[A study of 16 alpha OH-DHA and 16 alpha OH-pregnenolone in feto-placental unit (author's transl)].

Serum levels of total 16 alpha-hydroxydehydroepiandrosterone (16 alpha-OH-DHA) and 16 alpha-hydroxy-pregnenolone (16 alpha-OH-P5) which are considered to be a fetal origin have not been well documented. Radioimmunoassays using specific antisera against 16 alpha-PH-DHA-7-CMO-BSA and 16 alpha-OH-P5-#-succinate-BSA were developed and serum concentrations of these steroids in normal men and women, maternal peripheral vein (MV) during pregnancy, umbilical artery and umbilical vein at delivery were measured. Labeled 16 alpha-hydroxylated steroids were synthesized by microbiological method. The concentrations of 16 alpha-OH-delta 5-steroids were increased as pregnancy progresses. Both steroid levels in cord serum were statistically higher than those in MV. In the case of intrauterine fetal death and anencephalic pregnancy, significantly low levels of both steroids in MV and cord blood were found. On the other hand, pregnancy with placental sulfatase deficiency, showed high levels both in MV and cord vein. It is interesting to not that in normal pregnancy, maternal 16 alpha-OH-DHA levels correlated well with that of 16 alpha-OH-P5. However, in pregnancy with anencephalic fetus, there was no correlation between the levels of two steroids. From the results of in vitro experiment using placental tissue, 16 alpha-OH-progesterone was formed from labeled 16 alpha-OH-P5, whereas no metabolite was noticed when fetal adrenal tissue was used. From these in vitro and in vivo studies, a significance of the measuring of serum 16 alpha-OH-DHA and 16 alpha-OH-P5 during pregnancy is discussed.