Hormonal consequences of orchidectomy for carcinoma of the prostate. With special reference to the measurement of free testosterone in saliva and prostatic dihydrotestosterone levels.

22 patients with metastatic carcinoma of the prostate were treated by subcapsular orchidectomy and followed by regular determinations of plasma testosterone, dihydrotestosterone, delta 4-androstenedione, dehydroepiandrosterone sulfate and testosterone estradiol-binding globulin as well as salivary testosterone, which reflects free plasma testosterone. Subcapsular orchidectomy constantly induced a dramatic and stable decrease in testicular androgens without modification of adrenal androgens or testosterone estradiol-binding globulin. Free testosterone levels vary widely for a given value of plasma testosterone, probably due to individual variations of testosterone estradiol-binding globulin. Salivary testosterone is preferable to plasma testosterone for monitoring hormonal therapy for metastatic carcinoma of the prostate. In another group of orchidectomized stage-D2 patients, obstructive symptoms motivated transurethral resection of the prostate allowing the assay of intraprostatic dihydrotestosterone which was constantly below the dihydrotestosterone level of androgen-independent tissues (below 2.5 ng/g).