影响，在进行雌激素替代治疗时应尽可能选择小剂量。
Estrogen replacement therapy (ERT) has been widely used in postmanopaus women and oophorectomy women. It was demonstrated that ERT rose the levels of serum estradiol and beta-endorphin(βEP).In the present study,the effect of small dose estradiol on estrogen receptor(ER)expression andβ-EP in Hypothalamus of aging female rats was observed.ER proteins were determined by radiolignad binding assay,ER mRNA was analyzed by Northern blot analysis and the levels ofβ-Ep was detected by immunohistochemistry.ER protein and ER mRNA in hypothalamus of 18 months age female rats were down regulated by exoestradiol.The levels ofβ-EP in these rats were increased at the same time.In conclusion,exoestrogen may increase the level ofβ-EP in hypothalamus during down-regulating ER expression.The results suggested that ERT patients would choose exoestradiol dose as small as possible.
