Shughrue P J, Bushnell C D, Dorsa D M
Department of Pharmacology, University of Washington, Seattle.
Endocrinology. 1992 Jul;131(1):381-8. doi: 10.1210/endo.131.1.1612018.
Variations in levels of estrogen receptor mRNA were investigated in the medial preoptic nucleus, arcuate nucleus, and ventromedial nucleus of the hypothalamus throughout the phases of the female estrous cycle and compared with those in ovariectomized female and intact male rats. Female Wistar rats were killed during estrus, metestrus, diestrus, or proestrus or 72 h after ovariectomy as were a group of intact male rats. Brains were removed and frozen, and 20-microns cryostat sections were thaw-mounted onto slides and hybridized with a 35S-labeled antisense estrogen receptor probe. Section-mounted slides were processed, apposed to x-ray film, then dipped in liquid emulsion, and quantified. After exposure, estrogen receptor mRNA was detected in several brain regions, including the medial preoptic nucleus, arcuate nucleus, and ventromedial nucleus of the hypothalamus. Estrogen receptor mRNA levels in the medial preoptic nucleus were highest during estrus and metestrus, attenuated at diestrus, and low during proestrus. In contrast, the hybridization signal in the arcuate and ventromedial nuclei was low during estrus and then gradually increased throughout the cycle until it peaked during proestrus. Ovariectomized females exhibited an elevated level of estrogen receptor mRNA in all brain regions investigated. Hybridization signal in male medial preoptic nucleus and ventromedial nucleus was reduced compared with those in both intact and ovariectomized females. Estrogen receptor mRNA levels in the arcuate nucleus were similar to those in intact females, but less than those in ovariectomized animals. The results of these studies demonstrate that estrogen receptor mRNA levels are sexually dimorphic, vary during the estrous cycle, and increase after ovariectomy. Furthermore, these results indicate that the magnitude and direction of change observed during the estrous cycle are region specific and suggest that factors other than endogenous estrogen levels differentially modulate estrogen receptor mRNA expression in the hypothalamus.
在雌性大鼠发情周期的各个阶段，研究了下丘脑内侧视前核、弓状核和腹内侧核中雌激素受体mRNA水平的变化，并与卵巢切除的雌性大鼠和完整雄性大鼠中的水平进行比较。雌性Wistar大鼠在发情期、动情后期、间情期、发情前期或卵巢切除后72小时处死，一组完整雄性大鼠也同时处死。取出大脑并冷冻，将20微米的低温恒温器切片解冻后贴在载玻片上，并用35S标记的反义雌激素受体探针进行杂交。将贴有切片的载玻片进行处理，与X射线胶片相对放置，然后浸入液体乳剂中并进行定量分析。曝光后，在下丘脑的几个脑区检测到雌激素受体mRNA，包括内侧视前核、弓状核和腹内侧核。内侧视前核中的雌激素受体mRNA水平在发情期和动情后期最高，在间情期减弱，在发情前期较低。相反，弓状核和腹内侧核中的杂交信号在发情期较低，然后在整个周期中逐渐增加，直到在发情前期达到峰值。卵巢切除的雌性大鼠在所有研究的脑区中雌激素受体mRNA水平均升高。与完整雌性大鼠和卵巢切除雌性大鼠相比，雄性内侧视前核和腹内侧核中的杂交信号降低。弓状核中的雌激素受体mRNA水平与完整雌性大鼠中的相似，但低于卵巢切除动物中的水平。这些研究结果表明，雌激素受体mRNA水平具有性别差异，在发情周期中会发生变化，并且在卵巢切除后会增加。此外，这些结果表明，在发情周期中观察到的变化幅度和方向具有区域特异性，并表明除内源性雌激素水平外的其他因素会差异性地调节下丘脑雌激素受体mRNA的表达。
