大鼠睾丸组织中的一种细胞质雌激素受体。

Endocrinology. 1976 Aug;99(2):555-66. doi: 10.1210/endo-99-2-555.

Testicular cytosol from Sprague-Dawley rats was shown to possess an estradiol binding component which exhibited the properties of a receptor. Specific binding of estradiol by the receptor was shown, at 4C in vitro, to reach equilibrium by 6 h. That level of binding was maintained at a plateau for 18 h. Estradiol binding was demonstrated to increase linearly as a function of testicular cytosol concentration ultilized. The Ka at equilibrium was determined as 4.07 .05 x 1010M-1, while the number of binding sites for whole testicular tissue from mature rats was 1.16 x 10-14 +/- 0.061 moles/mg cytosol protein. Sucrose gradient sedimentation analysis of the cytosol receptor revealed that the major peak of radioactivity migrated in the 8S region. Enzymatic treatment of the cytosol demonstrated that the binding component was protein in nature. Heat treatment, 70 C for 10 min, resulted in 83% loss of the receptor activity. Storage in liquid N2 (for as long as 60 days) was shown to maintain receptor activity. Steroid specificity studies revealed that other estrogens were competitive with 17beta-estradiol for binding sites, but progestins, testosterone, and dihydrotestosterone did not affect estradiol binding. Tissue specificity studies showed that the capacity of testicular cytosol to bind estradiol was much greater than that of several non-target organs. Ontogenically, the cytoplasmic estradiol-binding capacity/testis was low from 7 to 21 days of age, but rose dramatically between 3 and 7 weeks of age, and an apparent plateau was reached at 15 weeks. The injection of unlabeled 17beta-estradiolin vvio was shown to deplete the cytosol of estradiol binding sites as determined in vitro. Depletion was rapid, occurring within 30 min, and the cytoplasmic estradiol receptors remained low for a period of 4 h. At 6 h, replenishment has occurred and control levels of cytoplasmic receptors were restored by 12 h. These results suggest that an estradiol receptor is present in testicular tissue of the rat, and that binding capacity is maximum in the mature testis.

已证明，来自斯普拉格-道利大鼠的睾丸胞质溶胶具有一种雌二醇结合成分，该成分表现出受体的特性。在体外4℃条件下，受体对雌二醇的特异性结合在6小时时达到平衡。该结合水平在18小时内保持稳定。结果表明，随着所用睾丸胞质溶胶浓度的增加，雌二醇结合呈线性增加。平衡时的解离常数（Ka）测定为4.07±0.05×10¹⁰M⁻¹，而成熟大鼠整个睾丸组织的结合位点数为1.16×10⁻¹⁴±0.061摩尔/毫克胞质溶胶蛋白。对胞质溶胶受体进行蔗糖梯度沉降分析表明，放射性的主要峰在8S区域迁移。对胞质溶胶进行酶处理表明，结合成分本质上是蛋白质。70℃加热10分钟导致受体活性丧失83%。在液氮中储存（长达60天）可保持受体活性。类固醇特异性研究表明，其他雌激素与17β-雌二醇竞争结合位点，但孕激素、睾酮和双氢睾酮不影响雌二醇结合。组织特异性研究表明，睾丸胞质溶胶结合雌二醇的能力远大于几个非靶器官。从个体发育来看，7至21日龄时睾丸胞质溶胶中雌二醇结合能力较低，但在3至7周龄时急剧上升，并在15周时达到明显的平台期。在体内注射未标记的17β-雌二醇后，体外测定显示，睾丸胞质溶胶中的雌二醇结合位点被耗尽。耗尽迅速，在30分钟内发生，并且胞质溶胶中的雌二醇受体在4小时内保持较低水平。6小时时开始补充，12小时时胞质溶胶受体恢复到对照水平。这些结果表明，大鼠睾丸组织中存在雌二醇受体，且结合能力在成熟睾丸中最大。