Developmental pattern of 3-oxo-Δ4 bile acids in neonatal bile acid metabolism

AIMS: To investigate whether a fetal pathway of bile acid synthesis persists in neonates and infants. METHODS: 3-oxo-delta 4 bile acids were determined qualitatively and quantitatively in the urine, meconium, and faeces of healthy neonates and infants, using gas chromatography-mass spectrometry. RESULTS: The mean percentage of 3-oxo-delta 4 bile acids in total bile acids in urine at birth was significantly higher than that at 3 or 7 days, and at 1 or 3 months of age. The concentration of this component in meconium was significantly higher than that in faeces at 7 days and at 1 or 3 months of age. CONCLUSIONS: The presence of large amounts of urinary 3-oxo-delta 4 bile acids may indicate immaturity in the activity of hepatic 3-oxo-delta 4-steroid 5 beta-reductase in the first week of postnatal life. Large amounts of this component in meconium may be due to the ingestion of amniotic fluid by the fetus during pregnancy.