Profiling of Urinary Glucuronidated Bile Acids across Age Groups

We investigated the age-dependent changes in urinary excretion of glucuronidated bile acids at the C-3 position. Bile acid 3-glucuronides accounted for 0.5% of urinary bile acids in neonates, and the proportion of bile acid 3-glucuronides plateaued at 1-3 years of age. The 3-glucuronides of secondary bile acids were first secreted at 3 months of age, the same time as the establishment of the gut bacterial flora in infants. A considerable portion of bile acid 3-glucuronides were present as non-amidated forms. Our results indicate dynamic hepatic enzyme activity in which the levels of uridine 5 & PRIME;-diphospho-glucuronosyltransferases (UGTs) differ by age group, with higher glucuronidation activity of UGTs towards nonamidated bile acids than amidated bile acids.

Automated summary

In this study, we investigated the age-related changes in urinary excretion of glucuronidated bile acids, finding that the secretion of 3-glucuronides of secondary bile acids coincided with the establishment of gut bacterial flora in infants. Furthermore, the hepatic enzyme activity varied with age, with higher glucuronidation activity towards nonamidated bile acids.