Activities of key glycolytic enzymes in the brains of patients with Alzheimer's disease

The activities of hexokinase, aldolase, pyruvate kinase, lactate dehydrogen ase and glucose 6-phosphate dehydrogenase were determined in brains of pati ents with Alzheimer's disease (AD) and in age matched controls. For pyruvat e kinase and lactate dehydrogenase a significant increase in specific activ ity was found in frontal and temporal cortex of AD brains, while the activi ties of aldolase and hexokinase are not changed. Glucose 6-phosphate dehydr ogenase activity was significantly reduced in hippocampus. The increase of some glycolytic enzyme activities is correlated with increased contents of lactate dehydrogenase and glial fibrillary acidic protein (GFAP) in homogen ates of frontal and temporal cortex and elevated phosphofructokinase (PFK) and GFAP in astrocytes from the same brain areas. The data extend previous findings on an increase in brain PFK specific activity in AD and suggest th at the increased activity of some glycolytic enzymes may be, at least in pa rt, the result of the reactive astrocytosis developing in the course of AD.