In Vitro Uptake of3H Testosterone and its Conversion to Dihydrotestosterone by Prostatic Carcinoma and Other Tissues

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Abstract
Needle biopsies of normal, benign hyperplastic, neoplastic and metastatic prostatic tissues were used to study the uptake of 3H-testosterone by these tissues and their ability to convert testosterone to dihydrotestosterone. Histological quantification is important because stroma is active in both these areas of biochemical activity. 3H-Testosterone uptake by the tissues is relatively similar but benign prostatic hyperplasia and normal tissue consistently convert more testosterone to dihydrotestosterone than neoplastic tissues. The least active in this regard are pure biopsies of neoplastic cells obtained from nodal metastases, suggesting extensive loss or repression of 5-.alpha.-reductase activity. This defect is present in neoplastic tissues even if the patient has had an orchiectomy and/or received hormonal therapy. It is not known whether testosterone may substitute for dihydrotestosterone in the neoplastic nucleus. Animal models that yield data on suppression of 5-.alpha.-reductase activity by certain agents may have limited relevance to the tissues of human prostatic carcinoma.