Poortman J, Vroegindewey-Jie D, Thijssen J H, Schwarz F
Mol Cell Endocrinol. 1977 Jul;8(1):27-34. doi: 10.1016/0303-7207(77)90015-6.
The relative binding affinity of several androstane- and C-19-nor-androstane-compounds for the estradiol (E2)-receptor in human myometrial and mammary cancer tissue was studied. High speed cytosol was incubated with tritiated E2 alone as well as in the presence of increasing amounts of the compound to be tested. The highest affinity is found for steroids with two hydroxyl-groups at C-3 and C-17 in the beta-position and a double bond at C-4-5 or C-5-6. Saturation of the A-ring decreases the affinity: 5alpha-compounds have less affinity, 5-beta-compounds have less affinity; 5beta-compounds hardly any affinity. The presence of a hydroxyl-group in the 3alpha, 11beta or 16beta-position decreases the affinity, as dose a 3-oxo or 17-oxo-group. Removal of the C-19-methyl-group facilitates the binding. This data led to the concept that flatness of the A-ring in respect to the B-ring of the steroid molecule is a principal requirement for binding to the E2-receptor. The rank order of RBA is identical in myometrium and in mammary cancer tissue, indicating that estrogen-receptors are at least highly similar in both target tissues.
研究了几种雄甾烷和C-19-去甲雄甾烷化合物对人子宫肌层和乳腺癌组织中雌二醇（E2）受体的相对结合亲和力。高速胞质溶胶分别与氚标记的E2单独孵育，以及在存在逐渐增加量的待测试化合物的情况下孵育。发现对在β位的C-3和C-17处具有两个羟基基团且在C-4-5或C-5-6处具有双键的类固醇具有最高亲和力。A环的饱和会降低亲和力：5α-化合物亲和力较低，5β-化合物亲和力较低；5β-化合物几乎没有亲和力。在3α、11β或16β位存在羟基会降低亲和力，3-氧代或17-氧代基团也会降低亲和力。去除C-19-甲基基团有利于结合。这些数据引出了这样一个概念，即类固醇分子的A环比B环扁平是与E2受体结合的主要要求。子宫肌层和乳腺癌组织中相对结合亲和力（RBA）的排序相同，表明雌激素受体在这两种靶组织中至少高度相似。
