Competitive protein binding assay of oestradiol-17 beta and oestrone using uterine cytosol prepared from HCG-treated rabbits.

Uterine cytosol was prepared from rabbits after treatment with human chorionic gonadotrophin (HCG) and used for the determination of oestradiol-17 beta and oestrone by competitive protein binding (CPB) assay. The so obtained uterine cytosol gave higher percentage of binding and proved to be more stable when stored at --20 degrees C than cytosol obtained from the pregnant uterus.