title: Proton magnetic resonance assay of total and taurine-conjugated bile acids in bile.
abstract: Biliary bile acids, coexisting with phospholipid and cholesterol, are partly conjugated with taurine. In the present report we show that total and taurine-conjugated bile acids in bile can be simultaneously and quantitatively measured by high-resolution (1)H-nuclear magnetic resonance ((1)H-NMR) spectroscopy. We used a 7.05-Tesla NMR spectrometer to obtain the (1)H-NMR spectra of model and biological biles. Only addition of trimethylsilyl-3-propionic acid sodium salt-D(4) (TSP) to each sample as an internal standard was required in preparation for (1)H-NMR measurement. In (1)H-NMR spectra of rat bile, peaks of C-18 methyl protons of bile acids and of C-25 methylene protons on the taurine moiety of taurine-conjugated bile acids were detected at 0.7 ppm and 3.1 ppm, respectively. Peak areas, of C-18 and C-25 peaks, increased in proportion to the concentrations of bile acids or taurine-conjugated bile acids, even in the presence of phospholipid and cholesterol. The accuracy of NMR measurement of total and taurine-conjugated bile acids was confirmed by comparing the results of NMR with those of enzyme-fluorimetry. The results clearly demonstrate that (1)H-NMR spectroscopy can be applied to the quantitative determination of total and taurine-conjugated bile acids in bile without troublesome preparative steps.
authors.affiliation: Third Department of Internal Medicine, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ishikawa
authors.forename: T
authors.initials: T
authors.lastname: Nakashima
authors.forename: K
authors.initials: K
authors.lastname: Inaba
authors.forename: H
authors.initials: H
authors.lastname: Mitsuyoshi
authors.forename: Y
authors.initials: Y
authors.lastname: Nakajima
authors.forename: Y
authors.initials: Y
authors.lastname: Sakamoto
authors.forename: T
authors.initials: T
authors.lastname: Okanoue
authors.forename: K
authors.initials: K
authors.lastname: Kashima
authors.forename: Y
authors.initials: Y
authors.lastname: Seo
mesh_terms: D000818:Animals; D001646:Bile / Q000737:chemistry*; D001647:Bile Acids and Salts / Q000032:analysis*; D002784:Cholesterol / Q000032:analysis; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D010743:Phospholipids / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D013654:Taurine / Q000032:analysis*
chemical_list: D001647:Bile Acids and Salts; D007202:Indicators and Reagents; D010743:Phospholipids; D013654:Taurine; D002784:Cholesterol