Background: Congenital hyperinsulinism (CHI) causes severe hypoglycaemia in children, due to dysregulated insulin secretion from pancreatic β-cells. Glucagon, secreted from the pancreatic α-cells, is critical for blood glucose homeostasis. Somatostatin is secreted by Δ-cells of the islets and by extraislet neuroendocrine cells. Exogenous somatostatin potently inhibits insulin and glucagon release from pancreatic islets. Under normal physiological conditions, low blood glucose levels reduce insulin release and promote glucagon and somatostatin secretion.
Objective and hypotheses: To determine the changes in the plasma levels of glucagon and somatostatin in children with CHI at normoglycaemia and during hypoglycaemia.
Method: All children admitted at our tertiary centre with a diagnosis of CHI were included in the study. Blood samples for glucose, insulin, glucagon, and somatostatin were collected at the time of normoglycaemia and then at the time of hypoglycaemia screen. The children did not receive glucagon or octreotide infusions at the time of hypoglycaemia screen.
Results: Nine children (five males and four females) were included in the on-going study. Six children had ABCC8/KCNJ11 mutations. Three children had focal lesions in the pancreas and underwent partial pancreatectomy. The median value (25th75th interquartile range) for insulin, glucagon, and somatostatin at normoglycaemia was 12.3 mU/l (7.329.8); 52.0 pg/ml (33.572.0); and 8.0 pg/ml (3.010.0) and during hypoglycaemia was 9.3 mU/l (6.814.9); 58.0 pg/ml (40.568.5); and 7.0 pg/ml (3.011.0) respectively. There is a positive correlation between the somatostatin and insulin level (r=0.68; P=0.003) and somatostatin and glucagon level (r=0.48; P=0.045). But no correlation either between glucagon and insulin level (r=0.246; P=0.342) or glucose level (r=−0.066; P=0.800).
Conclusion: There was no statistically significant difference (P value >0.05) between insulin, glucagon, and somatostatin levels during normoglycaemia and hypoglycaemia in children with CHI. Our preliminary data highlights that the children with CHI have inadequate response of glucagon and somatostatin secretion during hypoglycaemia.
20 - 22 Sep 2014
European Society for Paediatric Endocrinology