Calcium-dependent stimulation of 3-O-methylglucose uptake in rat thymocytes by the divalent cation ionophore A23187.
A23187 (0.2 TO 1.0 Nmol/mg of cell protein) stimulates the transport of 3-O-methylglucose by rat thymocytes more than 2-fold within 10 min in the presence of 1.9 mM Ca2+. Under these conditions, Ca2+ uptake by the cells increases 3- to 10-fold. The ionophore is less effective at lower Ca2+ concentrations and it has no effect on 3-O-methylglucose uptake when ethylene glycol bis(beta-aminoethyl ether)-N,N'-tetraacetate (EGTA) is present in excess over Ca2+. Excess EGTA does not reduce the elevated rates of 3-O-methylglucose transport in cells already stimulated with A23187 on 3-O-methylglucose transport is completely blocked by inhibitors of oxidative phosphorylation. The results suggest that elevated cytoplasmic Ca2+ concentrations activate some ATP-dependent mechanism that modifies the glucose transport system in a manner that is not readily reversible.
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001692:Biological Transport; D000001:Calcimycin / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology*; D004533:Egtazic Acid / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008757:Methylglucosides / Q000378:metabolism*; D008759:Methylglycosides / Q000378:metabolism*; D051381:Rats; D013950:Thymus Gland / Q000187:drug effects / Q000378:metabolism*; D014475:Uncoupling Agents / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D008757:Methylglucosides; D008759:Methylglycosides; D014475:Uncoupling Agents; D000001:Calcimycin; D004533:Egtazic Acid; D002118:Calcium