Lack of meal-related cortisol peak in patients with type 1 diabetes

Objectives: In healthy humans, serum cortisol concentrations have been shown to rise following a mid-day meal. So far, the meal-related cortisol peak has not been studied in patients with type 1 diabetes although type 1 diabetes is known to be accompanied by altered regulation of the hypothalamo-pituitary-adrenal (HPA) system as well as by altered metabolic and hormonal pattern during eating.

Methods: To determine whether hormonal and metabolic changes in type 1 diabetes lead to a disrupted HPA system response to eating, we examined 10 diabetic patients and 20 healthy controls. Concentrations of ACTH, cortisol, insulin and glucose were measured before and and after a mid-day standard meal.

Results: After the meal intake concentrations of glucose (P<0.001) insulin (P<0.001) and cortisol (P=0.012) but not of ACTH increased swiftly in the healthy subjects. Conversely, in the patients with type 1 diabetes cortisol concentrations did not increase after the meal and concentrations of glucose (P=0.029) and insulin (P=0.036) increased only slowly and prolonged if compared to the kinetics in healthy subjects. Insulin and cortisol peak concentrations were markedly higher in healthy subjects than in diabetic patients despite of preprandial insulin substitution.

Conclusion: The lack of a meal-related cortisol peak supports the notion of a hyporeactive HPA system in patients with type 1 diabetes and points to an association with diminished insulin rise after exogenous administration.