MacLusky N J, Clark C R, Shanabrough M, Naftolin F
Department of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, CT 06510.
Brain Res. 1987 Sep 29;422(1):83-91. doi: 10.1016/0006-8993(87)90542-7.
The binding of [3H]androgens and estrogens, and the metabolism of [3H]androgens, were studied in the spinal cord of the adult rat. High-affinity, specific binding sites for [3H]testosterone and [3H]estradiol were detected in cytosol fractions from the spinal cords of castrate animals. Equilibrium dissociation constants for reaction of these sites with their respective ligands were similar to those of androgen and estrogen receptors from other regions of the central nervous system. Nuclear binding of [3H]estradiol was observed in the spinal cord 1 h after intravenous administration of the isotope. Likewise, exchange assay demonstrated the presence of high-affinity androgen binding sites in spinal cord nuclei from orchidectomized, testosterone propionate treated animals. 5 alpha-Reductase activity in homogenates of the spinal cord was relatively high, approximately 3 times that in the pooled hypothalamus, preoptic area, septum and amygdala. However, in contrast to the latter brain regions, estrogen formation was not detectable in spinal cord tissue. No sex differences were observed in the metabolism of [3H]testosterone by spinal cord homogenates. These results confirm the presence of androgen and estrogen receptors in the rat spinal cord. The lack of detectable aromatase activity in the spinal cord is consistent with the hypothesis that the effects of circulating testosterone on spinal reflex function are mediated primarily through the androgen receptor system.
研究了成年大鼠脊髓中[3H]雄激素和雌激素的结合以及[3H]雄激素的代谢。在去势动物脊髓的胞质溶胶组分中检测到了[3H]睾酮和[3H]雌二醇的高亲和力、特异性结合位点。这些位点与其各自配体反应的平衡解离常数与中枢神经系统其他区域的雄激素和雌激素受体相似。静脉注射同位素1小时后，在脊髓中观察到了[3H]雌二醇的核结合。同样，交换分析表明，在经丙酸睾酮处理的去势动物的脊髓核中存在高亲和力雄激素结合位点。脊髓匀浆中的5α-还原酶活性相对较高，约为下丘脑、视前区、隔区和杏仁核合并组织中活性的3倍。然而，与后几个脑区不同，在脊髓组织中未检测到雌激素的生成。脊髓匀浆对[3H]睾酮的代谢未观察到性别差异。这些结果证实了大鼠脊髓中存在雄激素和雌激素受体。脊髓中未检测到芳香化酶活性，这与循环睾酮对脊髓反射功能的影响主要通过雄激素受体系统介导的假说一致。
