Haukkamaa M
J Steroid Biochem. 1984 Feb;20(2):569-73. doi: 10.1016/0022-4731(84)90125-0.
Microsomal membranes sedimented at 40 000 g were prepared from human myometrium samples. The progesterone binding properties of microsomal suspensions were determined by incubating microsomes and [3H]progesterone at 4 degrees C. Dextran-coated charcoal was used for the separation of bound and free steroids. Membrane-associated progesterone binding sites of high affinity were identified in microsomes prepared from pregnant and nonpregnant uteri. The binding was saturable (Kd approximately 4 X 10(-9) M, concentration of binding sites 400-900 fmol/mg microsomal protein) and specific for natural progesterone. Of 21 steroids tested only 21-hydroxy-4-pregnene-3,20-dione, 17 alpha-hydroxyprogesterone and testosterone showed moderate competition against progesterone with relative affinities between 7.0-20.0% (R.A. of progesterone 100%). 5 alpha-Dihydroprogesterone and 5 alpha-dihydrotestosterone showed weak cross reaction (relative affinities 2.5 and 2.0%, respectively). Corticosteroids, estrogens and the 5 synthetic progestins tested showed only weak competition with relative affinities lower than 1.0%. These microsomal progesterone binding sites of high affinity and limited capacity resemble steroid hormone receptors but they are different from the soluble cytosolic progesterone receptor of human uterus in terms of steroid specificity. The physiological function of this microsomal progesterone receptor is unknown.
从人子宫肌层样本中制备了在40000g离心力下沉淀的微粒体膜。通过在4℃下孵育微粒体和[³H]孕酮来测定微粒体悬浮液的孕酮结合特性。用葡聚糖包被的活性炭分离结合态和游离态类固醇。在从妊娠和未妊娠子宫制备的微粒体中鉴定出了具有高亲和力的膜相关孕酮结合位点。该结合具有饱和性（解离常数Kd约为4×10⁻⁹M，结合位点浓度为400 - 900fmol/mg微粒体蛋白），且对天然孕酮具有特异性。在测试的21种类固醇中，只有21 - 羟基 - 4 - 孕烯 - 3,20 - 二酮、17α - 羟基孕酮和睾酮对孕酮表现出中等程度的竞争，相对亲和力在7.0 - 20.0%之间（孕酮的相对亲和力为100%）。5α - 双氢孕酮和5α - 双氢睾酮表现出较弱的交叉反应（相对亲和力分别为2.5%和2.0%）。所测试的皮质类固醇、雌激素和5种合成孕激素仅表现出较弱的竞争，相对亲和力低于1.0%。这些具有高亲和力和有限容量的微粒体孕酮结合位点类似于类固醇激素受体，但在类固醇特异性方面与人类子宫可溶性胞质孕酮受体不同。这种微粒体孕酮受体的生理功能尚不清楚。
