Hypoglycemic Response of Patients Using Protamine Zinc Insulin to Induced Hyperglycemia

Abstract

Some of the difficulties encountered in treating diabetes could be attributed to rapidly fluctuating blood sugar levels. The slow acceptance of protamine zinc insulin by the clinician was, in part, due to the occurrence of hypoglycemia episodes. They can be differentiated into two groups, the nocturnal, and the post-prandial. The former are obviously due to the unopposed prolonged action of Prozinsulin during the long fast from the evening meal to breakfast. An explanation for the latter type is given below.

Fifty-two diabetic patients using protamine zinc insulin exclusively for routine control were selected at random for the experiment. This consisted in the administration of 210 g to 420 g of orange juice, (25 to 50 g of glucose) 24 hours after the last insulin injection. Blood sugar estimations were made by the Somogyi (1936) modification of the Shaffer-Hartmann method in the fasting state, and at 0.5-hour intervals for 4 hours. The results shown in Table I with the controls, represent illustrative types of blood sugar variations seen in this series of experiments.

It is evident that the peak rise in the first 0.5 to 1.0 hr and the subsequent fall to fasting, or below fasting levels by the 3.0 hr resembles the normal glucose tolerance curve. In fact, many of the curves cannot be distinguished both in absolute change and contour from non-diabetic ones. Another point to be noted is that the rapidity of the rise has a direct bearing on the rate of fall, independent of the original blood sugar level. That is, the sharpest peak rise in blood sugar level is followed by the most precipitous drop. During the test period, patients with such curves manifested hypoglycemic symptoms. It will be noted that in the control curves where no food was given to the patient, the blood sugar level remained essentially unchanged for the 4-hr- period. It must be assumed that the amount of exogenous insulin present was the same both in the test period after orange juice, and in the control period.