Methods for the determination of androgen receptor content in human prostatic tissue

Human prostatic androgen receptor content can be measured reliably in either fresh or bulk tissue stored in liquid nitrogen using (3H) R 1881 at incubation conditions of 4 C for 20 hr. Powdered tissue stored in liquid nitrogen for more than 12 days shows a marked deterioration in receptor content. Although multiple point dextran coated charcoal assays analyzed by Scatchard plot are preferable for receptor quantitation of bulk tissue, the single saturating dose assay provides useful information on needle biopsy specimens. When this technique is used to evaluate samples with protein concentrations less than 1 mg per ml, the use of hydroxylapatite to separate receptor bound and free steroid is superior to the use of dextran coated charcoal. The addition of sodium molybdate to the homogenization buffers results in a marked increase in cystosolic androgen receptor content and a decrease in extractable nuclear receptor content. The use of a vertical rotor to ensure short centrifugation times enhances the reliability of sucrose density gradient analyses of human prostatic androgen receptor.