Identification and measurement of sulphate-conjugated neutral steroids in the intestinal contents of early and mid-term foetuses.

Abstract

SUMMARY Sulphate-conjugated neutral steroids in the intestinal contents of early and mid-term human foetuses (14–20 weeks of gestation) were investigated by gas—liquid chromatography and gas chromatography—mass spectrometry. Twenty-four neutral steroids were found in the monosulphate fraction and 21 in the disulphate fraction. The total concentration of these steroids varied between 9·6 and 15·3 mg/100 g meconium wet weight, about half being monosulphates and half disulphates. Steroids with a 3β-hydroxy-5-ene structure were found and also saturated steroids which carried hydroxyl groups at carbons 3, 11, 15, 16, 17, 18, 19, 20 or 21. Among them were steroids not previously detected in human foetal compartments. Thus, the foetal meconium is both qualitatively and quantitatively the richest foetal source of neutral steroid sulphates so far investigated. The present results together with those reported in the literature show that in the course of pregnancy there is a many-fold increase in the steroid concentration of the foetal intestinal contents. This is most obvious in the case of saturated C19 steroids and polar pregnane derivatives. Reduction of the 20-ones to 20β-ols seems to be more extensive towards the end of pregnancy. 5, 16-Pregnadienes and 3β-hydroxy-5β-pregnanes are present in higher concentrations in early pregnancy.