Cross-talk between adipose tissue and the HPA axis in obesity and overt hypercortisolemic states

In addition to its roles in providing insulation and mechanical support, adipose tissue (AT) has been recognised as the major site for storage of surplus fuel. Since leptin was discovered, white AT (WAT) has been recognised as an endocrine organ and an important source of biologically active substances with local and/or systemic action called adipokines. The metabolic and endocrine activities of AT are under the control of several hormones: a particular role has been played by glucocorticoids (GC), which able to participate, along with other hormones, both in recruitment of progenitor cells and in differentiation and secretive activities. AT is also able to generate cortisol from cortisone through 11 beta-hydroxysteroid-dehydrogenase (11 beta-HSD). There are controversial reports in the literature, showing a hyperactivity of 11 beta-HSD in obesity. It has been postulated that obesity, particularly the visceral body fat distribution (V-BFD), may be considered a maladaptation to stress exposure, thus leading to hyperactivation of the hypothalamic-pituitary-adrenal (HPA) axis, and higher-than-normal cortisol levels. In this review, we will examine the cross-talk between the HPA axis and AT, their relationship under stressful events, depending on steroid hormones and different adipokine secretions.