Glucose utilization in human erythrocytes during physical exercise.

Red blood cells obtained from well-trained athletes consumed glucose at a higher rate than those from sedentary subjects when incubated in vitro in a glucose containing medium at 37 degrees C. Similar results were obtained when fructose was substituted for glucose, but not when galactose was the monosaccharide. The utilization of glucose by erythrocytes can occur both via the Embden-Meyerhof and Pentose phosphate pathways (PPP). In the present experiments, there were no differences in the activities of select enzymes in these pathways or in metabolic intermediates of the erythrocytes. An exception was an elevated 2,3-diphosphoglycerate (2,3DPG) in the erythrocytes of the athletes. Additional experiments are needed to identify changes in the red blood cells of the athletes which produce the increased consumption of glucose.