Abstract
We often observe hypoglycemic symptoms to occur at a wide glycemic range. Some patients feel hypoglycemic symptoms at 90 mg/dl, while other patients don't feel them even as low as 40 mg/dl. To elucidate this diversity, we determined glycemic thresholds for counterregulatory hormone secretion and hypoglycemic symptoms by using an artificial pancreas. Twenty-six variously controlled diabetic patients, 1insulinoma patient, and9healthy controls were analyzed. Diabetics with recent episods of hypoglycemia had significantly lower thresholds for epinephrine than subjects without hypoglycemia. Diabetics had several glycemic thresholds for epinephrine at a wide glycemic range (30-110 mg/dl). The high-glycemic threshold group (more than mean±2 SD of healthy controls) had significantly higher HbA1c, 13.0±3.0%, than did the low-threshold group (less than mean-2SD). 7.8%.
In general, glycemic thresholds for epinephrine secretion parallel HbA1c, but hypoglycemic episods change this tendency. A lowered threshold for epinephrine in the insulinoma patient elevated toward the normal range after pancreatectomy. To the contrary, the glycemic threshold of a very poorly/controlled IDDM woman were elevated. Intensive insulin therapy for 1 month lowered it toward the normal range. In conclusion, continuous hyperglycemia may elevate the glycemic threshold for epinephrine secretion and autonomic symptoms, but episods of hypoglycemia may lower them. Avoiding hyperglycemia or hypoglycemia normalized abnormal glycemic thresholds.
