Formation of 5 beta- and 5 alpha-products as major C19-steroids from progesterone in vitro in immature golden hamster testes.

Testicular homogenates from 8- to 55-day-old golden hamsters were incubated with [3H]progesterone, [14C]-progesterone, [3H]5 beta-pregnane-3,20-dione, [14C]progesterone plus [3H]5 beta-pregnane-3,20-dione, and [14C]progesterone plus [3H]5 alpha-pregnane-3,20-dione and NADPH. After incubation, the radioactive products were separated and identified by column and paper chromatographies with derivative formation and recrystallization to constant specific activity. The major C21-17-hydroxysteroids and C19-steroids formed from progesterone by the testes of immature golden hamsters were 5 beta- and 5 alpha-steroids, such as 3 alpha,17-dihydroxy-5 beta-pregnan-20-one, etiocholanolone, 5 beta-androstane-3 alpha,17 beta-diol, 3 alpha,17-dihydroxy-5 alpha-pregnan-20-one, androsterone, and 5 alpha-androstane-3 alpha,17 beta-diol. Incubation studies with the testes of the immature hamsters showed that the 5 alpha-C19-steroids were produced from progesterone mainly through 5 alpha-C21-steroids such as 3 alpha,17-dihydroxy-5 alpha-pregnan-20-one, while the 5 beta-C19-steroids were formed through androstenedione and testosterone. The major steroids formed by the testes of suckling and adult animals were 17-hydroxy-4-pregnen-3,20-dione, androstenedione, and testosterone, and little or no 5 beta- and 5 alpha-steroids were produced. The present results demonstrate for the first time that 5 beta-C19-steroids are major C19-steroid products of the gonad.