title: Mechanism of mitogen-induced stimulation of glucose transport in human peripheral blood mononuclear cells. Evidence of an intracellular reserve pool of glucose carriers and their recruitment.
abstract: The present study examines the effects of phytohemagglutinin stimulation of a population of human (h) PBMC enriched in lymphocytes (hPBMC) on D-glucose displaceable cytochalasin B binding sites or medium-affinity sites (M-sites) in relation to glucose transport. Previously we have shown that M-sites are glucose transporters in hPBMC (Mookerjee, B.K., et al. 1981. J. Biol. Chem. 256:1290-1300). Equilibrium exchange of 3-O-methyl D-glucose in unstimulated cells revealed two populations with fast and slow flux rates. Phytohemagglutinin stimulates flux rates by converting part of the slow flux population to the fast flux population. M-sites occur in two distinct pools, one in plasma membrane and the other in microsomal fraction. Phytohemagglutinin treatment increases the plasma membrane pool size of M-sites with a concomitant reduction in the microsomal pool size without affecting the binding affinities or the total number of M-sites/cell. Data presented in this paper demonstrate that there are two pools of glucose transporters in these cells and phytohemagglutinin stimulation induces an energy-dependent net translocation of glucose transporters from an intracellular reserve pool to the plasma membrane, which accounts for greater than 60% of the increment in glucose transport.
authors.affiliation: Department of Medicine, Veterans Administration Medical Center, Buffalo, New York 14215.
authors.forename: D B
authors.initials: DB
authors.lastname: Jacobs
authors.forename: T P
authors.initials: TP
authors.lastname: Lee
authors.forename: C Y
authors.initials: CY
authors.lastname: Jung
authors.forename: B K
authors.initials: BK
authors.lastname: Mookerjee
mesh_terms: D019325:3-O-Methylglucose; D003571:Cytochalasin B / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D007700:Kinetics; D008757:Methylglucosides / Q000097:blood; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D009504:Neutrophils / Q000378:metabolism*; D010835:Phytohemagglutinins / Q000494:pharmacology; D011190:Potassium Cyanide / Q000494:pharmacology; D013696:Temperature; D013997:Time Factors
chemical_list: D007328:Insulin; D008757:Methylglucosides; D009004:Monosaccharide Transport Proteins; D010835:Phytohemagglutinins; D019325:3-O-Methylglucose; D003571:Cytochalasin B; D011190:Potassium Cyanide