是胆汁的重要成分，在脂肪代谢中起着重要作用。 胆汁酸主要存在于肠肝循环系统并通过再循环起一定的保护作用。做代谢研究中有的会涉及到提取 中的胆汁酸。经过查询资料后，总结了一下粪便中胆汁酸的提取方法，供大家参考：
（3）Fecal samples were lyophilized and weighed. For extraction of bile acids, an aliquot of dried feces (5 mg) was incubated in 1 mL alkaline methanol (methanol: 1 mol/L NaOH 3:1 [vol/vol]) for 2 hours at 80°C in screw-capped tubes using nor-hyodeoxycholate as an internal standard. Then 9 mL of distilled water was added, and the tubes were mixed and centrifuged. The supernatant was subsequently applied to a prepared Sep-Pak C18 solid-phase extraction cartridge. After a clean up by wash procedures, bile acids were eluted with 75% methanol. The solvent was evaporated to dryness, and the bile acids were derivatized by incubation with 50 μL trifluoroacetic anhydride and 30 μL 1,1,1,3,3,3-hexafluoro-2-propanol for 1 hour at 60°C. The bile acid derivatives were separated on a 25 m×0.25 mm capillary GC column (CP Sil 5B, Chrompack International) in a 3800 GC gas chromatograph (Varian) equipped with a flame ionization detector. The injector and the flame ionization detector were kept at 300°C. The column temperature was programmed from 230 to 280°C. Bile acid derivatives were introduced by split injection (split ratio, 20:1).
Post SM, de Crom R, van Haperen R, van Tol A, Princen HM. Increased fecal bile acid excretion in transgenic mice with elevated expression ofhuman phospholipid transfer protein. Arterioscler Thromb Vasc Biol. 2003,23(5):892-897.