Luzzani F, Glässer A
Biochem Pharmacol. 1984 Jul 15;33(14):2277-81. doi: 10.1016/0006-2952(84)90667-1.
The binding of [3H]spironolactone to kidney homogenates from adrenalectomized rats was studied by dextran-charcoal absorption methods. [3H]Spironolactone binds with high affinity and low capacity (KD = 12.9 +/- 0.6 nM; Bmax = 93.4 +/- 3.8 fmoles/mg protein) at low temperatures (0 degrees-2 degrees). Its hormone specificity, as measured by relative binding affinity (RBA) is spironolactone greater than prorenone greater than methyltrienolone greater than testosterone greater than progesterone greater than aldosterone greater than dexamethasone. In the same tissue preparation, specific spironolactone binding sites and classical mineralocorticoid receptor sites labelled with [3H]aldosterone differ in their thermal stability, binding parameters and hormone specificities, whereas their tissue distributions are similar. In conclusion, [3H]spironolactone binds specifically to kidney homogenates from adrenalectomized rats and these binding sites, apparently, are different from the classical mineralocorticoid receptors. The theoretical and practical aspects of this finding are discussed.
采用葡聚糖-活性炭吸附法研究了[3H]螺内酯与肾上腺切除大鼠肾脏匀浆的结合情况。在低温（0℃-2℃）下，[3H]螺内酯以高亲和力和低容量结合（KD = 12.9±0.6 nM；Bmax = 93.4±3.8 fmol/mg蛋白）。通过相对结合亲和力（RBA）测定，其激素特异性为螺内酯＞孕烯诺酮＞甲基三烯醇酮＞睾酮＞孕酮＞醛固酮＞地塞米松。在同一组织制剂中，用[3H]醛固酮标记的特异性螺内酯结合位点和经典盐皮质激素受体位点在热稳定性、结合参数和激素特异性方面存在差异，但其组织分布相似。总之，[3H]螺内酯与肾上腺切除大鼠的肾脏匀浆特异性结合，这些结合位点显然不同于经典的盐皮质激素受体。讨论了这一发现的理论和实际意义。
