Structural specificity of hexose penetration of rabbit erythrocytes

The penetration of washed rabbit erythrocytes by deoxy and O-alkyl hexoses present at an initial concentration of 20 mm in a phosphate buffer saline solution was tested in vitro. Equilibration of hexoses with intracellular water was calculated from changes in hexose concentration in the medium during incubation. Analysis of cells plus medium indicated no utilization of deoxy and O-alkyl hexoses by red cells. Alterations in the structure of glucose at individual carbon atoms by the preparation of O-methyl and deoxy derivatives was found to have little effect on the permeability of the rabbit red cells to the molecule. The entrance of such compounds was found to be temperature dependent and all of the sugars tested compete with glucose for entrance. Increasing the chain length of the aliphatic substituent on carbon 3 of glucose from methyl to butyl greatly accelerates the rate of penetration. 3-Hydroxyethyl glucose showed the most rapid rate of equilibration with intracellular water of all of the glucose derivatives tested.