SLCO

Slco, commonly written SLCO, denotes the solute carrier organic anion transporter family of proteins, also known as organic anion transporting polypeptides (OATPs). Members encode membrane transporters that mediate uptake of a wide range of endogenous and exogenous organic anions across the cell membrane. The SLCO family is part of the SLC superfamily (SLC21) and comprises numerous human genes, including SLCO1B1, SLCO1B3, SLCO1A2, SLCO1C1, SLCO2B1, SLCO3A1, SLCO4A1, SLCO4C1, SLCO5A1, and SLCO6A1. Expression is tissue-specific, with high levels in liver, kidney, and intestine, and notable presence at the blood–brain barrier for some members.

Functionally, these are bidirectional, sodium-independent transporters that facilitate the uptake of a broad spectrum of substrates, including bile acids, bilirubin conjugates, hormones, and many drugs such as statins, antineoplastics, and antibiotics. They are typically localized on the basolateral membrane of hepatocytes and renal tubules, supporting hepatic and renal clearance and affecting the distribution of compounds throughout the body.

Clinical relevance includes genetic variation influencing drug pharmacokinetics and response. The SLCO1B1 c.521T>C (Val174Ala) variant reduces transporter activity and increases exposure to statins, particularly simvastatin, elevating the risk of myopathy. Drug–drug interactions are common, as inhibitors like rifampin can decrease hepatic uptake via OATPs. Defects in SLCO1B1 and SLCO1B3 are associated with Rotor syndrome, a hereditary conjugated hyperbilirubinemia.