Solute carrier organic anion transporter family member 1B1 (OATP1B1) and Solute carrier organic anion transporter family member 1B3 (OATP1B3) (OATP1B1 and OATP1B3)

Solute carrier organic anion transporter family member 1B1 (OATP1B1) and 1B3 (OATP1B3) are key multispecific uptake transporters expressed on the sinusoidal membrane of human hepatocytes (UniProt Q9Y6L6, Q9NPD5). They play a crucial role in the hepatic clearance of a wide range of endogenous substances, including bilirubin, bile acids, and hormones, as well as numerous clinically important drugs such as statins, ACE inhibitors, and certain antibiotics (PubMed: 23588310). By facilitating the entry of these compounds from the blood into the liver, they determine the systemic exposure and intrahepatic concentration of their substrates. Genetic variations in the SLCO1B1 gene, particularly the c.521T>C polymorphism, are associated with significantly reduced transport activity, leading to increased plasma levels of drugs like simvastatin and an elevated risk of adverse effects such as myopathy (StatPearls: Statin Toxicity). Furthermore, OATP1B1 and OATP1B3 are major sites for drug-drug interactions; inhibition of these transporters by co-administered drugs like cyclosporine can lead to profound changes in the pharmacokinetics of substrate drugs, necessitating careful evaluation during drug development (FDA: Drug-Drug Interaction Guidance). These transporters are often evaluated together in regulatory submissions due to their overlapping substrate specificity and shared localization. Endogenous biomarkers like coproporphyrin I are increasingly used to monitor their function in vivo (PubMed: 28214524).

Other names

SLCO1B1SLCO1B3OATP-COATP-8LST-1LST-2OATP2OATP1B1/1B3

Facilitated sodium-independent transport of organic anions into hepatocytes; drugs act as substrates for hepatic clearance or as inhibitors leading to increased systemic exposure of co-administered substrates (PubMed: 21383205).