Bile acids (BAs) are major components of bile synthesized from cholesterol and take part in the digestion of dietary lipids, as well as having signaling functions. They undergo extensive microbial metabolism inside the gastrointestinal tract. Here, we present a method of ultra-high pressure liquid chromatography coupled to ion trap mass spectrometry for quantification of 45 BAs in mouse cecum. The system was validated in regard to sensitivity with limits of detection and quantification (0.6–24.9 nM), interday accuracy (102.4%), interday precision (15.2%), recovery rate (74.7%), matrix effect (98.2%) and carry-over effect (<1.1%). Afterwards, we applied our method to investigate the effect of metformin on BA profiles. Diabetic mice were treated with metformin for 1 day or 14 days. One day of treatment resulted in a significant increase of total BA concentration (2.7-fold increase; db/db metformin 5.32 μmol/g, db/db control mice 1.95 μmol/g), most notable in levels of 7-oxodeoxycholic, 3-dehydrocholic and cholic acid. We observed only minor impact on BA metabolism after 14 days of metformin treatment, compared to the single treatment. Furthermore, healthy wild type mice had elevated concentrations of allocholic and ω-muricholic acid compared to diabetic mice. Our method proved the applicability of profiling BAs in cecum to investigate intestinal BA metabolism in diabetes and pharmacological applications.

胆汁酸（BAs）是由胆固醇合成的胆汁的主要成分，并参与饮食脂质的消化，并具有信号传导功能。它们在胃肠道内经历广泛的微生物代谢。在这里，我们介绍了一种超高压液相色谱与离子阱质谱联用的方法，用于定量小鼠盲肠中的45个BA。该系统在灵敏度方面进行了验证，包括检测和定量极限（0.6-24.9 nM），日间准确性（102.4％），日间准确性（15.2％），回收率（74.7％），基质效应（98.2％）和携带过度效应（<1.1％）。之后，我们应用我们的方法研究二甲双胍对BA谱的影响。用二甲双胍治疗糖尿病小鼠1天或14天。db / db二甲双胍为5.32μmol/ g，db / db对照小鼠为1.95μmol/ g，最显着的是7-氧代脱氧胆酸，3-脱氢胆酸和胆酸的水平。与单药治疗相比，二甲双胍治疗14天后对BA代谢的影响很小。此外，与糖尿病小鼠相比，健康的野生型小鼠的尿酸和ω-甲酚酸浓度较高。我们的方法证明了在盲肠中分析BA的适用性可用于研究肠道BA在糖尿病中的代谢和药理学应用。