(A) Quantification of bile acid metabolites in the cecum and cecal contents from SPF and GF mice. Blue and yellow arrows indicate host- and bacteria-mediated enzymatic responses, respectively. N.D., not detected (<0.010 nmol per tissue). (B) Metabolic pathway map of bile acids in mice, related to (A). Sult, sulfotransferase; HDSH, hydroxysteroid dehydrogenase; BAAT, bile acid–CoA:amino acid N-acyltransferase; BACS, bile acid–CoA synthetase; Cyp, cytochrome P450; BSHs, bile salt hydrolases. (C) Tissue distribution of CA7S in various tissues of SPF and GF mice. N.D., not detected (<0.010 pmol/mg). (A and C) Data are presented as the means ± SD from experiments with three or more mice per group and are representative of two independent experiments. *P < 0.05, ***P < 0.005, and ****P < 0.001 by two-tailed, unpaired Student’s t tests with Benjamini-Hochberg correction.