The hypothalamic-pituitary-adrenal axis in abdominal obesity

Because of its rapidly increasing incidence and of severe complications len ding to high morbidity and mortality rates, obesity has become a major publ ic health concern . Abdominal obesity, which is characterized by the predom inance of fat around the viscera within the peritoneal cavity, demonstrates a higher prevalence of metabolic and cardiovascular complications. Patient s with abdominal obesity show clinical features that are compatible with hy percortisolism. However no typical hyperactivity of the hypothalamic-pituit ary-adrenal axis has been demonstrated in obese patients. This may be cause d by the lack of sensitivity of current investigations Hypersensitivity of the adrenal cortex to ACTH action may be involved In order to assess this h ypothesis we have developed an intravenous intravenous ACTH 1-24 acute chal lenge using a physiological dose of I mu g and evaluated the cortisol respo nse in normal-weight subjects and inobese women, which,were in their period of genital activity. After iv administration of this dose, the increase of ACTH 1-24plasma concentration was short-lived and similar to that of endog enous ACTH 1-39 during a regular morning pulse, suggesting that such a chal lenge may be appropriate to evaluate adrenal sensitivity. We Sound that the cortisol response is significantly higher in abdominal than in femoral obe sity or than in normal-weight subjects.