The Radioimmunoassay of Testosterone, 5α‐Dihydrotestosterone and Their Precursors in the Human Testis

A method is described for the simultaneous radioimmunoassays of pregnenolone, progesterone, 17α‐hydroxyprogesterone, androstenedione, testosterone and 5α‐dihydrotestosterone in 100 mg samples of human testis tissue. The specificity is illustrated by determining the chromatographic elution profiles of steroid extracts by radioimmunoassay. The C.V. of individual assays were assessed by analysing 5 samples taken from the same testis, and illustrates the high reproducibility of the method, and homogeneity of samples. The stability of endogenous testicular steroids was assessed in relation to time at room temperature, and marked changes in composition occurred within 5 h, indicating the limitations in using autopsy samples. Testicular steroid concentrations were determined in testes from 16 patients, 10 of whom had been treated with estrogen (polyestradiol phosphate) 1–5 days before orchiectomy. No effect of estrogen treatment on testicular concentrations of steroids was observed, despite the previously established decline in levels of these steroids in the spermatic veins of similar patients.