Niske molekularne koncentracije ouabaina potiču veću aktivnost Na+/K+-ATPaze u čovječjim eritrocitima.

The inhibitor g-Strophantin, also known as ouabain, is a specific inhibitor of the Na+/K+-ATPase. In this work ouabain has been used for the inhibition of the Na+/K+-ATPase in human erythrocytes and isolated enzyme from pig kidney. Enzymatic activity of the Na+/K+-ATPase has been measured in a broad concentration range of ouabain in two different in vitro investigations. As a potent inhibitor of the sodium pump the cardiotonic steroid ouabain inhibits its enzymatic activity on both isolated human red blood cells and on the purified enzyme from pig kidney. Na+/K+-ATPase activity in erythrocyte can be determined by measuring the ouabain-sensitive uptake of 86Rb (as a congener for potassium). This work provides evidence that very low concentrations of ouabain in the nM range can stimulate increase of Na+/K+-ATPase activity in human erythrocytes, in contrast to inhibition of the purified enzyme from pig kidney, where such an effect was not observed.g-Strophantin koji je poznat i pod imenom ouabain je specifični inhibitor Na+/K+-ATPase. U ovom je radu ouabain korišten u inhibiciji enzimske aktivnosti Na+/K+-ATPase u čovječjim eritrocitima i izoliranom enzimu iz bubrega svinje. Kao jaki inhibitor natrijeve pumpe kardiotoni steroid, ouabain inhibira njenu aktivnost u oba slučaja u izoliranim čovječjim eritrocitima i pročišćenom enzimu. Aktivnost Na+/K+-ATPase u eritrocitima može biti proučavana koristeći se modelom aktivnog unosa radioaktivnog rubidija (86Rb) kao analoga kalija u samu stanicu. Ovaj rad prikazuje da vrlo niske nano-molarne koncentracije ouabaina mogu potaknuti povećanje enzimske aktivnosti Na+/K+-ATPase u čovječjim eritrocitima u usporedbi s izoliranim enzimom u kojeg taj učinak nije primijećen