Solute carrier family 22 member 1 (OCT1) and Solute carrier family 22 member 3 (OCT3) (OCT1 and OCT3)

Solute carrier family 22 member 1 (OCT1) and Solute carrier family 22 member 3 (OCT3) are polyspecific, sodium-independent transporters that facilitate the movement of organic cations across plasma membranes [4, 7, 12]. OCT1 is primarily localized to the sinusoidal membrane of hepatocytes, where it plays a critical role in the hepatic uptake and clearance of various drugs and endogenous compounds such as choline and thiamine [11, 14, 16]. OCT3, also known as the extraneuronal monoamine transporter (EMT), has a broader tissue distribution and is a key component of the "uptake-2" system, responsible for the clearance of monoamine neurotransmitters like dopamine, serotonin, and norepinephrine in the heart, brain, and other tissues [1, 3, 4]. These transporters are major determinants of the pharmacokinetics and therapeutic efficacy of several drugs, most notably the first-line antidiabetic agent metformin, which requires OCT1 for hepatic entry and OCT3 for systemic distribution [5, 15, 17]. Genetic polymorphisms in the SLC22A1 and SLC22A3 genes are associated with significant inter-individual variability in drug response and have been linked to the risk of type 2 diabetes, cardiovascular diseases, and certain cancers [14, 15, 18]. Furthermore, OCT1 and OCT3 are frequent sites of drug-drug interactions, as many clinical agents, including imatinib, verapamil, and various antidepressants, can inhibit their activity, potentially leading to altered drug exposure or toxicity [8, 9, 10, 12].

Other names

SLC22A1SLC22A3Organic cation transporter 1Organic cation transporter 3Extraneuronal monoamine transporterEMTHOCT1OCT1OCT3

Facilitated diffusion and polyspecific transport of organic cations across the plasma membrane