Isolation of an Estriol Precursor, 16α-Hydroxydehydroepiandrosterone, from Human Umbilical Sera

Abstract

Pooled human umbilical sera carried through ethanol /ether extraction, solvolysis and lipid separation resulted in an extract with the chromatographic mobility of 16-hydroxydehydroepiandrosterone (16-OHDHEA) in several chromatographic systems. The compound gave a weak blue tetrazolium reaction, a good Pettenkoffer assay, and a characteristic color to H₂So₄/C₂H₅OH. The infrared spectra of the free precursor compared favorably with that of the standard 16-OH-DHEA, while their acetate derivatives demonstrated essential identity. Like the standard, the steroid was converted to estriol by the human placenta. Proof of estriol formation was demonstrated by migration in 2 paper chromatographic systems, by Kober measurement of estriol methyl ether after methylation and alumina chromatography, and by a positive Bachman reaction. In incubations with excess amounts of 16-OH-DHEA, presence of the intermediary 16-hydroxyandrostenedione was suggested by movement of a compound parallel with standard 16-hydroxyandrostenedione in 3 chromatographic systems, and by its conversion to estriol by the placenta. A major role for 16-OH-DHEA in estriol synthesis in pregnancy is proposed.