Comparative effects of deoxycholate and 7-methyl-deoxycholate in the hamster

Area of Science:

• Biochemistry
• Hepatology
• Pharmacology

Background:

• Bile acids are crucial for digestion and maintaining cholesterol homeostasis.
• Altered bile acid metabolism is implicated in gallstone formation (cholelithiasis).
• Deoxycholic acid (DCA) is a secondary bile acid with known metabolic effects.

Purpose of the Study:

• To investigate the metabolism and effects on biliary lipids of 7-methyl-deoxycholic acid (7-MDCA) in hamsters.
• To compare these effects with those of deoxycholic acid (DCA).

Main Methods:

• 14C-labeled 7-MDCA and DCA were administered to bile fistula hamsters.
• Hepatic bile was analyzed for radioactive metabolites and biliary lipid outputs.
• Metabolic fate, including absorption, hepatic extraction, and biliary excretion as conjugates, was assessed.

Main Results:

• Both 7-MDCA and DCA were efficiently absorbed, extracted by the liver, and conjugated.
• DCA underwent 7 alpha-hydroxylation to cholic acid; 7-MDCA did not.
• DCA infusion increased bile lithogenicity, while 7-MDCA stimulated phospholipid secretion, reducing lithogenicity.
• Both bile acids exhibited toxicity, causing hemolysis and respiratory distress in hamsters.

Conclusions:

• 7-MDCA demonstrates a favorable effect on biliary lipid composition compared to DCA.
• 7-MDCA's resistance to hydroxylation may contribute to its altered metabolic profile.
• Further research is needed to explore the therapeutic potential and safety of 7-MDCA, despite observed toxicity.