Androgen Formation from Pregnenolone Sulfate by Fetal, Neonatal, Prepubertal and Adult Human Testes

To evaluate steroid sulfatase activity in fetal, neonatal, prepubertal and adult human testes, homogenates of testicular tissue were incubated with 3H-pregnenolone sulfate. Rate of cleavage of pregnenolone sulfate and the production of metabolites were measured. Free steroid products were isolated, identified and the amounts produced in 2-hr expressed as pmoles/mg protein incubated. On this basis, the rate of cleavage of pregnenolone sulfate in testes from the various stages of development did not show marked changes. A definite correlation was demonstrated between the age of the subject and the amounts of free C19 steroids produced by testicular homogenates. Testicular homogenates from 3 fetuses (107–152 days) yielded the same amount of testosterone, 1.29–1.38 pmoles/mg protein. Homogenates from a 3-week-old infant produced 0.22 pmoles/mg protein. No testosterone was formed in the testicular homogenates from 2-month, 14-month and 9-yr-old subjects. Homogenates from adults 19, 23, and 52 yr old synthesized 3.9, 1.6 and 0.9 pmoles/mg protein respectively. The capacity to convert pregnenolone sulfate to the C19 steroids, dehydroepiandrosterone, androstenedione and testosterone, was greatest in testes from the youngest fetus and decreased reaching a minimum in the testes of the 9 yr old. The androgen forming capacity of testes from the youngest adult was equal to that of the oldest fetus and decreased with increasing age. The changes observed in the capacity of testes from different stages of development to convert pregnenolone sulfate to testosterone correlate with previous reports on the histologic changes in the testis as well as plasma testosterone levels in male subjects from birth to adulthood.