Hagio Masahito, Matsumoto Megumi, Fukushima Michihiro, Hara Hiroshi, Ishizuka Satoshi
Division of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan.
J Lipid Res. 2009 Jan;50(1):173-80. doi: 10.1194/jlr.D800041-JLR200. Epub 2008 Sep 4.
To evaluate bile acid (BA) metabolism in detail, we established a method for analyzing BA composition in various tissues and intestinal contents using ultra performance liquid chromatography/electrospray ionization mass spectrometry (UPLC/ESI-MS). Twenty-two individual BAs were determined simultaneously from extracts. We applied this method to define the differences in BA metabolism between two rat strains, WKAH and DA. The amount of total bile acids (TBAs) in the liver was significantly higher in WKAH than in DA rats. In contrast, TBA concentration in jejunal content, cecal content, colorectal content, and feces was higher in DA rats than in WKAH rats. Nearly all BAs in the liver were in the taurine- or glycine-conjugated form in DA rats, and the proportion of conjugated liver BAs was up to 75% in WKAH rats. Similar trends were observed for the conjugation rates in bile. The most abundant secondary BA in cecal content, colorectal content, and feces was hyodeoxycholic acid in WKAH rats and omega-muricholic acid in DA rats. Analyzing detailed BA profiles, including conjugation status, in a single run is possible using UPLC/ESI-MS. This method will be useful for investigating the roles of BA metabolism under physiological and pathological conditions.
为了详细评估胆汁酸（BA）代谢，我们建立了一种使用超高效液相色谱/电喷雾电离质谱法（UPLC/ESI-MS）分析各种组织和肠内容物中BA组成的方法。从提取物中同时测定了22种个体BA。我们应用该方法来确定两种大鼠品系WKAH和DA之间BA代谢的差异。WKAH大鼠肝脏中总胆汁酸（TBA）的含量显著高于DA大鼠。相反，DA大鼠空肠内容物、盲肠内容物、结肠直肠内容物和粪便中的TBA浓度高于WKAH大鼠。在DA大鼠中，肝脏中几乎所有的BA都以牛磺酸或甘氨酸结合形式存在，而在WKAH大鼠中，结合型肝脏BA的比例高达75%。胆汁中的结合率也观察到类似趋势。在WKAH大鼠的盲肠内容物、结肠直肠内容物和粪便中，最丰富的次级BA是猪去氧胆酸，而在DA大鼠中是ω-鼠胆酸。使用UPLC/ESI-MS可以在一次运行中分析包括结合状态在内的详细BA谱。该方法将有助于研究生理和病理条件下BA代谢的作用。
