[Metabolism of pregnenolone sulfate in feto-placental unit].
In order to study the metabolic fate of circulating pregnenolone sulfate (P5S) during pregnancy, 30 mg of newly synthesized tetra (2,2,4,6)-deuterated P5S was administered to the maternal vein 60 minutes prior to cesarean section at term. All pregnant women were volunteers and had been informed of nature of this study. The placenta, maternal urine and blood samples from maternal vein (MV), umbilical cord (U) were collected and deuterated metabolites were analysed by gas chromatography mass spectrometry with a multiple ion detector. Total amounts of metabolites were measured and the ratio of deuterated steroid to the total amounts were calculated (d%). d% of P5S, 16 alpha OH-P5S, 17 alpha OH-P5S, 20 alpha-dihydro-P5S (20P5S), 20P5 and progesterone (P4) in MV were 84.5, 51.6, 95.5, 85.1, 71.2 and 10.9%, respectively. In the placental tissue, 20P5, 20P4 and P4 were also found and d% of these steroids were calculated as 16.1, 3.2 and 3.1%. Only P4 was found with d% of 11.2% in U. In the urine collected for 2 hours after deuterated P5S administration, P5S (40.6%), 20P5S (56.6%) and pregnanediol (34.8%) were identified. Deuterated C19, C18 steroids were not detected in any of the samples studied. When 30 mg of non labeled P5S was also administered to MV at term, the levels of P5S, 20P5S, P4 and 20P4 in MV rose, but the levels of DHA-S were not changed. These results indicate that the circulating P5S in MV can be a precursor of 20P5S, 17P5S, 16P5S, 20P4 and P4, but can not be the precursor of C19, C18 steroid.
D005260:Female; D005333:Fetus / Q000378:metabolism*; D006801:Humans; D008431:Maternal-Fetal Exchange; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy / Q000378:metabolism*; D011263:Pregnancy Trimester, Third; D011284:Pregnenolone / Q000378:metabolism*
C018370:pregnenolone sulfate; D011284:Pregnenolone