Solute carrier family 23 member 3
hypoxanthine transport
SLC23A3 is a renal hypoxanthine transporter.
LLC-PK1 renal cells show Na<sup>+</sup>-dependent and Na<sup>+</sup>-independent hypoxanthine uptake. While the latter is inhibited by adenine, neither are inhibited by xanthine. In rats, intestinal Na<sup>+</sup>-dependent hypoxanthine transporter Slc23a4 is not expressed in the kidney, and its action is inhibited by xanthine. This study aimed to clone <i>Slc23a4</i>-paralog <i>SLC23A3</i> from the human kidney and investigate its hypoxanthine transport activity. We observed Na<sup>+</sup>-dependent 10 nM [<sup>3</sup>H]-hypoxanthine uptake in <i>SLC23A3</i> RNA-injected <i>Xenopus</i> oocytes. Moreover, 100 μM xanthine did not inhibit Na<sup>+</sup>-independent 300 nM [<sup>3</sup>H]-hypoxanthine uptake, whereas 100 μM adenine did. These results confirm that SLC23A3 is a hypoxanthine transporter in the human kidney.