Effect of hyperthermia on glucose homeostasis in young dogs. An experimental study.

Hyperthermia was produced in healthy anaesthetized young dogs by keeping them in a theromostatically controlled chamber, and the effects on blood glucose concentration were studies. The blood glucose levels decreased significantly at body temperatures of 40.5 degrees C and 42.5 degrees C. The decrease was greater at the latter temperature. Intravenous glucose tolerance tests were performed to study the rates of glucose utilization during hyperthermia. The calculated fractional rates of disappearance of glucose (Kt values) were found to be significantly higher in dogs having a body temperature of 42.4 degrees C. The cause of hypoglycemia produced at high body temperature seems to be due to an elevated insulin secretion which increases the over all utilization of glucose by the peripheral tissues. The study of time course of hyperglycemic response following intravenous glucose tolerance tests performed at high body temperature further support the possibility of an increase in insulin secretion in dogs subjected to hyperthermia.