Meal-stimulated glucagon release is associated with postprandial blood glucose level and does not interfere with glycemic control in children and adolescents with new-onset type 1 diabetes.

CONTEXT

The role of glucagon in hyperglycemia in type 1 diabetes is unresolved, and in vitro studies suggest that increasing blood glucose might stimulate glucagon secretion.

OBJECTIVE

Our objective was to investigate the relationship between postprandial glucose and glucagon level during the first 12 months after diagnosis of childhood type 1 diabetes.

DESIGN

We conducted a prospective, noninterventional, 12-month follow-up study conducted in 22 centers in 18 countries.

PATIENTS

Patients included 257 children and adolescents less than 16 yr old with newly diagnosed type 1 diabetes; 204 completed the 12-month follow-up.

SETTING

The study was conducted at pediatric outpatient clinics.

MAIN OUTCOME MEASURES

We assessed residual beta-cell function (C-peptide), glycosylated hemoglobin (HbA(1c)), blood glucose, glucagon, and glucagon-like peptide-1 (GLP-1) release in response to a 90-min meal stimulation (Boost) at 1, 6, and 12 months after diagnosis.

RESULTS

Compound symmetric repeated-measurements models including all three visits showed that postprandial glucagon increased by 17% during follow-up (P = 0.001). Glucagon levels were highly associated with postprandial blood glucose levels because a 10 mmol/liter increase in blood glucose corresponded to a 20% increase in glucagon release (P = 0.0003). Glucagon levels were also associated with GLP-1 release because a 10% increase in GLP-1 corresponded to a 2% increase in glucagon release (P = 0.0003). Glucagon levels were not associated (coefficient -0.21, P = 0.07) with HbA(1c), adjusted for insulin dose. Immunohistochemical staining confirmed the presence of Kir6.2/SUR1 in human alpha-cells.

CONCLUSION

Our study supports the recent in vitro data showing a stimulation of glucagon secretion by high glucose levels. Postprandial glucagon levels were not associated with HbA(1c), adjusted for insulin dose, during the first year after onset of childhood type 1 diabetes.