Cause of hypoglycemia in dogs exposed to heat

Abstract

When unanesthetized dogs are exposed to heat (120°F) for 4 hr. with no water available for drinking, hypoglycemia results. One would expect that the dehydration, which also occurs, should physically cause an increase in blood glucose concentration as is usually found in man. The tendency is present in dogs but the utilization of glucose is sufficiently rapid to offset the hemoconcentration and cause a fall in glucose levels even when exogenous glucose is given at the rate of 1% body wt/hr. of 11% glucose by stomach tube. This increased utilization has been demonstrated to be mainly due to involvement of the respiratory muscles which are used in the panting mechanism for no fall in blood glucose occurs under similar conditions when the animal is curarized. The evidence indicates that the hypoglycemic mechanism present in dogs is not a species phenomenon but is probably also present in man under appropriate conditions. In both man and the dog whether hypoglycemia occurs will depend upon the degree of involvement of the respiratory apparatus.