[Erythrocyte ion transport and membrane potential in patients with chronic kidney failure]

The membrane potential (delta E), the K+ concentration and the Ca2+-dependent potassium permeability of erythrocytes were studied in patients suffering from chronic renal insufficiency (CRI) in the terminal stage and undergoing hemodialysis. Increased absolute delta E value and reduced K+ concentration in the erythrocytes were revealed during the pathological condition. When erythrocytes were de-energized by NaF, addition of Ca2+ led to K+ elimination and proton rebound due to calcium-hydrogen exchange through the membrane. In some cases repeated injections of Ca2+ caused a series of rebounds, potassium penetration diminished in such instances. The proton rebound was absent in almost half of the patients with chronic renal insufficiency and the potassium flow was inhibited. The mechanisms of delta E increase are discussed and it is suggested that the inhibition of Ca2+-induced potassium penetration is due to structural changes of the erythrocyte membranes in CRI.