The Kinetics of Glucose Transport in Human Red Blood Cells Depend on Their Metabolic State

Abstract

This article about freshly drawn human red blood cells offers new insights in regulation of glucose transport. Transport of glucose in Glut1 red blood cells is highly asymmetric and depend on metabolic energy, most probably ATP. The changes in “Km” for efflux and Vm obtained by ATP depletion of the cells are completely restored by incubation with adenosine, a substrate for ATP generation. The glucose efflux in red cells is much higher than influx. The high amounts of the red cells in the blood (About 45%) provide by their efficient efflux system of more than 1000 mmol glucose/L cells/ min. support of glucose toward the peripherical cells as well as supply with oxygen. Wilbrandt’s general rate equation including osmometer behavior of the red blood cells and the solvation of the transport resistance with the individual parameters, including the turnover of the unloaded carrier is detailed mathematically explained. It is to memorize Walther Wilbrandt and a history of his contribution to the glucose transport in human red cells. The integrated rate equation describes perfectly the data obtained by right-angular light-scattering. Wilbrandt’s transport scheme can be used to calculate the turnover of the unloaded carrier. At 20°C a turnover of about 1000 molecules per sec. has been calculated, which might be interpreted as the oscillations of the empty carrier.