Effect of chemotactic factors on hexose transport in polymorphonuclear leucocytes.
Transport of the nonmetabolizable glucose analogue, 3-O-methylglucose, was assessed in human polymorphonuclear leucocytes with or without the chemotactic peptide N-formylmethionylleucylphenylalanine (fMet-Leu-Phe). The peptide increased entry of labelled 3-O-methylglucose about 5-fold and the intracellular distribution space about 70%. The half-time of equilibration was 3 s in the treated cells. Similar effects were observed with zymosan-treated serum (containing the chemotactic factor C5a), with arachidonic acid, calcium ionophore A23187 and phorbol myristate acetate. However, the chemotactic protein, thrombin, had no effect, even though binding to high-affinity receptors was demonstrated. Km for zero-trans entry of 3-O-methylglucose was about 1 mM and fMet-Leu-Phe increased Vmax from 5 to about 25 amol.s-1.cell-1. Similar values were obtained from incubations for a few seconds with glucose and 2-deoxyglucose. The rate of 2-deoxyglucose uptake (8 min incubations) was limited by the transport step at substrate concentrations lower than approx. 0.1 mM, whereas the phosphorylation step became rate-limiting at higher concentrations. Thus, 2-deoxyglucose uptake can only be taken as a measure of transport at a tracer concentration. It is concluded that chemotactic factors can, but do not necessarily, increase the maximal transport velocity of hexoses entering the polymorphonuclear leucocyte via the glucose transporter.
D019325:3-O-Methylglucose; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D001769:Blood; D000001:Calcimycin / Q000494:pharmacology; D002630:Chemotactic Factors / Q000494:pharmacology*; D003847:Deoxyglucose / Q000097:blood; D005947:Glucose / Q000378:metabolism; D006601:Hexoses / Q000097:blood*; D006801:Humans; D007700:Kinetics; D008757:Methylglucosides / Q000097:blood; D009004:Monosaccharide Transport Proteins / Q000097:blood; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013917:Thrombin / Q000494:pharmacology; D015054:Zymosan / Q000494:pharmacology
D001095:Arachidonic Acids; D002630:Chemotactic Factors; D006601:Hexoses; D008757:Methylglucosides; D009004:Monosaccharide Transport Proteins; D019325:3-O-Methylglucose; D016718:Arachidonic Acid; D000001:Calcimycin; D009240:N-Formylmethionine Leucyl-Phenylalanine; D015054:Zymosan; D003847:Deoxyglucose; D013917:Thrombin; D005947:Glucose; D013755:Tetradecanoylphorbol Acetate