A demonstration of androgen and estrogen receptors in a human breast cancer using a new protamine sulfate assay.

Separate receptors for estrogen and androgen are demonstrated in cells from metastic human breast cancer. By criteria of binding affinity, number of binding sites, and specificity of the receptor for different steroids, the receptors are shown to be distinguishable. The protamine sulfate receptor assay technique employed allows both kinds of receptor to be quantified conveniently and reproducibly without interference by plasma steroid-binding components.