Reversible cholestasis induced by bromosulfophthalein in rabbits with enterohepatic circulation of bile acids maintained.

The effects of a constant infusion of bromosulfophthalein (BSP) at a rate exceeding its maximum excretory transport (Tm) on biliary secretion were investigated in anaesthetized rabbits with the enterohepatic circulation of bile acids (EHC) maintained by bile administration into the duodenum. BSP infusion resulted in a significant cholestasis coursing with decreases in the biliary output of sodium, bicarbonate and chloride. The Tm for total BSP was greater than that described in this species with the EHC interrupted but smaller than that noted after intravenous administration of bile acids. It is proposed that the cholestatic effect of BSP may be mainly due to a reduction of the bile acid-independent fraction of bile flow owing to the acute toxic effect of unconjugated BSP on the hepatic ATPase involved in the formation of this bile fraction. Possible explanations for the Tm values and other aspects of BSP metabolism and biliary excretion in the rabbit are discussed.