Organic anion transporter system (OATS)

The Organic anion transporter system is a specialized transport network located in the renal proximal tubules, primarily responsible for the active secretion of organic anions from the peritubular capillaries into the tubular lumen for excretion [1.1.1, 1.2.4]. This system is predominantly composed of the Organic Anion Transporter 1 (OAT1/SLC22A6) and Organic Anion Transporter 3 (OAT3/SLC22A8) proteins, which are located on the basolateral membrane and function as tertiary active transporters [1.2.1, 1.4.3]. These transporters facilitate the uptake of a diverse range of substrates—including endogenous metabolites like uremic toxins and exogenous substances such as antibiotics, antivirals, and diuretics—by exchanging them for intracellular dicarboxylates like alpha-ketoglutarate [1.2.1, 1.4.1]. The OAT system is a major determinant of the pharmacokinetics and renal clearance of many drugs, making it a frequent site of clinically significant drug-drug interactions [1.3.2, 1.5.2]. Pharmacological modulation of this system, such as through the use of the inhibitor probenecid, can be employed to reduce the renal clearance of certain drugs or to mitigate the nephrotoxicity of others by preventing their accumulation within tubular cells [1.5.1]. Dysfunction or reduced expression of these transporters is associated with the progression of chronic kidney disease and the accumulation of toxic metabolic byproducts [1.1.2, 1.5.5].

Other names

Renal organic anion secretion systemOAT systemSLC22 family transportersPara-aminohippurate transport systemOrganic anion transporter family

Competitive inhibition of basolateral organic anion transporters, specifically OAT1 and OAT3, which reduces the uptake of substrate drugs from the blood into renal tubular cells, thereby decreasing their renal secretion and increasing systemic exposure.