PROSTATE CONCENTRATIONS OF ENDOGENOUS ANDROGENS BY RADIOIMMUNOASSAY

A method for simultaneously determining concentration of major androgens in prostate was developed. Extraction techniques used to isolate the androgens from minced tissue include homogenization with high-speed blades in Delsal''s solvent mixture, adsorption to silica gel, followed by column and 1 TLC. Radioimmunoassays (RIA) of small aliquots of TLC eluates are used to quantitate picogram amounts of 5.alpha.-dihydrotestosterone (DHT) and 5.alpha.-androstanediols (Diol) and to estimate testosterone (T) and androstenedione (Ad). Contamination of blanks was reduced to RIA sensitivity limits primarily by treatment of glassware in a self-cleaning oven. The specificity of the method for each androgen was established by TLC separations of known prostate metabolites, antisera specificities and parallelism of sample aliquots to androgen RIA standards. The overall precision, in terms of coefficient of variation was 21% for DHT and 24% for Diol. T and Ad could not be measured with acceptable precision, because their very low concentration in prostate (.ltoreq. 0.5 ng/g tissue) were less than RIA sensitivity limits. Accuracy studies indicated recoveries ranging from 96% for Diol to 121% for DHT. In human benign hypertrophic prostate tissue, DHT averaged 153 ng/g soluble protein (5.8 ng/g tissue) which was 17 times higher than values obtained in human spleen and kidney; Diol in prostate showed no consistent differences from values noted in kidney of spleen.