Hormonally responsive areas of the reproductive system of the male guinea pig. III. Presence of cytoplasmic estrogen receptors.
Hormonally responsive areas of the reproductive system of the male guinea pig. III. Presence of cytoplasmic estrogen receptors.
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雄性豚鼠生殖系统的激素反应区域。
DOI：
10.1095/biolreprod25.5.1159
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发表时间：
1981
影响因子：
3.6
通讯作者：
Davies,J
中科院分区：
文献类型：
--
作者：
Danzo,BJ;StRaymond,PA;Davies,J
我们之前的研究表明，给成年雄性豚鼠注射雌激素会导致其附属性器官（精囊、前列腺、射精腔、凝乳腺和附睾）的各种形态变化。为了确定雌激素对这些组织的直接作用是否存在生化基础，我们检查了它们是否存在雌激素受体。我们确定从副性腺制备的细胞质含有雌二醇-17β的大分子结合成分。在低（0.01 M KCl）离子强度条件下，该组分在5-20%蔗糖梯度下以8S种沉积，在高（0.4 M KCl）离子强度条件下以4S种沉积。时间过程研究表明，在2 h内达到结合平衡；[3H]雌二醇与结合蛋白的解离非常缓慢（1½bb0 - 42 h）。细胞质结合剂对雌激素具有高度特异性；各种雌激素对该蛋白的相对亲和力分别为雌二醇= 1，雌二醇= 0.72，己烯雌酚0.30，雌三醇= 0.17。孕酮、睾酮和5α-二氢睾酮即使过量1000倍，对[3H]雌二醇与蛋白质结合的抑制作用也不到10%。从附属性器官（附睾除外）制备的细胞质中存在的结合剂，其平衡解离常数为0.7 nM，每mg细胞质蛋白有30个结合位点。细胞质雌激素结合剂表现出通常归因于受体的特征，与存在于血浆中的非特异性、快速解离的4S结合剂明显不同。在类固醇特异性的基础上，细胞质雌激素结合剂不同于存在于男性生殖组织中的雄激素受体。
We have previously shown that the administration of estrogens to intact adult male guinea pigs resulted in a variety of morphological changes in their accessory sex organs (the seminal vesicles, prostate, common ejaculatory chamber, coagulating gland, and epididymis). To ascertain if a biochemical basis existed for a direct action of estrogens on these tissues, we examined them for the presence of estrogen receptors. We determined that cytosol prepared from the accessory sex glands contains a macromolecular binding component for estradiol-17β. This component sediments as an 8S species on 5–20% sucrose gradients under low (0.01 M KCl) ionic strength conditions and as a 4S species under high (0.4 M KCl) ionic strength conditions. Time-course studies indicate that binding equilibrium is achieved in ∿2 h; dissociation of [3H] estradiol from the binding protein is very slow (t½>42 h). The cytoplasmic binder is highly specific for estrogens; the relative affinities of various estrogens for the protein were estradiol = 1, estrone = 0.72, diethylstilbestrol 0.30, and estriol = 0.17. Progesterone, testosterone, and 5α-dihydrotestosterone, even at a 1000-fold excess, caused less than 10% inhibition of [3H] estradiol binding to the protein. The binder present in cytosol prepared from the accessory sex organs (excluding the epididymis) exhibited an equilibrium dissociation constant of ∿0.3 nM, and there were ∿30 fmoles of binding sites per mg of cytosol protein. The cytoplasmic estrogen binder exhibits the characteristics usually attributed to receptors and is clearly different from a 4S, nonspecific, rapidly dissociating binder that is present in plasma. On the basis of steroid specificity, the cytoplasmic estrogen binder is distinct from the androgen receptor that is present in male reproductive tissues.