Differential localization of organic cation transporters rOCT1 and rOCT2 in the basolateral membrane of rat kidney proximal tubules

Histochem Cell Biol. 2000 Sep;114(3):175-80. doi: 10.1007/s004180000186.


Organic cation transporters play an important role in the secretion of cationic drugs as well as endogenous cationic metabolites in the renal tubules. Immunoblotting showed the presence of organic cation transporter proteins, rOCT1 and rOCT2, in the rat kidney. By immunofluorescence microscopy, rOCT1 was shown to be concentrated in the proximal tubules in the renal cortex. rOCT2, on the other hand, was rich in the proximal tubules in the outer stripe of the outer medulla. Confocal microscopy revealed that both rOCT1 and rOCT2 were localized to the basolateral membranes of these tubule cells. These findings directly show that rOCT1 and rOCT2 are basolateral membrane proteins and are differentially distributed along the proximal tubules.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carrier Proteins / analysis*
  • Cell Membrane / chemistry
  • Cell Membrane / ultrastructure
  • Immunoblotting
  • Immunohistochemistry / methods
  • Kidney Cortex / cytology*
  • Kidney Tubules, Proximal / chemistry
  • Kidney Tubules, Proximal / cytology*
  • Male
  • Membrane Proteins / analysis*
  • Microscopy, Confocal / methods
  • Microscopy, Fluorescence / methods
  • Organic Cation Transport Proteins*
  • Organic Cation Transporter 1
  • Organic Cation Transporter 2
  • Rats
  • Rats, Wistar


  • Carrier Proteins
  • Membrane Proteins
  • Organic Cation Transport Proteins
  • Organic Cation Transporter 1
  • Organic Cation Transporter 2
  • Slc22a2 protein, rat