ENERGY-METABOLISM IN HYPOXIC ASTROCYTES - PROTECTIVE MECHANISM OF FRUCTOSE-1,6-BISPHOSPHATE

The protective effects of fructose-1,6-biphosphate (FBP) during hypoxi a/ischemia are thought to result from uptake and utilization of FBP as a substrate for glycolysis or from stimulation of glucose metabolism. To test these hypotheses, we measured CO2 and lactate production from [6-C-14]glucose, [1-C-14]glucose, and [U-C-14]FBP in normoxic and hyp oxic cultured astrocytes with and without FBP present. FBP had little effect on CO2 production by glycolysis, but increased CO2 production b y the pentose phosphate pathway. Labeled FBP produced very small amoun ts of CO2. Lactate production from [1-, and 6-C-14]glucose increased s imilarly during hypoxic hypoxia; the increase was independent of added FBP. Labeled lactate from [U-C-14]FBP was minimal. We conclude that e xogenous FBP is not used by astrocytes as a substrate for glycolysis a nd that FBP alters glucose metabolism.