Regulation of biliary protein secretion in dogs

The biliary secretion of protein in response to bile acids and other agents known to increase bile flow was examined in a chronic bile fistula dog model. Infusion of 25, 50, or 75 mumole/kg/hr sodium taurocholate after 3 hr of bile fistulization increased biliary protein output significantly by 52, 86, and 108% respectively compared to preinfusion values. A proportionate increase in biliary albumin output during taurocholate choleresis was demonstrated. Protein outputs during bile fistulization without taurocholate replacement were unchanged. The non-micelle-forming bile acid dehydrocholate markedly increased bile flow but did not change protein output. Similarly, the hormonal choleretics glucagon and secretin caused significant decreases in biliary protein concentration but no change in protein output. These data indicate a correlation between biliary protein secretion and bile acid-dependent bile flow. It is likely that regulation of certain proteins is dependent on the micelle-forming properties of bile acids.