Ohno Ken-ichi, Suzuki Sachiko, Fukushima Takeshi, Maeda Masako, Santa Tomofumi, Imai Kazuhiro
Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Analyst. 2003 Aug;128(8):1091-6. doi: 10.1039/b303985d.
In this study, we examined the affinities of many (21) compounds such as hormones, pharmaceuticals, industrial chemicals, and phytoestrogens to the estrogen receptor (ER) by ER binding assay using fluorescence polarization (FP). This method is based on the competitive binding assay using fluorescein-labeled estradiol (F-E2), in which the polarization values decreased with the addition of the compounds (competitors). The obtained sigmoidal inhibition curves were transformed into the pseudo-Hill plots, and the concentrations at 50% inhibition (IC50) and Hill coefficients were obtained from the regression equations. We examined the relationship between the chemical structures and estrogenic activities, and finally classified the tested compounds into three categories, agonists, partial agonists and antagonists based on their Hill coefficients.
