Kistik fibrozisli çocuklarda glukagonun glukoz regülasyonundaki rolü ve etkisi

Post-oral glucose tolerance test-related hypoglycemia is common and important issue in Cystic Fibrosis (CF). The underlying mechanisms of hypoglycemia are still controversial. The current mice studies show that CFTR gene is identified in alpha cells and regulates glucagon secretion. The aim of the study is to determine of the role and effect of glucagon in CF patients with hypoglycemia. A 3-hour OGTT was performed in 45 non-diabetic children with CF and 9 age-matched healthy controls. The subjects were classified based on OGTT as isolated hypoglycemia, hypoglycemia with abnormal glucose intolerance (AGT), AGT, CF related diabetes (CFRD) and normal glucose tolerance (NGT). After CFRD subjects were excluded, the demographic characteristics and plasma glucose, insulin and glucagon levels obtained at 0,60,120,150 and 180.min during OGTT were assessed. Isolated hypoglycemia group did not differ from NGT and controls in terms of age, sex, BMI and genetics. The frequency of isolated hypoglycemia, hypoglycemia + AGT, AGT and NGT were 31%(n=14), 18%(n=8), 11%(n=5) and 35.5%(n=16), respectively. Level 2 hypoglycemia (<54 mg/dL) was observed in 15% of the subjects. Basal glucagon level in NGT was significantly lower than the controls (p<0.05) and glucose-stimulated glucagon response were not observed in NGT. The glucagon levels at 60, 120 and 150.min in isolated hypoglycemia were significantly higher than controls (p<0.01, p<0.01, p<0.05, respectively). However, the statistically significant difference did not observe at 180.min (p=0.17) despite of higher insulin levels. These findings can be interpreted as the glucagon secretion is still sensitive to glycemic changing in isolated hypoglycemia group but not properly, whereas it was blunted in NGT. It might be suggested that NGT is more pathologic state than isolated hypoglycemia in terms of glucagon secretion.