Investigations on the existence of a specific retention of d-glucose by the human erythrocyte membrane

Abstract

1. 1. The retention of sugars by human erythrocyte membranes after incubation with different solutions containing a 3H- and a 14C-labelled sugar was compared by liquid scintillation counting, using a three-channel procedure with which it is possible to detect a change in the channel ratio of 3H and 14C of 0.2%. 2. 2. The retention of d-glucose by fragmented white ghost cell membranes did not differ from that of l-glucose or d-galactose. 3. 3. d-Glucose was taken up by intact pink ghost cells to a slightly greater extent than d-galactose at sugar concentrations of 1 mM or 40 mM. The increased uptake of d-glucose persisted after addition of HgCl 2 and phloretin in concentrations which block sugar transport. 4. 4. It is concluded that the retention of d-glucose by pink ghost cells does not bear any resemblance to the characteristics of the sugar transport system of the human erythrocyte as derived from kinetic data. The experiments thus do not support previous results in which it has been suggested that an interaction of d-glucose with the sugar transport system of human erythrocyte membranes is detectable in binding experiments.