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Bile Acids Conjugation in Human Bile Is Not Random: New Insights from 1 H‐NMR Spectroscopy at 800 MHz
Author(s) -
Nagana Gowda G. A.,
Shanaiah Narasimhamurthy,
Cooper Amanda,
Maluccio Mary,
Raftery Daniel
Publication year - 2009
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/s11745-009-3296-4
Subject(s) - taurine , taurocholic acid , glycocholic acid , bile acid , glycine , cyp8b1 , enterohepatic circulation , chemistry , biochemistry , conjugated system , cholic acid , g protein coupled bile acid receptor , amino acid , nuclear magnetic resonance spectroscopy , stereochemistry , organic chemistry , polymer
Bile acids constitute a group of structurally closely related molecules and represent the most abundant constituents of human bile. Investigations of bile acids have garnered increased interest owing to their recently discovered additional biological functions including their role as signaling molecules that govern glucose, fat and energy metabolism. Recent NMR methodological developments have enabled single‐step analysis of several highly abundant and common glycine‐ and taurine‐ conjugated bile acids, such as glycocholic acid, glycodeoxycholic acid, glycochenodeoxycholic acid, taurocholic acid, taurodeoxycholic acid, and taurochenodeoxycholic acid. Investigation of these conjugated bile acids in human bile employing high field (800 MHz) 1 H‐NMR spectroscopy reveals that the ratios between two glycine‐conjugated bile acids and their taurine counterparts correlate positively ( R 2 = 0.83–0.97; p = 0.001 × 10 −2 –0.006 × 10 −7 ) as do the ratios between a glycine‐conjugated bile acid and its taurine counterpart ( R 2 = 0.92–0.95; p = 0.004 × 10 −3 –0.002 × 10 −10 ). Using such correlations, concentration of individual bile acids in each sample could be predicted in good agreement with the experimentally determined values. These insights into the pattern of bile acid conjugation in human bile between glycine and taurine promise useful clues to the mechanism of bile acids’ biosynthesis, conjugation and enterohepatic circulation, and may improve our understanding of the role of individual conjugated bile acids in health and disease.