Towards a reproducible method of estimating androgen receptors in human prostate.

The effect of sodium molybdate and the stability of [3H]-R1881 on the reproducibility of androgen receptor assays in the human prostate gland have been investigated. The drying down of radio-labelled methyltrienolone, prior to incubation with cytosolic and nuclear extracts, resulted in a marked disintegration of the compound and a loss of specific binding of up to 40%. By contrast, the inclusion of sodium molybdate in the homogenisation buffer significantly increased the specific nuclear and cytosolic binding. In the cytosol, this increase was directly proportional to the amount of molybdate added up to 50 mM whereas in the nucleus binding was maximal at a molybdate concentration of 10 mM and declined at higher concentrations.