The pituitary response to ovine corticotropin-releasing hormone is enhanced in obese men and correlates with insulin resistance

Hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis in central o besity has been demonstrated in women. We studied the corticotropin (ACTH) and cortisol response to ovine corticotropin releasing hormone (oCRH) and i ts association to parameters of adiposity and insulin resistance in a group of 19 healthy obese (BMI > 25 kg/m(2)) and 9 non-obese men. Relative insul in resistance was assessed by the homeostatic model assessment (HOMA IR). B aseline ACTH was similar, while cortisol was lower in the obese group, The ACTH response to oCRH was significantly higher in the obese group. ACTH inc remental area under the curve (iAUC) correlated with age, HOMA IR, and sagi ttal diameter but not with leptin. In multiple regression analysis, only HO MA IR was an independent predictor of ACTH iAUC. In conclusion, obese men h ave hyperactivity of the HPA axis at the pituitary level, which appears to be linked to insulin resistance.