Orti E, Magariños A M, De Nicola A F
Neuroendocrinology. 1986;43(3):404-9. doi: 10.1159/000124556.
Cytosol from the spinal cord (SC) of adrenalectomized rats was incubated with a range of [3H]-aldosterone (ALDO) concentrations and the results analyzed according to Scatchard. High affinity (Kd less than or equal to 1 nM) as well as low affinity (Kd 30-195 nM) sites were measured; the low affinity site was abolished by co-incubation with the pure antiglucocorticoid RU 28362. [3H]-ALDO in concentrations shown to bind to the high affinity site only, was completely displaced by the spirolactone, RU 26752, but not by RU 28362; however, the latter compound competed for 40% of the sites when incubated with a higher (10 nM) concentration of [3H]-ALDO, binding approximately one-half to each receptor type. The high affinity site was distributed uniformly in four sections of the SC, with significantly lower levels in the region corresponding to the filum terminale and horse tail and slightly higher in the cervical and lumbar enlargements. The high affinity site acquired increased affinity for DNA-cellulose after heat-induced transformation, with reduced capacity to bind to DEAE-cellulose. These results suggest that the SC contains, in addition to glucocorticoid receptors, binding molecules of high affinity and stereoselectivity for mineralocorticoids, and that, under appropriate conditions, present increased affinity for DNA acceptor sites.
将去肾上腺大鼠脊髓（SC）的胞质溶胶与一系列[3H] -醛固酮（ALDO）浓度进行孵育，并根据Scatchard法分析结果。测量到了高亲和力（Kd≤1 nM）以及低亲和力（Kd 30 - 195 nM）位点；低亲和力位点在与纯抗糖皮质激素RU 28362共同孵育时被消除。仅与高亲和力位点结合的[3H] - ALDO浓度完全被螺内酯RU 26752取代，但不被RU 28362取代；然而，当与较高（10 nM）浓度的[3H] - ALDO孵育时，后一种化合物竞争40%的位点，大约一半与每种受体类型结合。高亲和力位点在脊髓的四个节段中分布均匀，在终丝和马尾对应的区域水平显著较低，在颈膨大及腰膨大处略高。热诱导转化后，高亲和力位点对DNA -纤维素的亲和力增加，而与DEAE -纤维素结合的能力降低。这些结果表明，脊髓除了含有糖皮质激素受体外，还含有对盐皮质激素具有高亲和力和立体选择性的结合分子，并且在适当条件下，对DNA受体位点具有增加的亲和力。
