Hyperglycemia in Response to Hypoglycemia in Normal and Hypophysectomized Dogs

Abstract

Somogyi 1 has observed on diabetic as well as on non-diabetic human beings that hypoglycemia is followed by a compensatory hyperglycemia, After hypoglycemia in the postabsorptive state the blood sugar rises and in many cases temporarily exceeds the fasting level. In other words, there is a hyperglycemia relative to the fasting blood sugar. This phenomenon has not been generally noted because most workers do not observe the course of the blood sugar level long enough following hypoglycemia.

We report here the occurrence of the same phenomenon in normal and in hypophysectomized dogs, observed during studies of their carbohydrate metabolism. Hypoglycemia was produced by 2 different procedures: (1) by oral or intravenous administration of glucose; (2) by intravenous injection of moderate doses of insulin.

In the first type of experiment, several hours after the administration of glucose the blood sugar fell below the fasting level, and this hypoglycemia was followed by hyperglycemia within 6 hours after the administration. It may be seen in Table I that the compensatory hyperglycemic response after hypoglycemia occurred in hypophysectomized animals about as in the normals.

In the second group of experiments, hypoglycemia that did not reach the convulsive level was the result of the injection of insulin in moderate doses. As shown in Table II, the compensatory hyperglycemic response again appeared, as after the hypoglycemia elicited by the administration of glucose, both in normal and in hypophysectomized dogs.

Instances of hyperglycemia in response to hypoglycemia are to be found in blood sugar curves after the injection of insulin, in experiments reported by Lucke, Heydeman and Hechler.