Organic cation transporters are members of the SLC22A superfamily. These transporters are polyspecific and are involved in the absorption and excretion of various endogenous and exogenous compounds¹. The family consists of 18 genes and includes the organic cation transporters (OCTs), organic cation/carnitine transporters (OCTNs), and organic anion transporters (OATs)^1-3.

Most family members share a common membrane topology consisting of a predicted 12 α-helical transmembrane domains and two hydrophilic loops^2,4. Although they share a common structure, the transporters in the SLC22A family show differential tissue distribution. The genes encoding the three organic cation transporters (SLC22A1-3) are all located in a cluster on chromosome 6^2-4.

Organic cation transporter 2 (OCT2) was first identified in the rat in 1996. It is primarily located on the basolateral surface of renal proximal tubules, particularly on the S2 and S3 segments and also expressed in brain.

OCT2 mediates the uptake from circulation of several endogenous compounds like creatinine, choline and norepinephrine and also exogenous ones, that include commonly prescribed drugs like the antineoplastic drug cisplatin and the antidiabetic Metformin ^5,6.