EFFECT OF EXPERIMENTAL DIABETES ON NA K-ATPASE ACTIVITY IN RED-BLOOD-CELLS, PERIPHERAL-NERVE AND KIDNEY/

A decrease in Na/K-ATPase activity is probably involved in the pathoge nesis of diabetic neuropathy. In human diabetes, Na/K-ATPase activity is almost always studied in red blood cells, readily accessible, and i t could represent a marker of predisposition to diabetic neuropathy. B ut, we wanted to establish whether diabetes induced similar changes of Na/K-ATPase activity in erythrocytes, and in other tissues, especiall y the peripheral nerve and the kidney. So, we compared Na/K-ATPase act ivity measured in the erythrocyte, sciatic nerve and kidney of rats wi th streptozotocin-induced diabetes after 8 weeks (n = 9) and normal fa ts (n = 9). Na/K-ATPase activity was 39-48 % lower in the RBC, sciatic nerve and kidney of diabetic rats compared to controls (RBC : 229 +/- 79 vs. 413 +/- 102 p <0.05; sciatic nerve : 3250 +/- 692 vs. 5532 +/- 1260 p 0.05; kidney: 12920 +/- 4010 vs. 22410 +/- 5310 p <0.05; resul ts in nmol Pi.mg protein-1.h-1; mean +/- SD). A signi ficant positive correlation was observed between Na/K-ATPase activities in the red blo od cells and sciatic nerve (r = 0.81, p<0.05) in the whole population of rats. This study shows that diabetes induces a parallel decrease in Na/K-ATPase activity in the red cell, sciatic nerve and kidney. The l evels of this enzyme activity are significantly correlated in the red cell and sciatic nerve so that diabetes-induced changes of Na/K-ATPase activity in the erythrocyte seem to reflect those in the peripheral n erve.