Inorganic anions and the renal organic cation transport system.

During renal secretion, organic cations (OC) have to pass two hydrophobic membranes (basolateral and luminal) and the intervening aqueous cytoplasm. Furthermore, an uptake in intracellular endosomes may also occur. OC transport critically depends on the presence or absence of certain inorganic anions, such as Cl-, HCO3-, and others. The interaction between inorganic anions and OC may occur during the transport across the membranes or uptake by endosomes, by alterations of the transport protein or the substrate and by changes of the intracellular pH.