Abstract
Epimeric 3α/β-hydroxy-5α/β-pregnan-20-ones and 3β-hydroxy-5-pregnen-20-one were determined in maternal and fetal plasma at term of pregnancy using gas chromatography and electron capture detection. Fifteen sets of plasma samples (maternal vein, umbilical vein and -arteries) were obtained at cesarean section. In fetal and in maternal plasma the metabolites were present mainly in sulfoconjugated form (range 0–1.2 μg/ml). The free steroids, especially in fetal plasma (range 0–170 ng/ml), were sometimes undetectable. 3α-hydroxy-5α-pregnan-20-one and 3β-hydroxy-5α-pregnan-20-one levels were similar in fetal arteries, umbilical vein and maternal vein. A significant arterio-venous difference was observed only for 3α-sulfoxy-5β-pregnan-20-one in cord plasma with higher concentrations in fetal arterial plasma. Pregnenolone sulfate levels in the fetoplacental circulation were higher in fetal arterial plasma (20–2490 ng/ml) than in umbilical vein plasma (0–160 ng/ml). These results show that ring-A-saturated metabolites of progesterone are present in the fetoplacental circulation at concentrations sometimes higher than those of the parent steroid. From the calculation of arterio-venous differences in cord blood it can be concluded that 3α-hydroxy-5β-pregnan-20-one seems to be eliminated more effectively from the fetal compartment than are the 5α-epimers. The possibility that saturated metabolites in the fetoplacental system are derived not only from progesterone but are also formed directly from pregnenolone is discussed.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
