In vitro bioconversion of progesterone-4-C14 to 17α-hydroxyprogesterone and androst-4-ene-3,17-dione in testicular tissue of Tribolodon hakonensis Günther

Abstract Minced testes of the Japanese dace, Tribolodon hakonensis Gunther, were incubated in vitro with progesterone-4-C 14 . At least eleven transformation products were isolated by paper chromatography, two of which were identified as 17α-hydroxyprogesterone and androst-4-ene-3,17-dione by their chromatographic behavior and chemical characteristics, as well as on the basis of repeated crystallizations of the substances. The results seem to indicate that there are present the enzymes which catalyze 17α-hydroxylation and side-chain cleavage of progesterone in testicular tissue of the fish. These transformation products suggest that the biochemical pathway from progesterone to androst-4-ene-3,17-dione through 17α-hydroxyprogesterone is the same in fish as it is in mammals.