Mechanisms of ouabain resistance

Experiments were designed to investigate the mechanism of ouabain resistance in two distinct types of transfected cells derived from ouabain-sensitive CV-1 cell parents. The first type of transfectant is the recipient of a gene encoding the alpha subunit of the rodent renal Na,K-ATPase (R-alphal gene); the second type of transfectant is the recipient of the mouse ouabain resistance gene. Measurements of 86Rb+ uptake and Na,K=ATPase activity in R-alphal gene transfectant cells and CV-1 parent cells indicate that the ouabain-resistant phenotype of the transfectants is due to expression of a relatively ouabain-insensitive Na,K=ATPase. CV-1 parent cells express one component of ouabain sensitive 86Rb+ uptake and one component of ouabain-sensitive Na, K-ATPase activity. R-alpha 1 gene transfectants express the parental forms of ouabain-sensitive 86Rb+ uptake and Na,K-ATPase activity, but in addition express new,relatively ouabain-insensitive forms of 86Rb+ uptake activity and Na,K-ATPase activity