Quantitation of oestrogen receptors: use of solid-phase antisteroid antibodies to quantify binding sites and determination of dissociation constant.

The dextran-coated charcoal assay method of McGuire and DeLaGarza is a well-known method for quantitation of oestrogen receptors in breast tumour tissues. Castañeda and Liao reported that the solid-phase antisteroid antibodies are superior to dextran-coated charcoal for quantitating the receptor bound steroids. In this report we compare the results obtained using both methods to quantitate oestrogen receptors and determine the affinity for steroid binding in seven human breast tumours and the uteri of rat and calf.