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Insulin and glucagon response to arginine infusion in cystic fibrosis
Insights
Children with cystic fibrosis (CF) show reduced insulin secretion. Glucagon responses vary, with some severe cases exhibiting high levels potentially from stress or extrapancreatic sources.
Area of Science:
- Endocrinology
- Pediatrics
- Metabolic Disorders
Background:
- Cystic Fibrosis (CF) is a genetic disorder affecting multiple organs, including the pancreas.
- Pancreatic dysfunction in CF can impact hormone secretion, affecting glucose metabolism.
- Understanding hormonal responses in CF is crucial for managing associated complications.
Purpose of the Study:
- To investigate the glucagon and insulin responses to intravenous arginine in children with cystic fibrosis.
- To compare these hormonal responses with those in healthy control children.
- To correlate hormonal secretion patterns with disease severity in cystic fibrosis.
Main Methods:
- Studied 17 children with cystic fibrosis and 9 control children.
- Administered intravenous arginine to stimulate hormone release.
- Measured glucagon and insulin levels in response to arginine challenge.
Main Results:
- Overall diminished insulin secretion was observed in children with cystic fibrosis.
- Glucagon responses were variable: seven normal, four excessively high, and six low.
- Four children with severe CF and high glucagon output also had fasting hypoglycemia and low insulin response.
Conclusions:
- Confirmed diminished insulin secretion in cystic fibrosis.
- Diminished glucagon secretion was noted only when some insulin secretion was preserved.
- High glucagon levels in insulin-deficient CF patients may be extrapancreatic or stress-related, possibly linked to severe pulmonary involvement.
Abstract:
The glucagon and insulin responses to intravenous arginine were studied in 17 children with cystic fibrosis and in 9 control children. It was found that the overall secretion of insulin was diminished; however, four of the CF children did have a normal output. The glucagon responses did not parallel those of insulin. The glucagon output varied in the CF children--seven had normal, four excessively high and six low output. Three of the four children with extremely high output had more severe disease and were below the third centile on the weight chart. These four had a fasting hypoglycaemia and also a very low glucose and insulin response. We have confirmed diminished insulin secretion in cystic fibrosis, but diminished glucagon secretion was only noted when some insulin secretion was preserved. The high levels of glucagon seen in the most insulin deficient subjects may be derived from extrapancreatic sources, or may be associated with 'stress' reaction in these patients who also had most severe pulmonary involvement. The data would be consistent with diminished glucagon and insulin secretion from the pancreas but as the disease progresses an excessive secretion of extra pancreatic glucagon results.