Endotoxin-induced alterations in glucose transport in isolated adipocytes.
2-Deoxyglucose and 3-O-methylglucose were used to assess endotoxin-induced changes in glucose transport in rat adipocytes. 6 h after Escherichia coli endotoxin injection insulin-stimulated 2-deoxyglucose uptake was significantly depressed (V decreased, Km unaltered), phosphorylation of 2-deoxyglucose was seemingly unimpaired; basal 3-methylglucose entry was significantly increased, insulin-stimulated uptake was unaltered. Insulin significantly reduced Km in control and endotoxin-treated cells. Cytochalasin B-insensitive uptake of both 2-deoxy-glucose and 3-methylglucose, a small fraction of total transport, increased significantly in endotoxic cells. Endotoxin reduced spermine- and insulin-stimulated 2-deoxyglucose uptake to a similar extent. Results are consistent with the hypotheses that (1) a site of endotoxin-induced insulin resistance is at the cell membrane level and may reflect a decrease in number of activity of effective carrier units, rather than alterations in affinity, (2) endotoxin does not compromise the hexokinase system, (3) the cell membrane-localized effect of endotoxin on hexose transport is not necessarily mediated by the insulin receptor and (4) the entry of 2-deoxyglucose and 3-methyl-glucose may involve two separate transport systems.
D019325:3-O-Methylglucose; D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D003571:Cytochalasin B / Q000494:pharmacology; D003837:Deoxy Sugars / Q000378:metabolism*; D003847:Deoxyglucose / Q000378:metabolism*; D004731:Endotoxins / Q000494:pharmacology*; D004926:Escherichia coli; D007328:Insulin / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D008757:Methylglucosides / Q000378:metabolism*; D008759:Methylglycosides / Q000378:metabolism*; D010766:Phosphorylation; D051381:Rats; D011919:Rats, Inbred Strains; D013096:Spermine / Q000494:pharmacology
D003837:Deoxy Sugars; D004731:Endotoxins; D007328:Insulin; D008757:Methylglucosides; D008759:Methylglycosides; D019325:3-O-Methylglucose; D013096:Spermine; D003571:Cytochalasin B; D003847:Deoxyglucose