STUDIES ON THE AROMATISATION OF NEUTRAL STEROIDS IN PREGNANT WOMEN

Abstract

In connection with therapeutic abortion, in 2 patients tracer amounts of dehydroepiandrosterone-4-C14 sulphate (DHAS-4-C14) were injected into the umbilical vein and tracer amounts of dehydro-epiandrosterone-7[alpha]-H3 sulphate (DHAS-7[alpha]-H3) into an antecubital vein. The over-all aromatisation of the 2 labelled compounds in the presence of viable fetuses was studied by analyzing the radioactive metabolites excreted in the urine during a period of 6 days. More than 25% of the H3-labelled metabolites and more than 75% of the C14-labelled metabo-lites recovered from the urine were phenolic in character. More than half of this phenolic radioactive material behaved as estrone (OE1), 17[beta]-estradiol (OE2) and estriol (OE3) when analysed by a modified Brown (1955) method. The OE3 to OE1+OE2 ratio expressed as C14 incorporated into these 3 fractions was significantly higher in both patients than the corresponding ratio of H3. Also the H3 to C14 ratio of urinary OE1 significantly exceeded that of OE3. The specific activity (S. A.) of OE3-7[alpha]-H3 was by far lower than that of OE1-7[alpha]-H3, whereas the S. A. of OE3-4-C14 differed much less from that of OE1-C14. 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.