A Study of Glucose Tolerance and Insulin Response in Partially Depancreatized Dogs

The effects of a standard glucose tolerance test (GTT) and of pretreatment with aminophylline (AM) were examined in dogs with a reduced reserve of islet function prepared by partial removal of the pancreas and in normal intact dogs. Serum glucose, free fatty acid and insulin levels were measured. No significant differences were found before and after partial pancreatectomy when less than 50 per cent of the pancreas was removed or after sham operation. When AM was infused prior to the GTT, serum insulin levels were elevated to almost twice those obtained during a standard GTT. Dogs with less than 50 per cent of the pancreas remaining showed deterioration in GTT two weeks after operation, although the fasting blood sugar was normal except in one animal. The deterioration in GTT response progressed with time. Maintaining the animal on a high protein diet improved the GTT response. In chow-fed dogs with less than 50 per cent of the pancreas but no glucosuria or fasting hyperglycemia, prior AM infusion significantly improved the GTT and increased insulin secretion. In one dog with fasting hyperglycemia, AM did not cause improvement.