STUDIES ON THE AROMATISATION OF NEUTRAL STEROIDS IN PREGNANT WOMEN

Abstract

ABSTRACT In connection with therapeutic abortion, in two patients tracer amounts of dehydro epi androsterone-4- 14 C sulphate (DHAS-4- 14 C) were injected into the umbilical vein and tracer amounts of dehydro epi androsterone-7α- 3 H sulphate (DHAS-7α- 3 H) 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 3 H-labelled metabolites and more than 75 per cent of the 14 C-labelled metabolites recovered from the urine were phenolic in character. More than half of this phenolic radioactive material behaved as oestrone (OE 1 ), 17β-oestradiol (OE 2 ) and oestriol (OE 3 ) when analysed by a modified Brown (1955) method. The OE 3 to OE 1 + OE 2 ratio expressed as 14 C incorporated into these three fractions was significantly higher in both patients than the corresponding ratio of 3 H. Also the 3 H to 14 C ratio of urinary OE 1 significantly exceeded that of OE 3 . The specific activity (S. A.) of OE 3 -7α- 3 H was by far lower than that of OE 1 -7α- 3 H, whereas the S. A. of OE 3 -4- 14 C differed much less from that of OE 1 -4- 14 C. A concept is presented describing the placental barrier to circulating androgen and the role of the placenta in the formation of OE 1 , OE 2 and OE 3 .