Correlation of age and body weight with local cerebral glucose utilization in 8-14 week-old rats

The regional cerebral metabolic rate for glucose (rCMRgl) in 8-14 week-old, male, albino, Wistar rats, weighing 200-385 g was autoradiographically measured using the [14C]2-deoxyglucose (2-DG) technique. Three age-weight groups of rats were tested: (I) 8-9 weeks old (200-250 g, average 227 +/- 14); (II) 10-11 weeks old (255-300 g, average 280 +/- 15 g); (III) 12-14 weeks old (305-385 g; average 331 +/- 25 g). A gradual reduction in rCMRgl was observed in the older and heavier groups. The reductions were statistically significant in 18/28 investigated structures in group III as compared to group I. Since such significant variation in the investigated age-weight range may affect rCMRgl values obtained in different experiments, it is suggested to use narrow and uniform age-weight groups for experimentation concerning brain metabolic functions.