[Clinical evaluation of hyperglucagonemia in patients with myotonic dystrophy (author's transl)].

In order to clarify the possible participation of glucagon in glucose intolerance in myotonic dystrophy, six patients with myotonic dystrophy were examined. Three out of the six patients had an abnormal oral glucose tolerance curve. Two had frank diabetic glucose tolerance curves and the other had a high glucose value at 30 min after glucose loading, which fell beyond the normal range (Mean +/- 2 S.D.). Total insulin response to oral glucose, calculated as insulin area, was significantly exaggerated (p less than 0.01 vs control value). In addition to these results, hyperglucagonemia was observed throughout the test in two patients with myotonic dystrophy. In the arginine infusion test, insulin response was not so exaggerated but plasma glucagon was significantly higher (p less than 0.05 vs control value) at each 30, 45, 60 minutes after arginine infusion, and the mean glucagon area under the curves was significantly greater (p less than 0.05 vs control value). None of the myotonic patients showed growth hormone or cortisol excess during an arginine infusion and/or insulin tolerance test. Three patients with myotonic dystrophy who had abnormal glucose tolerance curves showed absolutely or relatively high glucagon levels and exaggerated response to arginine infusion. These findings suggested that hyperglucagonemia might contribute to the appearance of glucose intolerance in myotonic dystrophy.