The proteins OCT1 and OCT2 are directly involved in the absorption and excretion processes of food components and xenobiotic compounds in the liver, small intestine and kidney, as well as activity in other tissues such as brain, heart, stomach and skeletal muscle. The Oct1/2 Targeted Mutation mouse is available for use in various ADME-Tox research applications. OCT1 and OCT2 are members of the solute carrier family 22 (organic cation transporter). These proteins are located on the surface of epithelial cells in the liver, intestine, and kidney. Because these transporters control the renal secretion of small organic cations, they are thought to play an essential role in removing toxins from the body. In humans, OCT1 is primarily expressed in the liver, and OCT2 is expressed primarily in the kidneys. However, in rodents, OCT1 is primarily expressed in the liver, small intestine, and kidney, with some expression in the brain, heart, stomach, and skeletal muscle. Rodent OCT2 is expressed mainly in the kidneys, as in humans, however it is also expressed in the small intestine, liver, and brain.