Figure 5.

Metformin alters fecal levels of short-chain fatty acids, bile acids, and other metabolites. Levels of short-chain fatty acids (SCFAs), branched-chain fatty acids, amino acids, bile acids, and phenolic metabolites were measured in fecal samples of mice at baseline (Met0), after 1 week of metformin treatment (Met1), after 2 weeks of metformin treatment (Met2), and for age-matched controls of Met2 (Cntrl2). (A) Elevated levels of fecal butyrate were detected in Met2 compared to Met0. (B) Fecal propionate was increased in Met2 compared to Cntrl2. (C–E) Quantitative boxplots comparing Met0 to Met2 revealed elevations of fecal (C) cholic acid, (D) deoxycholic acid, and (E) isodeoxycholic acid in Met2 compared to Met0. (F–H) In contrast, metformin treatment decreased fecal levels of (F) lithocholic acid, (G) alloisolithocholic acid, and (H) 3-oxo-lithocholic acid. Statistical testing was performed using the Wilcoxon signed-rank tests, with P values adjusted by false discovery rate using the Benjamini-Hochberg method.