[Determination of serum 16 alpha-hydroxydehydroepiandrosterone, 16 alpha-hydroxyestrone and estriol by gas chromatography-mass spectrometry and their perinatal movement].

In order to study the mechanism of estriol (E3) formation in the fetoplacental unit, a method for determining E3 and its precursors, 16 alpha-hydroxydehydroepiandrosterone (16 alpha-OH DHA) and 16 alpha-hydroxyestrone (16 alpha-OH E1) in blood using Gas Chromatography-Mass Spectrometry (GC-MS) was newly developed. Deuterium labelled steroids, 3.4.4.-d3-16 alpha-OH DHA 2.4.17.-d3-E2 and 2.4.-d2-E3 were synthesized and used as the internal standards. After removal of free steroids with ether, the residue was solvolyzed and extracted with ethyl acetate as free form. Steroids were analysed after the formation of T.M.S. and T.F.A. derivative. The values for each steroid in maternal peripheral vein blood (M.V.), umbilical artery blood (U.A.) and vein blood (U.V.) were studied. Conjugated steroid values in M.V. obtained at normal vaginal delivery (13 cases) were as follows: 16 alpha-OH DHA 230.3 +/- 76.3 ng/ml, 16 alpha-OH E1 19.34 +/- 7.00 ng/ml and E3 158.8 +/- 50.2 ng/ml (mean +/- S.D.), respectively. The levels of these three steroids in cord blood were significantly higher than those in maternal blood. These results show that the steroids are actively produced in the fetoplacental unit. A significant increase in all the steroids was associated with labor. None of the values for E3 precursors in umbilical blood correlated with that of conjugated E3 in maternal blood. The significance of 16 alpha-OH DHA and 16 alpha-OH E1 as intermediates of E3 formation in the fetoplacental unit is discussed.