Evolution of Abnormal Plasma Glucagon Responses to Mixed-Meal Feedings in Youth With Type 1 Diabetes During the First 2 Years After Diagnosis

OBJECTIVE: To examine the evolution of the dysregulated glucagon responses to mixed-meal tolerance tests (MMTTs) in youth with recent-onset type 1 diabetes (T1D). RESEARCH DESIGN AND METHODS: MMTTs were performed in 25 youth (9-18 years of age) with 1.5-12 months disease duration (year 1); 22 subjects were restudied 1 year later (year 2). Twenty nondiabetic (ND) control children were also studied. RESULTS: In T1D children, MMTT-stimulated increases in glucagon were significantly greater than that in ND children (median increments: year 1, 21 pg/mL [16-30]; year 2, 25 pg/mL [16-30]; ND, 9 pg/mL [5-16]; P = 0.001 and P < 0.001, respectively). CONCLUSIONS: In comparison with ND control children, exaggerated plasma glucagon responses to mixed-meal feedings are observed in youth with T1D within the first 2 years of diagnosis. Further studies to determine whether suppression of these abnormal responses may help to improve glycemic control are warranted.