Functional expression of the renal organic cation transporter and P-glycoprotein in Xenopus laevis oocytes.
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.
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis*; D000818:Animals; D001692:Biological Transport; D002352:Carrier Proteins / Q000096:biosynthesis*; D002412:Cations / Q000378:metabolism; D005260:Female; D006801:Humans; D017136:Ion Transport; D007668:Kidney / Q000378:metabolism*; D051379:Mice; D009865:Oocytes / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D013552:Swine; D014372:Tubercidin / Q000031:analogs & derivatives / Q000378:metabolism; D014982:Xenopus laevis
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D002352:Carrier Proteins; D002412:Cations; D012333:RNA, Messenger; C053222:2'-deoxytubercidin; D014372:Tubercidin