Urban J H, Miller M A, Dorsa D M
Geriatric Research, Education, and Clinical Center, Veterans Administration Medical Center, Seattle, Washington 98108.
Endocrinology. 1991 Jul;129(1):109-16. doi: 10.1210/endo-129-1-109.
Vasopressin (VP) neurons in the bed nucleus of the stria terminalis (BNST) and medial amygdala (AME) are sensitive to changes in circulating levels of testosterone (T). To determine whether these cells are responsive to changes in glucocorticoid levels, in situ hybridization and quantitative autoradiography were used to measure VP mRNA in cells of the BNST and AME in rats that were adrenalectomized (ADX; 14 days) or ADX with dexamethasone (DEX) replacement. These treatments produced the predicted changes in VP gene expression in the medial parvocellular group of the paraventricular nucleus. The VP mRNA content within cells of the BNST or AME was unaffected by adrenalectomy. Treatment with DEX significantly decreased both the number and labeling intensity of VP cells in the BNST and AME. Measurement of plasma T in these animals showed that DEX treatment significantly lowered mean T levels compared with those in either sham-operated or ADX animals. Adrenalectomy alone did not significantly alter T levels. To determine whether DEX influenced VP gene expression via a glucocorticoid action or secondarily by a suppression of T, the above experiment was repeated with groups that were castrated and implanted with Silastic capsules containing T to maintain physiological levels of T. Administration of DEX again decreased both VP cell number and labeling intensity of cells in the BNST and AME in sham-implanted animals. However, VP gene expression was unaffected in those animals that received T capsules. Administration of corticosterone did not alter T levels or the number of cells in the BNST or AME. These results suggest that, in contrast to paraventricular nucleus neurons, adrenalectomy (14 days) is not a potent stimulus in altering VP activity in the BNST or AME. The DEX-induced decrease in VP gene expression is mediated by a secondary suppression of T levels. These results support the finding that gonadal steroids are essential in maintaining the biosynthetic integrity of VP neurons in the BNST and AME.
终纹床核（BNST）和内侧杏仁核（AME）中的加压素（VP）神经元对循环睾酮（T）水平的变化敏感。为了确定这些细胞是否对糖皮质激素水平的变化有反应，采用原位杂交和定量放射自显影技术，测量肾上腺切除（ADX；14天）或肾上腺切除并用 dexamethasone（DEX）替代的大鼠BNST和AME细胞中的VP mRNA。这些处理在室旁核内侧小细胞群中产生了VP基因表达的预期变化。BNST或AME细胞内的VP mRNA含量不受肾上腺切除术的影响。DEX处理显著降低了BNST和AME中VP细胞的数量和标记强度。对这些动物血浆T的测量表明，与假手术或ADX动物相比，DEX处理显著降低了平均T水平。单独肾上腺切除术并未显著改变T水平。为了确定DEX是通过糖皮质激素作用还是通过抑制T间接影响VP基因表达，对去势并植入含T的硅胶胶囊以维持生理T水平的组重复上述实验。在假植入动物中，给予DEX再次降低了BNST和AME中VP细胞数量和细胞标记强度。然而，接受T胶囊的动物中VP基因表达未受影响。给予皮质酮未改变T水平或BNST或AME中的细胞数量。这些结果表明，与室旁核神经元不同，肾上腺切除（14天）不是改变BNST或AME中VP活性的有效刺激。DEX诱导的VP基因表达降低是由T水平的继发性抑制介导的。这些结果支持了性腺类固醇对于维持BNST和AME中VP神经元生物合成完整性至关重要的发现。
