Effects of norepinephrine on blood glucose and free fatty acids in cold-adapted rats

¹ Department of Pharmacology, University of Toronto, Toronto, Canada

Norepinephrine (0.5 mg) was given intraperitoneally to albino rats adapted to room temperature (23 C) and to cold (2 C). The rats were killed at selected time intervals thereafter, and the blood levels of free fatty acids (FFA) and glucose were estimated. Both groups showed an initial steep rise in blood FFA and a slight rise in blood glucose. After 1 hr the FFA levels were at their maximum in the 2 C rats but had fallen to nearly base-line levels in 23 C rats. Blood glucose levels remained slightly elevated for the whole 1-hr period in the 2 C rats, but in the 23 C rats a secondary greater rise took place toward the end of the period. Different metabolic responses follow the administration of a single dose of norepinephrine to 2 C and 23 C rats.