SLCO1B1, also known as Solute Carrier Organic Anion Transporter Family Member 1B1, is a membrane-bound transporter protein primarily located in the liver. It plays a key role in the uptake of various endogenous and exogenous compounds — including bile acids, hormones, drugs, and toxins — from the bloodstream into liver cells (hepatocytes). One of its main functions is facilitating the hepatic uptake of bile acids, which is essential for maintaining bile acid balance and bile production. By transporting bile acids across the sinusoidal membrane of hepatocytes, SLCO1B1 supports their clearance from the blood and incorporation into bile.