Erythrocyte membrane glycation and NA⁺–K⁺ levels in NIDDM

Abstract 

Although there are many investigations on protein glycation in diabetic patients, many detailed studies are needed on this subject. In this study, the correlation between red cell membrane and serum protein glycation was investigated in NIDDM. The relation of membrane glycation to intracellular Na⁺ and K⁺ levels was also considered. Forty patients with NIDDM and 22 healthy subjects were included in the study. The membrane proteins were isolated, and total protein (TP_m) and fructosamine (FA_m) levels were determined. Serum glucose, fructosamine (FA_s) and total protein (TP_s) levels were also measured. HbA_1C, red blood cell (RBC) and reticulocyte (RET) counts in whole blood were made in all samples. NA⁺ and K⁺ levels of both serum and RBC were determined. The patient group had lower levels of K⁺_RBC (P<.001) and Na⁺_s (P<.05) and RBC count (P<.05), and higher levels of FA_m (P<.001), Na⁺_RBC (P<.01), K⁺_s (P<.01), glucose (P<.001) and HbA_1C (P<.001) than those of controls. The ratios of FA_s/TP_s (P<.001) and FA_m/TP_m (P<.001) were higher in patients than in control. As a result, HbA_1C levels and the ratio of FA_m/TP_m were high in NIDDM patients (P<.001) and these patients have slight negative correlations in FA_m/TP_m and FA_s/TP_s (P<.05). On the other hand, that there is no correlation between RBC membrane protein glycation and RBC Na⁺ and K⁺ levels may be caused by the fact that the membrane protein glycation is lower than that of other soluble proteins and that the membrane proteins are functional with respect to Na⁺–K⁺ transport.

Keywords:  Diabetes, Erythrocytes, Protein glycation, Na⁺, K⁺