Tetrahydroxylated bile acids in healthy human newborns.

Urine was collected in four healthy infants, born after 35-39 weeks of gestation. The collections were made for 24 h starting immediately after birth. Bile acids were extracted, separated into conjugate groups, solvolysed, hydrolysed and quantified by gas-liquid chromatography as methyl ester trimethylsilyl ether derivatives. Identification was made by gas-liquid chromatography-mass spectrometry. Cholic acid was the predominating primary bile acid. Non-sulphated tetrahydroxylated bile acids, tentatively identified as 1,3,7,12- and 3,6,7,12-tetrahydroxycholanoic acids, were present in almost the same amounts as cholic acid. A previously unknown tetrahydroxylated cholanoic acid, which might be 2-hydroxylated hyocholic acid, was found in all infants in similar amounts. 3 beta-Hydroxy-5-cholenoic acid was present in the sulphate fraction in the urine from all infants. Lithocholic acid was not found. Small amounts of allo and 6-hydroxylated bile acids were mainly found in the sulphate fraction. Bile acids hydroxylated in the 1-position were found predominantly in the taurine fraction.