Effect of dehydrocholic, chenodeoxycholic, and taurocholic acids on the excretion of bilirubin.

The study explores the impact of various types of bile acid infusion on the discharge of 3-alpha-hydroxy bile acids and bilirubin in specially prepared ponies. It is found that bilirubin excretion appears to be linked with the micelle-forming capacity of endogenous bile acids, as opposed to the nonmicelle-forming attribute of synthetic dehydrocholic acid.

Experimental Design and Procedure

• The study conducted tests on ponies where surgical operations were carried out to create chronic external biliary fistulas.
• The ponies were treated with intravenous bile acid infusion, at about 20% of the average excretion rate.
• The initial bile acid excretion rate dropped to the hepatic synthesis rate during the first 4 to 5 hours of bile drainage.

Outcomes from Different Types of Bile Acids Infusion

• Chenodeoxycholic and taurocholic acid infusions were found to increase bilirubin excretion by 58% to 82%, as observed in Type 1 studies conducted 5 hours after biliary diversion.
• In Type 2 studies, post the 3-hour infusion of dehydrocholic acid, 4 hours after biliary diversion, there was an increase in the bile flow by 45% to 62% and a boosted excretion of 3-alpha-hydroxy bile acid by 34% to 36% above preinfusion levels. Notably, there was no substantial alteration in bilirubin excretion during these surges in bile flow and bile acid excretion.

Comparison and Key Findings

• Following the infusion of dehydrocholic acid, the infusion of taurocholic acid significantly amplified the excretion of bilirubin for 1 hour, with a prolonged excretion level that was two to three times what was caused by dehydrocholic acid infusion.
• One of the intriguing findings from the study was that bilirubin excretion seemed to correlate with the capacity of endogenous bile acids to form micelle, contrasting with the synthetic dehydrocholic acid that lacks this characteristic.