Roselli C E, Horton L E, Resko J A
Endocrinology. 1985 Dec;117(6):2471-7. doi: 10.1210/endo-117-6-2471.
Conversion of androgen to estrogen in the rat brain is catalyzed by aromatase enzymes. The maximum concentrations of these enzymes are found within the hypothalamus and amygdala, where they appear to play an important role in the process by which androgens affect both behavior and neuroendocrine function. In the present study, we measured the levels of aromatase activity (AA) in 20 nuclei and brain regions of the adult rat brain. Individual nuclei were microdissected from 600-micron frozen sections. Tissues from 3 animals were pooled, and AA was measured by an in vitro radiometric assay that quantifies the stereospecific production of 3H2O from [1 beta-3H]androstenedione as an index of estrogen formation. We report that AA is heterogeneously distributed within the rat brain. The greatest amounts of activity were found in the bed nucleus (n.) of the stria terminalis (700 protein fmol/h . mg) and in the medial (MA) and cortical amygdala (400-600 fmol/h . mg protein) of the male. There was an evident rostral-caudal and medial-lateral gradient in AA throughout the diencephalon. Activity was high in the periventricular preoptic n. and medial preoptic n.; intermediate in the suprachiasmatic preoptic n., anterior hypothalamus, periventricular anterior hypothalamus, and ventromedial n.; and low in the arcuate n.-median eminence, lateral preoptic n., supraoptic n., dorsomedial n., and lateral hypothalamus. Regions devoid of measurable AA included the medial and lateral septum, caudate-putamen, hippocampus, and parietal cortex. In the female, AA was greatest in the MA and cortical amygdala. We found that AA in the MA, stria terminalis n., suprachiasmatic preoptic n., periventricular preoptic in., medial preoptic n., anterior hypothalamus, and ventromedial n. was significantly greater (P less than 0.05) in males than in females. Orchidectomy reduced AA to levels seen in females, and administration of testosterone to castrated males restored AA in these areas. No significant sex differences were observed in any other hypothalamic or amygdaloid nuclei, although AA was increased by testosterone treatment in the periventricular anterior hypothalamus, arcuate n.-median eminence, and lateral hypothalamus. Our results provide a quantitative profile of AA in specific hypothalamic and limbic nuclei of the rat brain as well as information on the control of AA within these discrete regions.
大鼠脑内雄激素向雌激素的转化由芳香化酶催化。这些酶的最高浓度出现在下丘脑和杏仁核内，它们似乎在雄激素影响行为和神经内分泌功能的过程中发挥重要作用。在本研究中，我们测量了成年大鼠脑内20个核团和脑区的芳香化酶活性（AA）水平。从600微米厚的冰冻切片中显微解剖出各个核团。将3只动物的组织合并，通过体外放射测定法测量AA，该方法通过量化[1β-3H]雄烯二酮立体特异性生成3H2O的量来作为雌激素形成的指标。我们报告AA在大鼠脑内呈异质性分布。活性最高的部位是终纹床核（700蛋白飞摩尔/小时·毫克）以及雄性大鼠的内侧杏仁核和皮质杏仁核（400 - 600飞摩尔/小时·毫克蛋白）。在整个间脑，AA存在明显的前后和内外梯度。在室周视前核和内侧视前核活性较高；在视交叉上视前核、下丘脑前部、室周下丘脑前部和腹内侧核活性中等；在弓状核 - 正中隆起、外侧视前核、视上核、背内侧核和外侧下丘脑活性较低。没有可测量AA的区域包括内侧和外侧隔区、尾状核 - 壳核、海马和顶叶皮质。在雌性大鼠中，AA在内侧杏仁核和皮质杏仁核中最高。我们发现，雄性大鼠内侧杏仁核、终纹床核、视交叉上视前核、室周视前核、内侧视前核、下丘脑前部和腹内侧核中的AA显著高于雌性（P < 0.05）。去势使AA降至雌性大鼠的水平，给去势雄性大鼠注射睾酮可使这些区域的AA恢复。在任何其他下丘脑或杏仁核核团中未观察到显著的性别差异，尽管睾酮处理使室周下丘脑前部、弓状核 - 正中隆起和外侧下丘脑的AA增加。我们的结果提供了大鼠脑内特定下丘脑和边缘核团中AA的定量概况以及这些离散区域内AA调控的相关信息。
