Effect of acute hyperglycemia on potassium (Rb-86(+)) permeability and plasma lipid peroxidation in subjects with normal glucose tolerance

Hyperglycemia is likely to be one of the important determinants of ion tran sport as it is known to induce oxidative stress and may thus enhance non-sp ecific permeability of membranes. The aim of the present study was to evalu ate the effects of an acute increase in glycemia on Rb-86(+) (a marker for K+) influx and lipid peroxidation. We evaluated the 75-g oral glucose toler ance test (OGTT)-induced modification on Rb-86(+) influx and plasma lipid p eroxidation in 20 subjects with normal glucose tolerance (NGT). After 2-hou r glucose loading, the levels of passive Rb-86(+) influx and plasma lipid p eroxidation were significantly increased, whereas the active influx of Rb-8 6(+) was unchanged. The total and passive influx of Rb-86(+) into erythrocy tes was significantly correlated with the level of plasma lipid peroxidatio n. This study demonstrates that acute hyperglycemia induces an increase in the passive influx of Rb-86(+) in subjects with NGT, suggesting that acute hyperglycemia may produce an oxidative stress in plasma. These changes may be among the earliest changes occurring in response to hyperglycemia. ((C)) 2001, Editrice Kurtis.