Profile of Bile Acids in Biological Fluids of Human Fetus and Neonate and Congenital Metabolic Disordere

Abstract

Unusual 1 β-and 6 α-hydroxylated and Δ-unsaturated bile acids were identified from meconium, amniotic fluid and neonatal urine by comparison with the mass spectra of the synthetic standards. In the profile analysis of fetal bile acids, 1 β-hydroxylated cholic acid was predominant in full term amniotic fluid, and neonatal urine, while 6 α-hydroxylated chenodeoxycholic (hyocholic) acid constituted a main component in meconium. Quantity of these bile acids increased according to the progress of gestation and decreased with developmental age after birth. Taurine conjugates are main bile salts in meconium and were exchanged progressively for the glycine conjugates in neonatal biles. These results suggest that hydroxylation at C-1 β or C-6α position and conjugation of bile acids with taurine in fetal liver might be carried out for the elimination of bile acids. Biosynthetic intermediates for the bile acids were synthesized efficiently, and C₂₇-bile acids were determined in the urine of an infant with Zellweger syndrome. There is a review on the fetal bile acid metabolisms and congenital diseases.