Functional expression of the renal organic cation transporter and P-glycoprotein in Xenopus laevis oocytes

Cancer Chemother Pharmacol. 1995;37(1-2):187-9. doi: 10.1007/BF00685648.


The hypothesis that P-glycoprotein (P-gp) mediates the renal secretion of organic cations was tested by functional expression of mRNAs in the Xenopus laevis oocyte system. Efflux of 2'-deoxytubercidin (dTub), a substrate for the renal organic cation transporter (OCT) but not for P-gp, was enhanced by injection of renal mRNA but not by injection of mRNA from P-gp-overexpressing cells (MDCK cells transduced with the cDNA for human MDR1). The functional capacity of the MDCK-MDR mRNA was established by its ability to reduce the steady-state uptake of a classical P-gp substrate, vinblastine. Thus, these data indicate OCT and P-gp to be distinct entities. The Xenopus oocyte system provides a functional approach to further characterize the OCT.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B, Member 1 / biosynthesis*
  • Animals
  • Biological Transport
  • Carrier Proteins / biosynthesis*
  • Cations / metabolism
  • Female
  • Humans
  • Ion Transport
  • Kidney / metabolism*
  • Mice
  • Oocytes / metabolism*
  • RNA, Messenger / analysis
  • Swine
  • Tubercidin / analogs & derivatives
  • Tubercidin / metabolism
  • Xenopus laevis


  • ATP Binding Cassette Transporter, Subfamily B, Member 1
  • Carrier Proteins
  • Cations
  • RNA, Messenger
  • 2'-deoxytubercidin
  • Tubercidin