OESTRIOL METABOLISM IN THE HUMAN FOETO-PLACENTAL UNIT

Abstract

ABSTRACT At laparotomy 1 to 2 μc amounts of oestriol-16-14C were injected into the umbilical vein of 3 foetuses and the foeto-placental unit was left in situ with an intact circulation for a few minutes prior to the removal of the products of conception. More than 90 per cent of the radioactivity present in the various foetal tissues consisted of oestriol-3-sulphate. In addition, a small amount of oestriol-16(17?)-glucosiduronate was identified in extracts of foetal liver. In contrast to the pattern found in foetal tissues, the bulk of radioactivity in the placenta and membranes was present as unconjugated oestriol. In two cases at laparotomy the placenta was disconnected from the foetus and was perfused in situ with 0.4 μc of oestriol-16-14C-3-sulphate. More than 80 per cent of the radioactivity present in the placenta was identified as unconjugated oestriol. The results indicate that oestriol-3-sulphate formed by the foetus becomes hydrolyzed to a significant extent by the placenta.