Facilitated transport of 3-O -methyl-D-glucose in human polymorphonuclear leukocytes

Abstract

Transport of the nonmetabolizable hexose analogue 3-O-methyl-D-glucose (3OMG) was measured in human polymorphonuclear leukocytes at 37° pH 7.4. 30MG at very low concentration (0.05 mM) equilibrated with the intracellular water with a rate constant of about 0.08 s⁻¹. Transport of 3OMG in the presence of 20 μM cytochalasin B and transport of L-glucose were insignificant. Countertransport of ¹⁴C-labelled 3OMG was demonstrated. Exchange of 3OMG between the extracellular and intracellular water showed saturation with a K _m of about 4 mM. Thus, the transport of 3OMG is mediated almost exclusively by facilitated diffusion.