Magnesium Sulfate Enhances Glucose Transporter-3

[[abstract]]Although our previous studies demonstrated that magnesium sulfate increased extracellular glucose levels during short-term forced swimming in gerbils, a complete understanding of the effects of magnesium sulfate on glucose levels remains unclear. The transport of glucose into most mammalian cells is mediated by a family of glucose transporter proteins. The brain type glucose transporter glucose transporter-3 (GLUT-3) is the predominant neuronal glucose transporter and contributes to the transport of glucose, the main source of energy for survival, into neuronal cells. In this study, we further evaluated the effects of magnesium sulfate on the levels of GLUT-3 protein expression, glucose, and magnesium in brain in gerbils that had been subjected to short-term forced swimming. Gerbils were separated into four groups: gerbils in group 1 (control group, C group) were only pretreated with saline, gerbils in group 2 (Mg group) were only pretreated with magnesium sulfate (90 mg•kg^(-1), ip), gerbils in group 3 (C+S group) were pretreated with saline before the 15 min forced swimming then rested for 30 min prior to sacrifice, gerbils in group 4 (Mg+S group) were pretreated with saline before the 15 min forced swimming then rested for 30 min prior to sacrifice. Data were obtained by western blotting assays, a microdialysis analyzer and a flame atomic absorption spectrometer. These results showed that pretreatment with magnesium sulfate (Mg group) significantly elevated GLUT-3 protein, glucose and magnesium levels in the cortex (p<0.01). Saline+short-term forced swimming (C+S group) had no significant effect on GLUT-3 protein, glucose and magnesium levels; however, the cortex GLUT-3 protein, glucose, and magnesium levels of the magnesium sulfate+swimming group (Mg+S) were higher than the C group (p