Androgen synthesis in human fetal testis exposed in utero to a combination of norethindrone acetate and ethinyl estradiol.

The effect of norethindrone acetate (NET-Ac) and ethinyl estradiol (EE2) on the 3 beta-hydroxysteroid dehydrogenase (HSD)-delta5-isomerase complex of the human fetal testis was studied by administration of 20 mg NET-Ac and 0.04 mg EE2 p.o on a single day to 4 women, pregnant 10-16 weeks, before abortion was induced, the other 4 patients serving as controls. Testosterone and androstenedione formation from radioactive dehydroepiandrosterone was measured in 8 fetuses by incubation of testicular tissue in vitro. The presence of normal feta Leydig cells was confirmed by electron microscopy. There was no difference between the enzyme activities of testicles in the experimental and control groups. The findins give values of 3 beta-HSD-isomerase activity in human fetal testis and suggest that the steroidogenic function of the fetal testis exposed for a short time to normally used contraceptive steroids remains at the same magnitude.