Iwashita M, Catt K J
Endocrinology. 1985 Aug;117(2):738-46. doi: 10.1210/endo-117-2-738.
A radioactive photoaffinity label for the GnRH receptor was prepared by derivatization of radiodinated [D-Lys6] des-Gly10-GnRH N-ethylamide with the heterobifunctional photolabile reagent N-hydroxysuccinimidyl-4-azido-benzoate. This high affinity photoreactive analog was employed for radiolabeling and characterization of pituitary GnRH receptors in rat, rabbit, mouse, sheep, and cow adenohypophyses and gonadal GnRH receptors in the rat ovary and testis. In rat, rabbit, and mouse pituitary glands, analysis of the GnRH receptor-ligand complex by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography showed two labeled components, both of which were displaced by unlabeled GnRH agonist and antagonist analogs. The larger receptor component was a relatively broad band, with mol wt in rat, rabbit, and mouse of 59,000 +/- 1,900, 62,000 +/- 700, and 60,000 +/- 800, respectively. In the rat pituitary gland, the larger component was composed of 63,000 and 52,000 mol wt components, of which the latter was more heavily labeled and was predominant in purified pituitary gonadotrophs. The mol wts of the smaller components were 40,000 +/- 1,600, 43,000 +/- 1,200, and 41,000 +/- 1,000, respectively. In bovine and ovine pituitary glands, the photolabeled GnRH receptor was a single band with mol wt of 42,000 +/- 1,200 and 39,000 +/- 500, respectively. In the rat ovary and testis, photolabeled GnRH receptors were similar to those in the rat pituitary gland, with two distinct components of 53,000 +/- 1,000 and 42,000 +/- 1,000 mol wt. These findings demonstrate that the pituitary receptors that mediate similar physiological actions of GnRH in different species possess broadly similar structural properties, with minor variations between species. It is also evident that the divergent actions of GnRH in different tissues of the same species, as in the rat pituitary and gonads, are expressed through receptors of similar structure.
通过用异双功能光不稳定试剂N - 羟基琥珀酰亚胺 - 4 - 叠氮基苯甲酸对放射性碘化的[D - Lys6]去 - Gly10 - GnRH N - 乙基酰胺进行衍生化，制备了一种用于促性腺激素释放激素（GnRH）受体的放射性光亲和标记物。这种高亲和力的光反应性类似物用于大鼠、兔、小鼠、绵羊和牛腺垂体中垂体GnRH受体的放射性标记和表征，以及大鼠卵巢和睾丸中性腺GnRH受体的放射性标记和表征。在大鼠、兔和小鼠的垂体中，通过十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳和放射自显影分析GnRH受体 - 配体复合物，显示出两个标记成分，这两个成分都能被未标记的GnRH激动剂和拮抗剂类似物所取代。较大的受体成分是一条相对较宽的带，在大鼠、兔和小鼠中的分子量分别为59,000±1,900、62,000±700和60,000±800。在大鼠垂体中，较大的成分由分子量为63,000和52,000的成分组成，其中后者标记更重，并且在纯化的垂体促性腺激素细胞中占主导地位。较小成分的分子量分别为40,000±1,600、43,000±1,200和41,000±1,000。在牛和羊的垂体中，光标记的GnRH受体是一条单一的带，分子量分别为42,000±1,200和39,000±500。在大鼠卵巢和睾丸中，光标记的GnRH受体与大鼠垂体中的相似，有两个不同的成分，分子量分别为53,000±1,000和42,000±1,000。这些发现表明，在不同物种中介导GnRH相似生理作用的垂体受体具有广泛相似的结构特性，物种之间存在微小差异。同样明显的是，在同一物种的不同组织中，如大鼠垂体和性腺中，GnRH的不同作用是通过结构相似的受体来表达的。
