Effect of Reduction of the Intestinal Microflora on the Excretion of Neutral Steroids in Human Faeces and Urine

Neutral steroid glucuronides and mono‐ and disulphates in faeces and urine of normal adult males were analysed before and during phthalylsulphathiazole treatment in order to clarify whether faecal and urinary excretion of C19 and C21 steroids is modified by reduction of the intestinal microflora. For the same purpose, the unconjugated neutral steroids in faeces were analysed, too. During the sulphonamide treatment, the profile of faecal neutral steroid sulphates became very similar to that in bile. The amount of sulphate‐conjugated neutral steroids, especially disulphates, was increased and the pattern of the faecal steroids indicated a decrease in the oxidoreducing and epimerising activities of the intestinal contents. No neutral steroid glucuronides were detected in faeces either before or during the sulphonamide treatment. The urinary excretion of neutral steroid conjugates was very little affected by the administration of the drug. However, most of the 16‐hydroxylated C19 steroid monosulphates were excreted in urine in larger amounts during the treatment than before it. The results obtained indicate that in normal adult subjects changes in the composition of the intestinal microflora greatly modify faecal steroid excretion, but seem to be of very little importance for the urinary output of a large number of neutral steroid conjugates.