Plasma Levels of 16α-Hydroxypregnenolone, 16α-Hydroxy-progesterone and 16α-Hydroxydehydroepiandrosterone in the Fetus and Neonates

Abstract

Simultaneous determination of unconjugated 16α-hydroxypregnenolone (16αOH-Preg), 16α -hydroxyprogesterone (16αOH-Prog) and 16α-hydroxy dehydroepiandrosterone (16αOH-DHEA) in fetal and neonatal plasma was performed utilizing a newly developed radioimmunoassay. In all neonates, the three 16α-hydroxysteroid levels were consistently higher in umbilical cord plasma than in the maternal peripheral circulation. 16αOH-Preg in the umbilical arterial plasma increased from 11.2±3.1 at 24 weeks to 29.7±12.0ng/ml at term, 16αOH-Prog from 15.5±3.2 to 34.3±11.0 ng/ml and 16aOH-DHEA from 5.1±1.2 to 5.9 + 1.0 ng/ml. In the anencephalic neonates, only 16αOH-Preg showed an increase pattern under ACTH priming. 16α-OH-Preg levels for normal full term neonates remain relatively constant at the first 24 hr and show a slight decrease at 3 days post partum. In small full term neonates, 16αOH-Preg levels in umbilical arterial plasma are considerably higher than in normal neonates and remain at roughly equivalent levels for the first 5 days post partum. 16αOH-Prog and 16αOHJDHEA levels in umbilical arterial plasma in normal and small full term neonates are almost equal and both groups show a rapid decrease during the first 24 hr. Comparison with findings of the three 16α-hydroxy-steroids in fetal and neonatal plasma is discussed. © 1979, The Japan Endocrine Society. All rights reserved.