Effect of prolonged insulin treatment on blunted plasma catecholamine and glucagon increase during insulin hypoglycemia in streptozotocin diabetic rats.

The role of prolonged insulin treatment of diabetic rats on the lack of glucagon and catecholamine increases in response to insulin-hypoglycemia was investigated. Streptozotocin diabetic rats were maintained in a normoglycemic state for a long period by intraperitoneal constant infusion of insulin with the Alzet osmotic minipumps. Hyperglucagonemia observed in diabetic rats was normalized with insulin treatment. However, the blunted response of glucagon during insulin-hypoglycemia was not altered with insulin treatment. On the other hand, in diabetic rats the diminished catecholamine response to insulin-induced hypoglycemia was rendered normal after insulin treatment. The data indicate that the lack of glucagon and catecholamine responses in diabetic rats in response to insulin-hypoglycemia can vary independently. The persistent decreased glucagon response in normoglycemic diabetics could be the cause of their impaired recovery from hypoglycemia.