[Isotope study of in vitro K(+) uptake and release of erythrocytes in juvenile diabetes with 86Rb].

In order to determine the reasons for a previously observed elevated intracellular Na+ and a decreased K+ level, the K+ uptake and release of the red blood cells in type I diabetics were examined with 86Rb. The K+ release and the ouabain-insensitive K+ uptake were different from those in the controls. Under the present experimental conditions, there was no decrease in ouabain-sensitive K+ uptake indicative of the activity of K+, Na(+)-ATPase. Likewise, an elevated activity normalizing a lower K+ level could not be detected. Further, there were no significant differences in the reaction kinetic parameters: KM[diab.]:4.21 +/- 1.38 mM/l, KM[contr.]:4.14 +/- 0.99 mM/l Vmax[diab.]:2259 +/- 326 nmol/ml red blood cell/hour Vmax[contr.]:2354 +/- 462 nmol/ml red blood cell/hour. These alterations are regarded as partial phenomena of the complex membrane function disturbances in diabetic red blood cells.