Developmental pattern of urinary ketonic bile acids during the neonatal period

We tested the hypothesis that healthy neonates and infants excrete in the urine ketonic bile acids, delta 4-3-oxo bile acids and delta 1-3-oxo bile acids. The hypothesis is based on the finding of ketonic bile acids in amniotic fluid at full term. We measured the urinary concentration of ketonic bile acids during the neonatal period. Urine from 24 healthy full-term infants (aged 3 d and 1, 2, and 3 mo, six per group) was analyzed for bile acids by gas chromatography-mass spectrometry with selected ion monitoring. Large amounts of ketonic bile acids were detected in the urine of healthy neonates and infants. The concentration of ketonic bile acids in urine at age 3 d was significantly higher than at age 1, 2, or 3 mo (P < 0.01, P < 0.01, P < 0.001, respectively). This study demonstrates that healthy new-born infants excrete large amounts of ketonic bile acids in the urine.