ROLE OF DEHYDROEPIANDROSTERONE AND ITS SULPHATE IN SYNTHESIS OF TESTOSTERONE BY HUMAN TESTES IN VIVO AND IN VITRO

Abstract

The synthesis of testosterone from [4-¹⁴C]dehydroepiandrosterone (DHEA) and [7α-³H]dehydroepiandrosterone sulphate (DHEA-S) by human testes in vivo and in vitro was investigated. Neither free testosterone nor free DHEA was found in a perfused testis or the spermatic venous plasma after the infusion of [7α-³H]DHEA-S into the spermatic artery in vivo, whereas ³H-labelled free DHEA, testosterone and androstenedione were isolated after incubation of testicular tissue with the same substrate in vitro. Only ¹⁴C-labelled testosterone was found in the spermatic venous effluent and in the testis after infusion of a mixture of equimolar amounts of [7α-³H]-DHEA-S and [4-¹⁴C]DHEA into the spermatic artery in vivo. Testosterone containing ³H and ¹⁴C was isolated after incubation of testicular tissue with a mixture of the two substrates in vitro.