Solute carrier organic anion transporter family member 1B1 and Solute carrier organic anion transporter family member 1B3 (OATP1B1/1B3)

Human OATP1B1 and OATP1B3 are critical uptake transporters located on the sinusoidal (basolateral) membrane of hepatocytes, where they facilitate the entry of various substances from the blood into the liver (ResearchGate, 2025; NIH, 2020). They belong to the solute carrier organic anion (SLCO) family and are essential for the hepatic clearance of endogenous compounds like bilirubin and bile acids, as well as a wide array of drugs including statins, antibiotics, and anticancer agents (MDPI, 2021; NIH, 2011). Because they serve as the primary gateway for many drugs to reach their site of metabolism or action in the liver, their function is a major determinant of systemic drug exposure and pharmacokinetics (NIH, 2020). Genetic polymorphisms, particularly in the SLCO1B1 gene (e.g., the *5 variant), can significantly reduce transporter activity, leading to elevated plasma drug levels and increased risks of toxicity, such as statin-induced rhabdomyolysis (NIH, 2020; MDPI, 2021). Additionally, these transporters are frequent sites of drug-drug interactions, as many medications can inhibit their activity and cause sudden increases in the concentration of co-administered substrates (NIH, 2020). The complete loss of both OATP1B1 and OATP1B3 function is the underlying cause of Rotor syndrome, a rare condition characterized by chronic conjugated hyperbilirubinemia (J. Clin. Invest., 2012).

Other names

SLCO1B1SLCO1B3SLC21A6SLC21A8OATP-COATP-8LST-1LST-2OATP2Liver-specific organic anion transporter 1Liver-specific organic anion transporter 2

These transporters facilitate the sodium-independent uptake of organic anions from the sinusoidal blood into hepatocytes, likely operating as anion exchangers using intracellular bicarbonate or glutathione as counter-ions (Semanticscholar, 2023; NIH, 2026).