摘要
Pituitary cytosot was prepared from adult spayed Sprague-Dawtey female rats, primed by estradiol benzoate for 6 days. the progestin receptor binding activity of the pituitary cytosol was determined by hydroxylapatite adsorption of the bound steroid-receptor complex with tritiated R5020 as ligund. Seatchard analysis of saturation curve showed that the dissociation constant (Kd) of the bound progestin(P) receptor ligand complex was 1.8nM and the greatest binding site was 138 fmoles/mg protein. RU486 could competitively inhibB the binding of ^3H-R5020 to pituitary cytosol progestin receptor.The competitve ability of the untabelled RU486, R5020 or progesterone with ^3H-R5020 are essentially the same.
