Horwitz K B, McGuire W L
Steroids. 1975 Apr;25(4):497-505. doi: 10.1016/0039-128x(75)90027-6.
We have identified a specific progesterone receptor in 11 of 33 human breast cancer cytosols. Since progesterone itself binds to glucocorticoid receptor, to corticosteroid binding globulin (CBG), and to nonspecific components as well as to its own receptor, we have used a synthetic progestin, R5020 (17,21-dimethyl-19-nor-4,9-pregnadiene-3,20-dione), whose binding specificity is restricted to progesterone receptor. Bound R5020 sediments at 8 S in sucrose gradients; binding is competed by excess unlabeled R5020 or progesterone. The receptor is distinct from glucocorticoid receptor and CBG as determined by competition studies using dexamethasone and hydrocortisone. The dissociation constant for R5020 obtained by Scatchard analysis of dextran-coated charcoal assays is approximately 2 times 10- minus 9 M.
我们在33份人乳腺癌胞液中的11份中鉴定出了一种特定的孕激素受体。由于孕激素本身会与糖皮质激素受体、皮质类固醇结合球蛋白（CBG）、非特异性成分以及其自身受体结合，我们使用了一种合成孕激素R5020（17,21-二甲基-19-去甲-4,9-孕二烯-3,20-二酮），其结合特异性仅限于孕激素受体。结合的R5020在蔗糖梯度中以8S沉降；结合可被过量未标记的R5020或孕激素竞争。通过使用地塞米松和氢化可的松的竞争研究确定，该受体与糖皮质激素受体和CBG不同。通过葡聚糖包被活性炭分析的Scatchard分析获得的R5020解离常数约为2×10⁻⁹ M。
