RECOVERY POTENTIAL IN GLUCOSE DEPRIVED ASTROCYTES

D-glucose deprivation for a 45 min period reduces the ATP and creatine phosphate concentrations of astrocytes. Recovery experiments were ini tiated by reincubating the cells with D-glucose and glucose replacemen t metabolites. No recovery of ATP concentration could be obtained even after 1 h of reincubation with the replacement metabolites. After a 4 5 min incubation period without D-glucose, (CO2)-C-14 production fell to 36% and 21% of controls when the cells were reincubated respectivel y with D-[U-C-14]-glucose and L-[2-C-14]-pyruvate as substrate marker. When reincubated for 1 h in the presence of L-malate (1 mM) + L-pyruv ate (10 mM) with L-[2-C-14]-pyruvate as marker, a total recovery of (C O2)-C-14, production was ascertained. Reincubation of the glucose depr ived cells in the presence of D-glucose (10 mM) did not increase the ( CO2)-C-14 production indicating that the cells were unable to use D-gl ucose for oxidative purposes. As pyruvate concentration was dramatical ly decreased in glucose deprived cells, astrocytes were treated with a lpha-ketovalerate (25 mM) which led to an 8-fold increase in pyruvate concentration. In these conditions (CO2)-C-14 production did not incre ase when the cells were incubated in the presence of L-malate (1 mM). O-2 consumption of State 4 in astrocytes, submitted to glucose depriva tion, decreased. These cells treated with FCCP could not be uncoupled and when reincubated in the presence of replacement metabolites only a 20% increase of oxygen consumption took place.