2-Hydroxylation and O-methylation of oestrogens by human placenta in vivo.
Concentrations of unconjugated and conjugated 2-hydroxyoestrogens and their 2-methylethers were determined by radioimmunoassay in serum obtained from the umbilical artery, umbilical vein, retroplacental space, and maternal peripheral vein at the time of delivery. The concentrations of unconjugated 2-hydroxyoestrogens and 2-methoxyoestrogens were found to be significantly higher in the post-placental vessels than in the pre-placental vessels. On the basis of the concentrations measured it was estimated that the placenta secretes about 1.4 nmol/min 2-hydroxyoestrogens and about 1.7 nmol/min of 2-methoxyoestrogens. The present in vivo findings confirm the placental 2-hydroxylase- and catechol-O-methyl-transferase activities previously demonstrated in vitro.
D004967:Estrogens / Q000378:metabolism*; D005260:Female; D005312:Fetal Blood / Q000032:analysis; D006801:Humans; D006900:Hydroxylation; D008745:Methylation; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy / Q000378:metabolism*
D004967:Estrogens