The objectives of the proposed work are to quantitate and compare receptors for estrogens in cytosol and other subcellular fractions of human prostatic tissues and biopsies for the ultimate purpose of correlation of these estimates with the pathology of the prostate and the treatment and the clinical aspects of the patients with cancer of that organ. We shall also determine androgen and other hormone receptors, e.g. for progesterone, because it is essential to obtain an overall picture of receptor quantitation in any one particular sample. We propose to study 50-100 samples and correlate the receptor determinations with therapeutic and clinical parameters in a concerted effort to use this correlation is a manner analogous to breast cancer. Our source of tissue will be urological centers affiliated with the National Prostatic Cancer Project as well as our own Institute and hospitals in the immediate area. Tissue can be in the form of gram quantity from prostatectomy for BPH and cancer, or from needle biopsy of the prostate, and depending on the amount of tissue we shall determine specific receptors in multi-point Scatchard or double reciprocal plots or single point determinations. The former determinations supply data on number of binding sites and binding constants, while the latter give a positive or negative answer to the question of presence of receptors. DES, cyproterone acetate and R-5020 will be used as inhibitors for estrogen, androgen and progesterone receptors, respectively. In addition, we plan to develop zinc binders in the prostate as an adjunct in determining the hormonal status of that organ in relation to the pathological status.