STUDIES ON THE AROMATISATION OF NEUTRAL STEROIDS IN PREGNANT WOMEN

Abstract

ABSTRACT In connection with therapeutic abortion, in two patients tracer amounts of dehydroepiandrosterone-4-14C sulphate (DHAS-4-14C) were injected into the umbilical vein and tracer amounts of dehydroepiandrosterone-7α-3H sulphate (DHAS-7α-3H) into an antecubital vein. The over-all aromatisation of the two labelled compounds in the presence of viable foetuses was studied by analysing the radioactive metabolites excreted in the urine during a period of 6 days. More than 25 per cent of the 3H-labelled metabolites and more than 75 per cent of the 14C-labelled metabolites recovered from the urine were phenolic in character. More than half of this phenolic radioactive material behaved as oestrone (OE1), 17β-oestradiol (OE2) and oestriol (OE3) when analysed by a modified Brown (1955) method. The OE3 to OE1 + OE2 ratio expressed as 14C incorporated into these three fractions was significantly higher in both patients than the corresponding ratio of 3H. Also the 3H to 14C ratio of urinary OE1 significantly exceeded that of OE3. The specific activity (S. A.) of OE3-7α-3H was by far lower than that of OE1-7α-3H, whereas the S. A. of OE3-4-14C differed much less from that of OE1-4-14C. A concept is presented describing the placental barrier to circulating androgen and the role of the placenta in the formation of OE1, OE2 and OE3.