Utilization of glucose by the hypothermic rat

Abstract

Hyperglycemia of several hours duration was shown to occur in fasted rats given a small glucose load at a body temperature of 18 C. To eliminate the possibility that continued formation of glucose from glycogen produced the hyperglycemia, carbohydrate balance studies were made. The glycogen in the livers of cooled rats was the same with and without a glucose load, indicating a failure in ability to store glycogen. After injection of C¹⁴-labeled glucose into hypothermic rats, the specific activity of glucose in the plasma remained constant for 2 1/2 hr. This is further evidence that endogenous glucose is not added to the extracellular phase during hypothermia. The rate of uptake of glucose by muscle was measured at 38 and 18 C, and these results compared with those obtained in the whole animal. Removal of glucose from the blood is far slower than expected from physical chemical effects of temperature. Failure to convert glucose to glycogen may be the cause of the hyperglycemia in hypothermia.