THE INFLUENCE OF SERUM ON UPTAKE, CONVERSION AND ACTION OF TESTOSTERONE IN RAT PROSTATE GLANDS IN ORGAN CULTURE

Abstract

SUMMARY Explants of ventral rat prostates were incubated with [1,2-3H]testosterone in media (1) without serum, (2) with horse or calf serum, and (3) with human male or human pregnancy serum. With all sera the uptake of testosterone fell with rising serum content. At the same concentration, the uptake of testosterone and the amounts of dihydrotestosterone and androstanediol formed were significantly lower in explants incubated with pregnancy serum than in those incubated with male serum. Since testosterone binding is markedly higher in pregnancy than in male serum it was concluded that only the free unbound form of the hormone may be available to the target tissue. This was supported by findings that the degree of maintenance by testosterone in prostatic explants grown for 6 days without serum, or in the presence of either male or pregnancy serum, was closely related to the uptake and metabolism of testosterone under these three conditions. The results suggest that the degree of testosterone binding regulates the supply of hormone to the target organ and, thus, influences its biological action.