SLCO1B1, also known as Solute Carrier Organic Anion Transporter Family Member 1B1, is a membrane-bound transporter protein predominantly found in the liver. It plays a crucial role in the uptake of various endogenous and exogenous compounds — including bile acids, hormones, medications, and toxins — from the bloodstream into liver cells (hepatocytes). One of its primary functions is to facilitate the hepatic uptake of bile acids, which is vital for maintaining bile acid balance and bile production. By transporting bile acids across the sinusoidal membrane of hepatocytes, SLCO1B1 aids their removal from the blood and incorporation into bile.