Tetrahydroxylated bile acids in healthy human newborns

Abstract. 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 β ‐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.