Taurocholate, but not taurodehydrocholate, increases biliary permeability to sucrose

Area of Science:

• Hepatobiliary physiology
• Gastroenterology
• Pharmacology

Background:

• Bile salts are crucial for bile formation and transport.
• The permeability of the biliary tree to solutes is not fully understood.
• Investigating bile salt effects on biliary permeability is important for understanding liver function.

Purpose of the Study:

• To determine if bile salts alter biliary tree permeability to inert solutes.
• To compare the effects of taurocholate and taurodehydrocholate on biliary permeability.
• To elucidate the role of bile salt concentration and micelle formation in biliary permeability.

Main Methods:

• In situ perfused rat liver model.
• Infusion of taurocholate and taurodehydrocholate at varying doses.
• Measurement of bile flow and [14C]sucrose bile-to-plasma ratio.
• Assessment of bile salt secretion rates.

Main Results:

• Tauocholate administration increased bile flow and bile salt secretion in a dose-dependent manner.
• Sucrose bile-to-plasma ratio increased with taurocholate infusion, indicating enhanced biliary permeability.
• Taurodehydrocholate caused choleresis but did not alter sucrose bile-to-plasma ratio, suggesting micelle formation is key.
• Bile flow decreased when taurocholate secretory rate was exceeded.

Conclusions:

• Tauocholate, but not taurodehydrocholate, increases biliary permeability to inert solutes in a dose-dependent manner.
• The findings suggest that micelle-forming bile salts are responsible for altering biliary tree permeability.
• This has implications for understanding solute transport and drug delivery within the biliary system.