Endocrine Abstracts

Aim of the study: To analyze the dynamics and levels of incretins and neuropeptides secretion in patients with CD and acromegaly and therefore to specify the pathogenesis of carbohydrate metabolism disturbances.

Methods: Forty-two patients with Cushing disease and acromegaly were included into the study. All patients were newly diagnosed with Cushing disease and acromegaly. Oral glucose tolerance test (OGTT), during which glucose, glucagon, glucagon like peptide 1 and 2 (GLP1, GLP2), gastric inhibitory peptide (GIP) and ghrelin were measured at 0, 30 and 120 min respectively was performed.

Results: The presence of prediabetes was higher in CD patients (40% vs 23% in acromegaly). Insulin resistance (assesed by HOMA-IR) was extremely high in both groups (11–13). In CD patients glucagon levels were significantly higher at all cut off points compared to controls (p 0 min=0.001, 30 min=0.016, 120 min=0.025). GIP secretion was lower in CD patients. Acromegaly group was characterized by inverse rhythm of GIP secretion, with no peak level at 30′ P=0.324. Basal GLP-1 level was significantly higher in CD patients (P=0.047). Both groups were characterized by unusual GLP-1 secretion with no peak levels at 30 min. No significant differences were found while analysing GIP and GLP-1 secretion in subgroups, divided regarding the stage of carbohydrate metabolism disorders. GLP-2 levels were significantly higher in CD patients (0 min P<0.001, 30 min P=0.007, 120 min P < 0.001). Ghrelin levels were significantly higher in CD (0 min P=0.013 30 min P=0.002 120 min P=0.003) and acromegaly patients (0 min P=0.048 30 min P=0.023 120 min P=0.015) at all cut off points.

Conclusion: GIP and GLP-1 secretion in CD and acromegaly patients are characterized by an atypical rhythm with no peak levels which might mean that incretins are not playing the crucial role in carbohydrate disturbances that is seen in these patients. GLP-2 and ghrelin seem to influence and potentially regulate glucose homeostasis in CD and acromegaly patients.