Glucagon-like peptide-2 and glucagon in patients with acromegaly and Cushing’s disease: secretion features and influence on glucose metabolism

Abstract

Aim. To analyze secretion of GLP-2 and glucagon in patients with Cushing’s disease (CD) and acromegaly in response to glucose load.
 Material and methods. The study included 42 patients with Cushing’s disease and acromegaly; the mean patient age was 37.5 years. All patients were newly diagnosed with Cushing’s disease and acromegaly: none of them had a history of previous drug therapy, radiotherapy, or pituitary surgery. All patients underwent the oral glucose tolerance test with measurements of glucose, glucagon, and GLP-2 levels at 0, 30, and 120 min, respectively.
 Results. A significantly higher glucagon level was observed in CD patients at all cut-off points (р=0.001); in acromegaly patients, the glucagon level did not significantly differ from that in controls (р=0.12). The GLP-2 concentration in CD patients was also significantly higher compared to that in controls (р<0.001). There were no significant differences between acromegaly patients and controls. We also found a strong correlation between GLP-2 and glucagon levels at 0 and 30 min in CD patients. In acromegaly patients, a correlation between GLP-2 and glucagon levels was observed only at 0 min. Different GLP-2 and glucagon secretion patterns in patients with CD and acromegaly suggest a direct influence of glucocorticoids on glucagon secretion and no influence in the case of IGF-1.
 Conclusion. The found correlation between GLP-2 and glucagon levels might help specify the role of GLP-2 in carbohydrate metabolism regulation. Interactions of cortisol, IGF-1, and GLP-2 look promising for a better understanding of secondary hyperglycemia pathogenesis.