Veney S L, Rissman E F
Department of Biology, University of Virginia, Charlottesville, Virginia, 22903, USA.
Horm Behav. 1998 Jun;33(3):151-62. doi: 10.1006/hbeh.1998.1446.
Estrogens are produced by the aromatization of androgens. These steroids exert their actions after binding to their receptors. Past studies have shown that estrogen receptors (ER) and aromatase enzyme (AROM) reside in many of the same brain regions. Few studies, however, have examined the neural co-localization of these important components involved in estrogen-activated behaviors. In the present study we examined the co-localization of ER and AROM immunoreactive (ir) neurons in musk shrew (Suncus murinus) brains. Data were collected from a representative section from three neural regions, the bed nucleus of the stria terminalis (BNST), medial preoptic area (mPOA), and ventromedial nucleus of the hypothalamus (VMN). Here we report a sex difference in the number of ER-ir neurons from the analyzed section of the mPOA and BNST. Females have more ER-ir neurons in the mPOA and males have more in the BNST. In the sections we examined, males tended to have more aromatase containing neurons than females. Although there were no significant differences in the numbers of double-labeled cells, the VMN contains the greatest percentage of these cells in both males and females; followed by the mPOA and the BNST. In addition, in the mPOA of both sexes, a distinct nucleus of aromatase containing neurons which was devoid of ER immunoreactivity was noted. Area measurements of the AROM-ir nucleus showed that it was significantly larger in males than in females. Taken together, these data suggest that there is not extensive cellular co-localization of estrogen receptors and aromatase enzyme in the musk shrew brain. However, the presence of other genomic forms of ER (membrane and/or ERbeta) in AROM containing neurons has not been ruled out by this study. Thus, we hypothesize that estrogens produced in brain affect behavior by binding to ER in neurons other than those that contain aromatase enzyme.
雌激素由雄激素经芳香化作用产生。这些类固醇在与它们的受体结合后发挥作用。过去的研究表明，雌激素受体（ER）和芳香化酶（AROM）存在于许多相同的脑区。然而，很少有研究考察这些参与雌激素激活行为的重要成分在神经上的共定位情况。在本研究中，我们检测了麝鼩（Suncus murinus）大脑中ER和AROM免疫反应性（ir）神经元的共定位。数据收集自三个神经区域的代表性切片，即终纹床核（BNST）、内侧视前区（mPOA）和下丘脑腹内侧核（VMN）。在这里我们报告，在mPOA和BNST的分析切片中，ER-ir神经元数量存在性别差异。雌性在mPOA中有更多的ER-ir神经元，而雄性在BNST中有更多。在我们检查的切片中，雄性往往比雌性有更多含芳香化酶的神经元。尽管双标记细胞数量没有显著差异，但VMN在雄性和雌性中都含有这些细胞的最大比例；其次是mPOA和BNST。此外，在两性的mPOA中，都发现了一个不含ER免疫反应性的独特的含芳香化酶神经元核。对AROM-ir核的面积测量显示，雄性的该核明显大于雌性。综上所述，这些数据表明在麝鼩大脑中雌激素受体和芳香化酶没有广泛的细胞共定位。然而，本研究并未排除含AROM的神经元中存在其他基因组形式的ER（膜性和/或ERβ）的可能性。因此，我们推测大脑中产生的雌激素通过与含芳香化酶的神经元以外的神经元中的ER结合来影响行为。
