Hepatocellular transport system

The hepatocellular transport system is a complex network of membrane-bound proteins located on the basolateral (sinusoidal) and apical (canalicular) membranes of hepatocytes. These transporters, primarily belonging to the Solute Carrier (SLC) and ATP-Binding Cassette (ABC) superfamilies, facilitate the bidirectional movement of endogenous substances—such as bile acids, bilirubin, and hormones—and exogenous compounds like drugs and toxins. Sinusoidal transporters like OATP1B1 and NTCP mediate the uptake of compounds from the blood, while canalicular transporters like BSEP and MDR1 drive the excretion of metabolites into the bile. This system is a fundamental determinant of hepatic clearance and systemic drug exposure, making it a focal point for pharmacokinetics and toxicology. Genetic polymorphisms or pharmacological inhibition of these transporters can lead to impaired bile flow (cholestasis), hyperbilirubinemia, and severe drug-drug interactions. Consequently, evaluating the interaction of new chemical entities with the hepatocellular transport system is a regulatory requirement in drug development to mitigate the risk of hepatotoxicity and adverse clinical outcomes.

Other names

Hepatic transport systemHepatocyte transportersLiver transport systemSinusoidal and canalicular transport system

Inhibition of hepatic uptake transporters (e.g., OATP1B1/1B3), inhibition of bile salt export pump (BSEP), or acting as competitive substrates for hepatic clearance.