Ortí E, Tornello S, De Nicola A F
J Neurochem. 1985 Dec;45(6):1699-707. doi: 10.1111/j.1471-4159.1985.tb10525.x.
In spite of biochemical and autoradiographic evidence for glucocorticoid binding sites in the spinal cord (SC), events occurring after the preliminary step of hormone binding were not studied. In this investigation, we have examined the transformation (activation) of the cytosolic receptor coupled to [3H]dexamethasone (DEX) and the in vivo interaction of adrenal hormone [corticosterone (CORT)] with purified nuclei from the SC, in addition to the CORT content of the SC before and after stress. Binding of [3H]DEX in the SC was 40% lower than in the hippocampus (HC), although the KD values were comparable. Transformation of [3H]DEX-receptor complexes in the cytosol was demonstrated by diethylaminoethane-cellulose chromatography, by DNA-cellulose binding, and by a combined minicolumn procedure including hydroxyapatite in addition to the last two techniques for separation of transformed, nontransformed, and meroreceptor complexes. In all these situations, SC glucocorticoid binding sites behaved similarly to those in the HC. Nuclear uptake of a tracer dose of [3H]CORT was much lower in the SC than in the HC; nuclear retention of CORT was more easily detected by radioimmunoassay after injection of 1 mg of CORT into adrenalectomized rats. Substantial amounts of CORT, which increased in level after stress, were measured in five regions in the SC, with higher concentrations in the cervical regions. These studies suggest that although SC and HC receptors show similar properties in vitro, differences emerged at the level of nuclear uptake in vivo, in that glucocorticoid action in the SC was similar to that in the optic nerve, where receptors seem to be localized mostly in glial cells.
尽管有生化和放射自显影证据表明脊髓（SC）中存在糖皮质激素结合位点，但激素结合初步步骤之后发生的事件尚未得到研究。在本研究中，我们除了检测应激前后脊髓中皮质酮（CORT）的含量外，还研究了与[3H]地塞米松（DEX）偶联的胞质受体的转化（激活）以及肾上腺激素[皮质酮（CORT）]与脊髓纯化细胞核的体内相互作用。脊髓中[3H]DEX的结合比海马体（HC）低40%，尽管解离常数（KD）值相当。通过二乙氨基乙烷 - 纤维素色谱法、DNA - 纤维素结合以及包括羟基磷灰石的联合微柱程序（除了用于分离转化、未转化和部分受体复合物的最后两种技术）证明了胞质中[3H]DEX - 受体复合物的转化。在所有这些情况下，脊髓糖皮质激素结合位点的行为与海马体中的相似。示踪剂量的[3H]CORT在脊髓中的核摄取比在海马体中低得多；在给肾上腺切除的大鼠注射1 mg CORT后，通过放射免疫测定更容易检测到CORT的核保留。在脊髓的五个区域测量到大量应激后水平升高的CORT，在颈部区域浓度更高。这些研究表明，尽管脊髓和海马体受体在体外表现出相似的特性，但在体内核摄取水平上出现了差异，因为脊髓中的糖皮质激素作用与视神经中的相似，在视神经中受体似乎主要定位于神经胶质细胞。
