title: Tauroursodeoxycholate increases rat liver ursodeoxycholate levels and limits lithocholate formation better than ursodeoxycholate.
abstract: OBJECTIVE
  To explain the greater hepatoprotective effect of tauroursodeoxycholic acid vs. ursodeoxycholic acid, the absorption, hepatic enrichment, and biotransformation of these bile acids (250 mg/day) were compared in rats.
  
  
  METHODS
  Bile acids were determined in intestinal contents, feces, urine, plasma, and liver by gas chromatography-mass spectrometry.
  
  
  RESULTS
  The concentration of ursodeoxycholate in the liver of animals administered tauroursodeoxycholic acid (175 +/- 29 nmol/g) was greater (P < 0.05) than in animals administered ursodeoxycholic acid (79 +/- 19 nmol/g). Hepatic lithocholate was substantially higher after ursodeoxycholic acid administration (21 +/- 10 nmol/g) than after tauroursodeoxycholic acid administration (12 +/- 1 nmol/g). A concomitant reduction in the proportion of hydrophobic bile acids occurred that was greatest during tauroursodeoxycholic acid administration. In the intestinal tract, the mass of ursodeoxycholate and its specific metabolites was greater in rats administered tauroursodeoxycholic acid (27.2 mg) than those administered ursodeoxycholic acid (13.2 mg). In feces, the proportion of lithocholate was 21.9% +/- 4.9% and 5.4% +/- 4.0% after ursodeoxycholic acid and tauroursodeoxycholic acid administration, respectively.
  
  
  CONCLUSIONS
  Compared with ursodeoxycholic acid, tauroursodeoxycholic acid induces a greater decrease in the percent composition of more hydrophobic bile acids within the pool, limits lithocholate formation, and increases hepatic ursodeoxycholate concentration. These differences are explained by increased hepatic extraction and reduced intestinal biotransformation and not by enhanced absorption of the amidated species.
authors.affiliation: Department of Pediatrics, Children's Hospital Medical Center, Cincinnati, Ohio, USA.
authors.forename: C M
authors.initials: CM
authors.lastname: Rodrigues
authors.forename: B T
authors.initials: BT
authors.lastname: Kren
authors.forename: C J
authors.initials: CJ
authors.lastname: Steer
authors.forename: K D
authors.initials: KD
authors.lastname: Setchell
mesh_terms: D000042:Absorption; D000818:Animals; D001711:Biotransformation; D005243:Feces / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D007422:Intestines / Q000737:chemistry; D008095:Lithocholic Acid / Q000096:biosynthesis*; D008099:Liver / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D010949:Plasma / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D013655:Taurochenodeoxycholic Acid / Q000032:analysis / Q000378:metabolism*; D014556:Urine / Q000737:chemistry; D014580:Ursodeoxycholic Acid / Q000032:analysis / Q000378:metabolism*
chemical_list: D013655:Taurochenodeoxycholic Acid; D008095:Lithocholic Acid; C031655:ursodoxicoltaurine; D014580:Ursodeoxycholic Acid