Effects of ageing on local rates of cerebral glucose utilization in the rat.

The effects of ageing on local rates of glucose utilization in 47 brain structures in resting conscious rats have been examined. Three age groups have been studied: young adult (4 to 6 months), middle-aged (14 to 16 months), and aged (26 to 36 months). The results show that ageing per se is associated with decreases in rates of glucose utilization in specific brain regions. The decreases were not progressive with age, probably because of the influence of a survival effect. Age-related pathological changes are known to occur in some of the brain structures in which decreases in rates of glucose utilization were found. Selective decreases were also found in the caudate-putamen, the parietal cortex and in structures associated with vision and audition. In these latter structures the changes may reflect reductions in local functional activity, perhaps due to decreased sensory input from the primary sensory organs.