Binding of (3H)R5020 to progesterone receptor and serum contaminants in human endometrium

The binding of [3H]R5020 to cytosol from human endometrium was utilized to evaluate the concentration of progesterone receptor by means of agar gel electrophoresis, using D-norgestrel as cold competitor. It was observed that radioligand binds predominantly to the receptor, and that serum contaminants such as albumin and corticosteroid-binding globulin do not interfere in the assay procedure.