Augmentation of ouabain sensitivity of rat liver Na/K-ATPase by in vivo adenovirus-mediated expression of the Na/K-ATPase alpha2 subunit.
These are the first experiments to study the effect of in vivo expression of the Na/K-ATPase alpha2 subunit which serves as a receptor for cardiac glycosides. The alpha2 subunit is not normally expressed in rat liver, so hepatocytes which lack endogenous alpha2 protein are a logical first target to study the effects of alpha2 expression on membrane Na/K-ATPase activity. At 3 days after alpha2 adenovirus vector infusion, Wistar rat livers contained alpha2 DNA, alpha2 mRNA, and alpha2 protein. Rat liver membrane ouabain binding activity and the sensitivity of Na/K-ATPase activity to ouabain significantly increased. Total membrane Na/K-ATPase was regulated at a constant level while expressed alpha2 activity represented 10% of the total active Na/K-ATPase sites in alpha2 transduced rat liver. These studies are the first to establish a paradigm in which an endogenous drug receptor is expressed to alter cellular pharmacologic sensitivity.
Askari
F K
FK
Department of Internal Medicine, University of Michigan, Ann Arbor 48109, USA. FASKARI@medmail-med.umich.edu
Hitomi
Y
Y
Xie
Z
Z
D000260:Adenoviruses, Human / Q000235:genetics*; D000818:Animals; D002461:Cell Line, Transformed; D002462:Cell Membrane / Q000378:metabolism; D004279:DNA, Viral / Q000032:analysis; D005822:Genetic Vectors; D006367:HeLa Cells; D006801:Humans; D015151:Immunoblotting; D007262:Infusions, Intravenous; D007275:Injections, Intravenous; D008099:Liver / Q000378:metabolism*; D010042:Ouabain / Q000378:metabolism* / Q000494:pharmacology; D012367:RNA, Viral / Q000032:analysis; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D011955:Receptors, Drug / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics / Q000378:metabolism*; D014170:Transformation, Genetic
D004279:DNA, Viral; D012367:RNA, Viral; D011955:Receptors, Drug; D011993:Recombinant Fusion Proteins; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase