A preliminary account of these results was presented at the 10th Annual Meeting of the American Society for Neurochemistry, Charleston, South Carolina, March 11–16, 1979.
Cerebral Cortical Glucose Utilization in the Conscious Rat: Evidence for a Circadian Rhythm
Article first published online: 5 OCT 2006
Journal of Neurochemistry
Volume 34, Issue 6, pages 1700–1706, June 1980
How to Cite
Crane, P. D., Braun, L. D., Cornford, E. M., Nyerges, A. M. and Oldendorf, W. H. (1980), Cerebral Cortical Glucose Utilization in the Conscious Rat: Evidence for a Circadian Rhythm. Journal of Neurochemistry, 34: 1700–1706. doi: 10.1111/j.1471-4159.1980.tb11263.x
- Issue published online: 5 OCT 2006
- Article first published online: 5 OCT 2006
- Received July 27, 1979; accepted December 13, 1979.
- Brain glucose;
- Glucose utilization;
- Plasma glucose
Abstract: The presence of a circadian rhythm of glucose utilization was demonstrated in vivo in rat cerebral cortex. The activity pattern of the rats, living in a controlled lighting regimen with lights on from 7 a.m. to 7 p. m., appeared to coincide with the rate of glucose consumption in the brain. The rate of utilization was measured at 3-h intervals throughout the day and was found to fall from a maximum at 3 a.m. of 0.98 ± 0.13 μmol min−1 g−1 to a minimum of 0.70 ± 0.08 μmol min−1 g−1 at 3 p. m. Brain glucose also varied with time and its fluctuating level weakly correlated with its rate of utilization. Animals entrained on a 5-h (4: 30-9: 30 p. m.) feeding schedule had a similar circadian rhythm, with only a slight increase in amplitude. Reversal of the light cycle caused a disruption in the normal rhythm, but utilization still varied significantly with time of day. The results both indicate the potential error that can be encountered in experiments done at different times of the day and stress the need for awareness of time of day as a factor in measurements of alterations of metabolic rate in the brain.