Adrenocortical tumors: prevalence of impaired glucose tolerance and of "Paradoxical Rise" of cortisol during an oral glucose tolerance test.

Glucose tolerance and the behaviour of cortisol during an oral glucose tolerance test (OGTT) was investigated in 126 patients with adrenal "incidentalomas" (age: > 45 years) and in 129 age-matched controls. Impaired glucose tolerance (IGT) was found to be more common (p < 0.02) among patients with adrenal incidentalomas. Subdividing these patients by their body weight it was found that 29% (controls: 25%) of those with normal body weight (BMI 20 - 25 kg/m2) had IGT/DM. In overweight (BMI 25 - 30 kg/m2) and obese patients (BMI 30 - 40 kg/m2) the share of IGT/DM was 32% (controls: 19%) and 66% (controls 42%), respectively. The prevalence of a "paradoxical" rise in serum cortisol concentrations during the OGTT was slightly higher (p < 0.05) among patients with adrenal incidentaloma than among controls. Patients as well as controls with this abnormal behaviour of cortisol were characterized by lower basal serum cortisol concentrations (p < 0.01) but no association was seen with either the presence of IGT or with post-dexamethasone concentrations of serum cortisol. Thus both in patients with and without adrenal incidentalomas abnormal glucose tolerance is an age- and weight-dependent phenomenon unrelated to the post-prandial behaviour of serum cortisol concentrations.