Unidirectional influx and phosphorylation of glucose analogues in cultured astroblasts.
Unidirectional influx of 14C-3OMG (3-O-methyl-D-glucose) and rate of phosphorylation of 14C-2DG (2-deoxy-D-glucose) were determined in primary cultures of astroblasts under conditions with negligible unstirred layers. The influx exhibited rate constants between 7.2 and 8.3 min-1 in the concentration range 2.5-25 mM of unlabeled 3OMG and was considered constant, irrespective of concentration of 3OMG. The rate of phosphorylation of 14C-2DG declined for rising concentrations of 2DG and hence showed saturability. The rate constants ranged from 7.9 to 0.1 min-1 in the concentration range 0.04-25 mM of 2DG. These results are not consistent with the view that the influx limits the rate of phosphorylation. They support the notion that the influx is not rate limiting for the phosphorylation.
D019325:3-O-Methylglucose; D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D003847:Deoxyglucose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D008757:Methylglucosides / Q000378:metabolism; D010766:Phosphorylation; D051381:Rats; D011919:Rats, Inbred Strains
D008757:Methylglucosides; D019325:3-O-Methylglucose; D003847:Deoxyglucose; D005947:Glucose