Journal of Clinical Endocrinology & Metabolism, Vol 42, 744-751, Copyright © 1976 by Endocrine Society

ARTICLES

Simultaneous comparison of delta 5-3beta-hydroxysteroid levels in the fetoplacental circulation of normal pregnancy in labor and not in labor

RJ Chang, JE Buster, JL Blakely, DM Okada, CJ Hobel, GE Abraham and JR Marshall

Concentrations of pregnenolone (delta5P), dehydroepiandrosterone (DHEA), 16alpha-hydroxydehydroepiandrosterone (16alpha-OH DHEA), pregnenolone sulfate (delta5P-S), and dehydroepiandrosterone sulfate (DHEA-S) were measured simultaneously by radioimmunoassay in individual, paired umbilical artery (UA) and vein (UV) sera from 18 normal term pregnancies, 6 in labor, 12 not in labor. Mean UA and UV levels +/- SEM (ng/ml) were for delta5P: 30.39 +/- 1.69, 35.55 +/- 3.06; DHEA: 12.31 +/- 2.34, 3.66 +/- 0.38; 16alpha-OH DHEA: 7.48 +/- 0.63, 10.59 +/- 0.78; delta5P-S: 1,652 +/- 154, 1,486 +/- 130; DHEA-S: 2,122 +/- 134, +/- 134, 1,906 +/- 134. Umbilical artery delta5P-S, DHEA- S, and DHEA levels were significantly higher than UV levels, whereas the reverse was true for delta5P and 16alpha-OH DHEA. The inverse arterio-venous (A-V) gradient for 16alpha-OH DHEA was contrary to previous published reports using pooled samples. Comparison by linear regression of paired UA and UV steroid concentrations of delta5P, delta5P-S, DHEA, and DHEA-S revealed a significant correlation (P less than 0.01) for each steroid. Labor was associated with a significant increase in UA levels of DHEA-S and a smaller, but not quite significant, increase in UA levels of delta5P-S, while similar changes for unconjugated delta5-3beta-hydroxysteroids were not observed. Mean A- V gradients between the group of patients in labor and those not in labor were not significantly different. These data demonstrate that: 1) a significant difference between UA and UV concentrations exists for delta5P, DHEA, 16alpha-OH DHEA, delta5P-S, and DHEA-S; 2) there is a significant correlation between UA and UV concentrations for delta5P, DHEA, delta5P-S, and DHEA-S, implying that each fetoplacental unit maintains an equilibrium relative to these steroid concentrations in the umbilical circulation; 3) labor is associated with a significant increase in UA levels of DHEA-S and probably of delta5P-S.