The effects of different a-D-Glucose (Glu) concentrations (0 -16 mᴍ) on Na+, K+-ATPase and Mg2+-ATPase activities were investigated in homogenates of adult male rat whole brain at 37 °C. The enzyme activities were determined after 1h preincubation with Glu. Brain Na+, K+-ATPase was not affected by Glu different concentrations. On the contrary, Mg2+-ATPase activity was considerably reduced with Glu concentrations lower than 4 mᴍ. The enzyme was inhibited 40%, 50% or 80% with 3, 2 or 1 mᴍ of Glu,

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... respectively. The above results suggest: a) The various concentrations of Glu have no effect on brain Na+, K+-ATPase activity, b) The inhibited brain Mg2+-ATPase in hypoglycemia produces low intracellular Mg2+, which could modulate the activity of Mg2+ -dependent enzymes and the rates of protein syn­thesis and growth of the cell.