Figure 1.

Tissue-dependent expression of the major OATs and OATPs implicated in drug therapy. The OATs and OATPs facilitate the directional movement of various endogenous and xenobiotic substrates, including clinically used drugs. Genetic and epigenetic controls coordinate the tissue-dependent expression profiles of these transporters. The OATs and OATPs play important roles in the hepatobiliary transport, renal secretion, intestinal absorption, and blood-brain barrier function by working with the ABC transporters.