Studies on the biosynthesis of 16-dehydro steroids. The metabolism of [4-14C]pregnenolone by boar adrenal and testis tissue in vitro.

1. The metabolism of [4-(14)C]pregnenolone in vitro by boar adrenocortical and testis tissue has been studied. 2. Boar testis tissue formed three labelled Delta(16)-steroids, 5alpha-androst-16-en-3alpha-ol, 5alpha-androst-16-en-3beta-ol and androsta-4,16-dien-3-one. In adrenal tissue very much smaller yields of the same metabolites were obtained. 3. Both tissues produced labelled progesterone, androst-4-ene-3,17-dione and testosterone in varying quantities. The amount of progesterone was about 120 times greater in the adrenal tissue. In testis tissue dehydroepiandrosterone was found only in small quantity. 4. A pathway is suggested for the biosynthesis of Delta(16)-steroids from pregnenolone in boar testis tissue. The possibility that progesterone may be an intermediate is discussed.