Yuh K C, Keyes P L
Endocrinology. 1979 Sep;105(3):690-6. doi: 10.1210/endo-105-3-690.
Nuclear and cytoplasmic estrogen receptors have been identified and characterized in the rabbit corpus luteum, and validated methods are described for the measurement of both unoccupied and total estrogen receptor. Binding was specific for the biologically active estrogens. Equilibrium binding analysis of cytoplasmic estrogen receptor yielded saturable, high affinity binding sites with a Kd of 5.4 x 10(-11) M. Two types of binding sites were found in the nuclear fraction: one with high affinity (Kd = 8.9 x 10(-11) M) and low capacity, the other with low affinity (Kd = 2.7 x 10(-8) M) and high capacity. In the presence of 0.4 M KCl, the sedimentation coefficients of nuclear and cytoplasmic estrogen receptors are 3.4S, while the value is 6.8S for cytoplasmic receptor in buffer without KCl. Twenty minutes after an iv injection of 2 micrograms 17 beta-estradiol, the available and total cytoplasmic estrogen receptors were depleted. This depletion was accompanied by concomitant and stoichiometric accumulation of receptor in the nucleus, indicating an apparent translocation of the receptor. In corpora lutea of normal rabbits, approximately 80% of the total nuclear receptor is unoccupied. Evidence is presented to suggest that nuclear receptor sites might be ordinarily occupied with estradiol, but during isolation of the nuclear fraction these sites become available or unoccupied. The identification of nuclear estrogen receptor and the phenomenon of translocation of cytoplasmic receptor to the nucleus suggest a similarity of estrogen action in the rabbit corpus luteum and other estrogen target tissues.
已在兔黄体中鉴定并表征了核雌激素受体和细胞质雌激素受体，并描述了用于测量未占据和总雌激素受体的经过验证的方法。结合对生物活性雌激素具有特异性。细胞质雌激素受体的平衡结合分析产生了可饱和的、高亲和力的结合位点，其解离常数（Kd）为5.4×10⁻¹¹M。在核部分中发现了两种类型的结合位点：一种具有高亲和力（Kd = 8.9×10⁻¹¹M）且容量低，另一种具有低亲和力（Kd = 2.7×10⁻⁸M）且容量高。在0.4M氯化钾存在下，核雌激素受体和细胞质雌激素受体的沉降系数为3.4S，而在无氯化钾的缓冲液中细胞质受体的值为6.8S。静脉注射2微克17β-雌二醇20分钟后，可用的和总的细胞质雌激素受体被耗尽。这种耗尽伴随着受体在核中的同时且化学计量的积累，表明受体发生了明显的易位。在正常兔的黄体中，约80%的总核受体未被占据。有证据表明，核受体位点通常可能被雌二醇占据，但在分离核部分期间，这些位点变得可用或未被占据。核雌激素受体的鉴定以及细胞质受体向核的易位现象表明，兔黄体和其他雌激素靶组织中雌激素作用具有相似性。
