OESTROGEN METABOLISM IN THE HUMAN FOETUS

Abstract

ABSTRACT In order to test the validity of a previously advanced hypothesis, that the human foetus actively participates in the oestrogen metabolism of pregnancy attempts were made to introduce different oestrogens into the foetal organism prior to surgical interruption of gestation. Intravenous infusion into the mother of as much as 100 mg of oestriol (oestra-1,3,5(10)-triene-3,16α,17β-triol) resulted in no rise at all in the oestriol concentration of amniotic fluid and only in an extremely limited increase in the conjugated oestriol content of the foetal lungs and livers. It was found that intra-amniotic injection is a most effective way of introducing oestrogen into the foetal organism, since the oestrogen injected is rapidly swallowed (perhaps also aspirated) by the foetus. The administration of 25 mg amounts of 17β-oestradiol (oestra-1,3,5(10)-triene-3,17β-diol) or oestriol by this route resulted in a greatly elevated concentration of conjugated oestrone (3-hydroxy-oestra-1,3,5(10)-triene-17-one) + oestradiol and oestriol, respectively, in a variety of foetal organs, such as the lungs, liver, intestines, and adrenals + kidneys. Especially the lungs seemed to represent a very active site of conjugation, whereas the increase in conjugated oestrogens in the placenta was very limited. Intra-amniotically administered 17β-oestradiol or oestriol rapidly disappeared from the amniotic fluid; it was halved in less than 2 hours and disappeared within 24 hours.