title: Alteration of bile acid metabolism in pseudo germ-free rats [corrected].
abstract: To characterize the impact of gut microbiota on host bile acid metabolism, we investigated the metabolic profiles of oxysterols and bile acids (BAs) in a conventional rat model (SD) (n=5) and its pseudo germ-free (GF) equivalent (n=5). GF rats were developed by the oral administration of bacitracin, neomycin and streptomycin (200 mg/kg, each) twice a day for 6 days. Urinary levels of oxysterols and bile acid metabolites were quantified using gas chromatography-mass spectrometry (GC-MS). The activity levels of enzymes involved in the bile acid metabolic pathway were determined through urinary concentration ratio between product to precursor. Cholic acid (CA) and α-/β-muricholic acid (α-/β-MCA) were significantly elevated at pseudo germ-free condition. An increase of hydroxylase (cholesterol 7α-hydroxylase, oxysterol 7α-hydroxylase and cytochrome P450 scc) and a significant decrease of 7α-dehydroxylase were observed. The urinary concentration ratio of primary bile acids, a marker for hepatotoxicity, increased in pseudo germfree conditions. Therefore, it was found that gut microbiota could play a significant role in the bile acids homeostasis and metabolism.
authors.affiliation: Molecular Recognition Research Center, Korea Institute of Science and Technology, Seoul 136-791, Korea.
authors.forename: Salil Kumar
authors.initials: SK
authors.lastname: Bhowmik
authors.forename: Ji Hye
authors.initials: JH
authors.lastname: An
authors.forename: Soo Hyun
authors.initials: SH
authors.lastname: Lee
authors.forename: Byung Hwa
authors.initials: BH
authors.lastname: Jung
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001414:Bacitracin / Q000494:pharmacology; D001647:Bile Acids and Salts / Q000378:metabolism*; D019826:Cholic Acid / Q000378:metabolism; D002793:Cholic Acids / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D041981:Gastrointestinal Tract / Q000382:microbiology; D005856:Germ-Free Life; D006913:Hydroxysteroid Dehydrogenases; D008297:Male; D006899:Mixed Function Oxygenases / Q000378:metabolism; D009355:Neomycin / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013261:Sterols / Q000378:metabolism*; D013307:Streptomycin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D001647:Bile Acids and Salts; D002793:Cholic Acids; D013261:Sterols; D001414:Bacitracin; C004821:muricholic acid; D006899:Mixed Function Oxygenases; D006913:Hydroxysteroid Dehydrogenases; C025376:7 alpha-hydroxysteroid dehydrogenase; D019826:Cholic Acid; D009355:Neomycin; D013307:Streptomycin