Role of bile ducts during secretin choleresis in dogs

Abstract

Trained, unanesthetized, cholecystectomized dogs were infused with secretin via indwelling catheters in hepatic artery, splenic vein, and peripheral vein. Increments in bile flow were 1.5 times greater during hepatic arterial than during splenic venous infusion and 1.2 times greater during splenic venous than during peripheral venous infusion. Increments in bicarbonate excretion rate showed similar relationships. Since bile ducts are supplied mainly by hepatic artery this suggests that secretin acts mainly on the duct system, but responsive tissue must also receive at least part of its blood supply from the portal vein. In other studies bromsulphalein (BSP) was infused at constant rate and the quantity of extra BSP washed out during secretin or taurocholate choleresis was used to calculate an apparent biliary "washout volume." This was 0.5-3 ml less during secretin than during taurocholate choleresis. The results of both types of experiments indicate that mechanisms responsible for secretion choleresis are located in the bile ducts or ductules.