In Vivo Insulin Effect on ATPase Activities in Erythrocyte Membrane From Insulin-Dependent Diabetics

Na⁺-K⁺-dependent ouabain-sensitive ATPase and Mg²⁺-ATPase have been assayed in the erythrocyte membranes of control subjects and in uncontrolled type I (insulin-dependent) diabetics. A decrease in Na⁺-K⁺-ATPase activity was observed in the patients that was significantly correlated with glycemia. The Mg²⁺-ATPase was increased moderately, and no correlation with glycemia was found. To study the in vivo effect of insulin, ATPase activities were measured in uncontrolled diabetics before and after a 24-h continuous insulin perfusion administered by means of an artificial pancreas. ATPase activities were corrected after normalization of glycemia. It therefore seems that glycemia and/or insulinemia are involved in the regulation of erythrocyte Na⁺-K ⁺ ouabain-sensitive ATPase and to a lesser extent in that of Mg²⁺-dependent ATPase.