Studies were designed to determine the effect, in diabetic patients, of insulin induced hypoglycemia upon alimentary hyperglycemia. The following results were obtained.
1. In a four-hour study, as a control day, each of four patients was given his usual insulin one hour before the oral administration of 100 gm. of glucose. On another occasion, under identical conditions, hypoglycemia was produced during the hour preceding glucose administration, by intravenous administration of Crystalline Insulin. There was no greater impairment of glucose tolerance during the subsequent three hours than noted in the control study.
2. In ten patients, maintained on constant diets for three consecutive days, blood sugars were determined at frequent intervals from 7 a.m. to 10 p.m. each day. Each patient, if insulin dependent, received his usual dose before breakfast on all three days. On the second day the administration of additional subcutaneous Crystalline Insulin produced hypoglycemia during the forenoon. No carbohydrate supplementation was given and generally the hypoglycemia was corrected only by lunch given at the usual time. The postprandial blood sugar elevations for the balance of that day and throughout the third day were no greater than those of the first or control day.
3. In one patient six identical studies were performed. In each instance 25 gm. of glucose was given by mouth at 7 a.m. on each of three consecutive days. Blood sugars were measured at two-hour intervals from 8 a.m. to 12 noon. On day two hypoglycemia was produced by the administration of 15-25 U. Crystalline Insulin after the 8 a.m. blood specimen was drawn. Although mean blood sugars were statistically significantly higher on day three than on day one at 8 a.m. and 12 noon, the quantitative measurement of urine sugar showed no increase over that of the control day on either the day of hypoglycemia or the following day.
These data do not support the concept, in patients with diabetes mellitus, that hypoglycemia is followed by further impairment of glucose tolerance.