EXCRETION OF CONJUGATES OF NEUTRAL STEROIDS IN HUMAN BILE DURING LATE PREGNANCY

ABSTRACT 10 C19 and 21 C21 steroids were identified and most of them estimated in in the glucuronide and mono- and disulphate fractions of human pregnancy bile. Total amounts of 60–70 mg/100 ml were found in the gallbladder bile samples studied, indicating that the biliary route of excretion is of great importance in the metabolism of neutral steroids during pregnancy. Isomers of pregnanolone and pregnanediol predominated, and considerable amounts of 16α- and 21-hydroxylated C21O3 steroids were also found. These compounds are probably mainly maternal metabolites of progesterone, which is produced in large amounts by the foeto-placental unit. The concentrations of C19 steroids were small in comparison with those of C21 steroids. It seems that the proportion of steroid sulphate excretion in bile in relation to glucuronides is increased during pregnancy. Unconjugated steroids were not found in the bile samples studied.