Modifications induced by diabetes on the physicochemical and functional properties of erythrocyte plasma membrane

Abstract

Abstract. Increasing evidence suggests that in experimental diabetes an impairment in Na+, K+–ATPase activity plays a central role in the pathophysiology of diabetic complications, while only a few data are available with regard to human subjects. We studied the erythrocyte membrane Na+, K+‐ATPase activity and membrane fluidity in insulin‐dependent and non‐insulin‐dependent diabetic subjects. A significant decrease in the enzyme activity and in fluorescence polarization values was found in both groups compared with normal subjects. Neither Na+, K+‐ATPase activity nor membrane fluidity was found to be related to metabolic control, assessed by means of fasting blood glucose levels and HbA1c. On the contrary, a significant correlation was observed between Na+, K+‐ATPase activity and membrane fluidity in both insulin‐dependent and non‐insulin‐dependent diabetic subjects. The present work provides evidence that a reduction in the Na+, K+‐ATPase activity is present in the plasma membranes of insulin‐dependent and non‐insulin‐dependent diabetics. Furthermore, it suggests that the change in enzyme activity might be related to modifications in membrane fluidity.