Non-Insulin Dependent Diabetic Patients have Increased Glucose Uptake in Red Blood Cells

Summary

The kinetic characteristics of 3-O-methyl glucose (3-OMG) uptake were examined in red blood cells (RBC) from seven normal individuals (controls) and nine patients with non-insulin-dependent diabetes mellitus (NIDDM) treated with diet and oral hypoglycemic medication. Comparison of rates of 3-OMG uptake at 5 different substrate concentrations revealed significantly higher overall 3-OMG uptake in the diabetic group (P < 0.0001). Kinetic parameters obtained for individual subjects showed there was not a significant difference in the K_m between the diabetic (3.17 ± 0.45 mM; mean ± SE) and the control (2.46 ± 0.25 mM) groups. However, V_max was significantly increased (61%; P < 0.025) in the diabetics (217.8 ± 28.9 pmol/2 sec per 10⁶ cells) compared to controls (135.2 ± 15.6 pmol/2 sec per 10⁶ cells). There was no correlation between HbA₁C levels in the diabetic patients and V_max values for 3-OMG uptake, suggesting that the increased hexose uptake was not accounted for simply by increased glycosylation in these cells. Glucose transport in RBC in hyperglycemic states may be a useful model for delineating the regulation of the non-insulin-mediated disposal of glucose in diabetes.

Key words

Diabetes - Glucose Uptake - Red Blood Cells - NIDDM