Metabolism of 15α-Hydroxyestradiol in Human Pregnancy1

15α-Hydroxyestradiol (15α-OHE2) was given iv to two pregnant women at 31 and 33 weeks gestation and urine was collected for 6 days. Excretion was almost complete during this period (93% and 96%). Separation of metabolites according to conjugate types was effected by chromatography on alumina and Sephadex G-10 and in one instance, DEAE-Sephadex A-25. Individual conjugates were purified by Celite partition chromatography. Each metabolite was assayed by treatment with an appropriate enzyme and subsequent purification of the aglycone, usually by Celite chromatography and isotope dilution techniques. About 70% of the radioactivity was identified. The predominant conjugates were the 15-N-acetylglucosaminides (35%) and 3-sulfate-15-N-acetylglucosaminides (21%) of 15α-hydroxyestrone (15α-OHE1 and 15α-OHE2. No other N-acetylaminoglucosides were detected. The major glucosiduronates (14%) were those of 15α-OHE1, 15α-OHE2, estetrol (E4) and of a metabolite hitherto not reported in the human, 15α-OHE2-17α. Th...