HUNTINGTON'S CHOREA: POST MORTEM ACTIVITY OF ENZYMES INVOLVED IN CEREBRAL GLUCOSE METABOLISM

— The loss of at least two different cell types in the basal ganglia of the choreic brain led us to examine the activity of enzymes involved in the metabolism of glucose. Cellular ATPase, HK, G6‐PDH, PFK., LDH, GDH were measured. Post mortem stability studies indicated that these enzymes were more unstable in human brain than mouse brain. The most stable enzyme was GDH. HK activity appeared to increase after freezing, suggesting release from another compartment. PFK and G6‐PDH activity decreased by 70% over the usual time and temperature period for autopsy. In the autopsied brain tissue we were still able to measure significant activities that allowed us to determine the distribution of these enzymes and the similar post mortem handling of control and choreic brain allowed us to compare these two groups. The activity of HK and G6‐PDH was higher in the frontal cortex than in the basal ganglia. Ouabain insensitive ATPase and PFK were higher in the basal ganglia than the frontal cortex. GDH activity, an enzyme that is very active in glial cells, was increased in the choreic globus pallidus, an area with a very high glial to neuronal cell ratio. Although there was a wide variation in PFK activity that appeared to be related to the pre‐mortem clinical state there was a significant decrease in PFK activity in the putamen of choreic post mortem brain when compared to controls. These findings do not indicate an absolute defect in any of the enzymes studied in choreic brain but further studies might prove worthwhile.