Studies on 16 alpha-hydroxyandrost-4-ene-3, 17-dione in human pregnancy measured by high performance liquid chromatography and radioimmunoassay

Abstract

16 alpha-hydroxyandrost-4-ene-3,17-dione (16 alpha OH-A) was measured in pregnant women by radioimmunoassay (RIA) with specific antiserum. After extraction of the serum the 16 alpha OH-A fraction was separated by the use of Sephadex LH-20 mini column. Lately, high performance liquid chromatograph (HPLC) was combined with RIA (HPLC-RIA) for the measurement of various kinds of steroids from an extract of a serum or urine sample. The purpose of this study was to establish the HPLC-RIA method for the measurement of 16 alpha OH-A in pregnant women. Pooled serum was extracted twice with 5 volumes of ethylether, and the combined extract was separated either by LH-20 mini column with the solvent system n-hexane:benzene:methanol = 8:1:1 or by HPLC ODS column with MeOH:CH3CN:H2O = 60:10:30. The 16 alpha OH-A fraction was collected and an aliquot was measured by RIA. The coefficients of variance for intra and inter-assay (n = 10) were computed to be 8.6 and 12.1% with LH-20, and 7.2 and 11.7% with HPLC, respectively. Recovery rate was 95.7 +/- 7.4% with LH-20 and 92.5 +/- 8.7% with HPLC. The values of 16 alpha OH-A as measured following two kinds of chromatographies were closely related to each other. The mean serum hormone concentrations +/- standard errors were as follows. In maternal peripheral blood up to 11 weeks 1.04 +/- 0.19 (LH-20) and 0.55 +/- 0.10 (HPLC), 12 to 23 weeks 1.22 +/- 0.23 (LH-20) and 0.67 +/- 0.77 (HPLC), 24 to 36 weeks 2.24 +/- 0.42 (LH-20) and 2.27 +/- 0.28 (HPLC), above 37 weeks 1.64 +/- 0.52 (LH-20) and 1.85 +/- 0.34 (HPLC), second stage of labor 5.07 +/- 1.28 (LH-20) and 4.73 +/- 0.54 (HPLC) ng/ml of steroid, respectively, were measured. Steroid concentration in umbilical arterial and venous blood were 7.87 +/- 1.41 (LH-20), 3.75 +/- 0.83 (HPLC) and 8.69 +/- 1.66 (LH-20), 5.38 +/- 0.87 (HPLC) ng/ml, respectively. The values of 16 alpha OH-A levels tended to increase as gestation proceeded. These data suggest production of 16 alpha OH-A by the feto-placental unit. An elevated level of 16 alpha OH-A is found in the umbilical venous blood as compared to the arterial samples. This indicates an extensive conversion. After onset of labor, the 16 alpha OH-A levels were significantly increased because of precursor steroid 16 alpha-hydroxydehydroepiandrosterone-sulfate is mobilized by the stress of labor.(ABSTRACT TRUNCATED AT 400 WORDS)