Blood Glucose Changes Induced by Cold, Epinephrine, and Norepinephrine in Dogs of Various Ages.

Summary Under the age of 5 days newborn dogs did not have a hyperglycemic response to cold exposure for one hour, while pups older than this, as well as adults, showed a significant rise in blood glucose. Epinephrine alone or combined with cold exposure produced a hyperglycemic effect in dogs of all ages, but‘the response was considerably lower in dogs under 5 days. Norepinephrine had a small and variable effect on blood glucose. The combination of norepinephrine with cold gave a somewhat larger and more consistent hyperglycemia, except in the youngest dogs, which had a hypoglycemic response. Dogs under 8 days had greater depression of rectal temperature in the cold after epinephrine than after saline or norepinephrine administration. In none of the animals did the calorigenic effects of the amines increase cold resistance, as indicated by rectal temperature changes.