Regional development of glutamate dehydrogenase in the rat brain

The development of glutamate dehydrogenase enzyme activity in rat brain regions has been followed from the late foetal stage to the adult and through to the aged (greater than 2 years) adult. In the adult brain the enzyme activity was greatest in the medulla oblongata and pons greater than midbrain = hypothalamus greater than cerebellum = striatum = cortex. In the aged adult brain, glutamate dehydrogenase activity was significantly lower in the medulla oblongata and pons when compared to the 90-day-old adult value, but not in other regions. The enzyme-specific activity of nonsynaptic (free) mitochondria purified from the medulla oblongata and pons of 90-day-old animals was about twice that of mitochondria purified from the striatum and the cortex. The specific activity of the enzyme in synaptic mitochondria purified from the above three brain regions, however, remained almost constant.