The influence of the progestogen gestonorone caproate on testosterone turnover in renal cell carcinoma. An in vitro study.

To investigate the effect of gestagens on renal cell carcinoma 300-mg slices of normal, human kidney, renal cell carcinoma (RCC), and preoperatively irradiated RCC were subjected to a short term incubation with 200 pmoles of 3H-testosterone and 1 and 2 mug of gestonorone caproate. In the normal kidney 61.4 per cent of the testosterone added was metabolized, the oxidation products androstenedione and epitestosterone outweighing by 6:1 the reduction products 5alpha-dihydrotestosterone and androstanediol. In RCC only 22 per cent of the testosterone was metabolized, with 8.5 per cent being converted to 5alpha-androstanes. Gestonorone caproate essentially did not influence testosterone turnover. This can be explained by its action as an inhibitor of the reductive pathway of the testosterone metabolism only, which is insignificant in these tissues.