Profile of urinary bile acids in infants and children: Developmental pattern of excretion of unsaturated ketonic bile acids and 7 beta-hydroxylated bile acids
A. Kimura et al., Profile of urinary bile acids in infants and children: Developmental pattern of excretion of unsaturated ketonic bile acids and 7 beta-hydroxylated bile acids, PEDIAT RES, 45(4), 1999, pp. 603-609
Unusual bile acids, such as unsaturated ketonic and 7 beta- hydroxylated bi
le acids, have been detected in urine early in life. To elucidate the norma
l profiles of usual and unusual urinary bile acids in the neonatal and pedi
atric periods, we measured the concentrations of 28 kinds in urine from nor
mal newborns, infants, and children by gas chromatography-mass spectrometry
. The mean total bile acid/Cr ratio in 7-d-old infants was significantly hi
gher than in subjects of other age groups (birth, 2-4 mo, 5-7 mo, 11-12 mo,
2-3 y, 9-14 y, and adult) (p < 0.05). Relatively large amounts of unusual
bile acids were detected during infancy, especially during the period up to
1 mo of age. At that time, 1 beta,3 alpha,7 alpha,12 alpha-tetrahydroxy-5
beta-cholan-24-oic, 7 alpha,12 alpha-dihydroxy-3-oxo-5 beta-chol-1-en-24-oi
c, and 7 alpha,12 alpha-dihydroxy-3-oxo-4-cholen-24-oic acids were predomin
ant among the unusual urinary bile acids present. Moreover, the levels of 3
alpha,7 beta,12 alpha-trihydroxy-5 beta-cholan-24-oic acid increased signi
ficantly after 2-4 mo of age. These results indicate that bile acid synthes
is and metabolism in the liver of developing infants are significantly diff
erent from that occurring in the Liver of adults. Significant amounts of ur
inary isomerized 7 beta-hydroxylated bile acids were detected after late in
fancy, probably because of changes in the intestinal bacterial flora respon
se to a change in nutrition. We describe, for the first time, evidence of t
he epimerization of the 7 alpha-hydroxyl group of cholic acid, which may be
unique to human development.