Cerebral glucose utilization and glucose transporter expression: Response to water deprivation and restoration

The relationship between local rates of cerebral glucose utilization (lCMR( glc)) and glucose transporter expression was examined during physiologic ac tivation of the hypothalamoneurohypophysial system. Three days of water dep rivation, which is known to activate the hypnthalamoneurohypophysial system , resulted in increased lCMR(glc) and increased concentrations of GLUT1 and GLUT3 in the neurohypophysis; mRNA levels of GLUT1 and GLUT3 were decrease d and increased, respectively. Water deprivation also increased lCMR(glc) i n the hypothalamic supraoptic and paraventricular nuclei; mRNA levels of GL UT1 and GLUT3 appeared to increase in these nuclei, but the changes did not achieve statistical significance. Restoration of water for 3 to 7 days rev ersed all observed changes in GLUT expression (protein and mRNA); restorati on of water also reversed changes in lCMR(glc) in both the neurohypophysis and the hypothalamic nuclei. These results indicate that under conditions o f neural activation and recovery, changes in lCMR(glc) and the levels of GL UT1 and GLUT3 an temporally correlated in the neurohypophysis and raise the possibility that GLUT1 and GLUT3 transporter expression may be regulated b y chronic changes in functional activity. In addition, increases in the exp ression of GLUT5 mRNA in the neurohypophysis after dehydration provide evid ence for involvement of microglial activation.