STUDIES ON THE AROMATISATION OF NEUTRAL STEROIDS IN PREGNANT WOMEN.

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Abstract
Androst-5-ene-3[beta],16[alpha],17[beta]-triol-7[alpha]-3H was synthesized and the metabolism of this compound was studied in two volunteers following the administration at laparotomy of a tracer dose into the intact foeto-placental circulation. The bulk of the radioactive material recovered from the placenta was in an unconjugated form. From this fraction androst-5-ene-3[beta],16[alpha],17[beta]-triol (A 5-TRIOL), 16[alpha]-hydroxy-testosterone (16[alpha]HO-T) and,oestriol (OE3) were isolated, but no labelled 16[alpha]-hydroxy-dehydr^epiandrosterone (16[alpha]HO-DHA), 16[alpha]-hydroxy-androstenedione (16[alpha]HO-A), 16[alpha]-hydroxy-oestrone (16[alpha]HO-OEi) or 16oxo-17[beta]-oestradiol (I60X0-OE2) were detected. Some 90 per cent of the unconjugated and 77 to 90 per cent of the conjugated radioactive material present in the various foetal tissues was isolated as 5-TRIOL. Oestriol was also isolated, but only from the liver. It was present exclusively in a conjugated form. No conjugated or unconjugated 16[alpha]HO-DHA, 16[alpha]HO-A, 16[alpha]HO-OE1 or 160XO-OE2 was detected in the foetal tissues. The data indicate that the midterm placenta extensively converts A5 -TRIOL into 16[alpha]HO-T and some of the latter into OE3, but that neither the placenta, nor the foetus is capable of converting these ring D glycols into the corresponding ketols. Considerable quantities of OE3, but little, if any, of the 16[alpha]HO-T formed seem to be released by the placenta to the foetus.