Immunohistochemical localization of sodium-dependent L-ascorbic acid transporter 1 protein in rat kidney.

Recently, two L-ascorbic acid transporters were identified; sodium-dependent vitamin C transporter (SVCT) 1 and SVCT2. The previous study suggested that SVCT protein might be present on the apical membrane in the straight segment (S3) of proximal tubule. In the present study, SVCT1 immunoreactivity (IR) was observed in the brush border of proximal straight tubules in the medullary ray of renal cortex and the outer stripe of outer medulla, while SVCT2 IR was not localized in any region of the kidney. Since the mechanism of VC reabsorption in the kidney has not been fully elucidated up to the present time, it is meaningful to demonstrate the exact cellular distribution of SVCT protein in the kidney.