AIM: To investigate the dose-response relationship of subcutaneous glucagon administration on plasma glucose and on counterregulatory hormone responses during subcutaneous insulin induced mild hypoglycaemia in patients with type 1 diabetes treated with insulin pumps.

MATERIALS AND METHODS: Eight insulin pump treated patients completed a blinded, randomized, placebo-controlled study. Hypoglycaemia was induced in the fasting state by a subcutaneous insulin bolus and when plasma glucose reached 3.4 mmol/l (95%CI 3.2-3.5), a subcutaneous bolus of either 100, 200, 300 µg glucagon or saline was administered. Plasma glucose, counterregulatory hormones, haemodynamic parameters and side effects were measured throughout each study day. Peak plasma glucose was the primary endpoint.

RESULTS: Plasma glucose increased significantly by 2.3(1.7-3.0), 4.2(3.5-4.8) and 5.0(4.3-5.6) mmol/l to 6.1(4.9-7.4), 7.9(6.4-9.3) and 8.7(7.8-9.5) vs 3.6(3.4-3.9) mmol/l, p < 0.001 after the three different glucagon doses as compared with saline, and the increase was neither correlated with weight nor insulin levels. Area under plasma glucose curve, peak plasma glucose, time to peak and duration of plasma glucose above baseline were significantly enhanced with increasing glucagon doses; however, not significantly different between 200 and 300 µg glucagon. Free fatty acids and heart rates were significantly lower initially after glucagon compared with saline injection. Other haemodynamic parameters, counterregulatory hormones and side effects did not differ between interventions.

CONCLUSIONS: A subcutaneous low-dose glucagon bolus effectively restores plasma glucose after insulin overdosing. Further research is needed to investigate whether low-dose glucagon may be an alternative treatment to oral carbohydrate intake for mild hypoglycaemia in patients with type 1 diabetes.