Mitsushima Dai, Funabashi Toshiya, Kimura Fukuko
Department of Neuroendocrinology, Yokohama City University, Graduate School of Medical Sciences, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan.
Biochem Biophys Res Commun. 2003 Jul 25;307(2):248-53. doi: 10.1016/s0006-291x(03)01171-9.
We examined the effect of estrogen on the expression of aryl-hydrocarbon receptor (AhR) and two types of AhR nuclear translocator (Arnt1 and Arnt2) mRNAs in the hypothalamus of ovariectomized rats. Northern blotting demonstrated that, in the mediobasal hypothalamus, a subcutaneous injection of 20 microg estradiol benzoate (E(2)) significantly increased the expression of Arnt2 mRNA, but induced no significant changes in the expression of AhR and Arnt1 mRNAs. The expression of Arnt2 mRNA was significantly increased at 4, 24, and 72h after the injection. Immunocytochemical study revealed that the number of Arnt2 immunoreactive cells was also significantly increased at 72h after the injection. Conversely, in the preoptic area, injection of E(2) did not cause significant changes in the expression of any of the three mRNAs. These observations suggest that estrogen regulates Arnt2 expression in the mediobasal hypothalamus and modulates the toxic action of dioxins in rats.
我们研究了雌激素对去卵巢大鼠下丘脑芳烃受体（AhR）及两种类型的AhR核转运蛋白（Arnt1和Arnt2）mRNA表达的影响。Northern印迹法显示，在中基底下丘脑，皮下注射20μg苯甲酸雌二醇（E₂）可显著增加Arnt2 mRNA的表达，但对AhR和Arnt1 mRNA的表达无显著影响。注射后4、24和72小时，Arnt2 mRNA的表达显著增加。免疫细胞化学研究表明，注射后72小时，Arnt2免疫反应性细胞数量也显著增加。相反，在视前区，注射E₂对三种mRNA中的任何一种表达均未引起显著变化。这些观察结果表明，雌激素调节中基底下丘脑的Arnt2表达，并调节大鼠体内二噁英的毒性作用。
