Figure 2.

Dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis in obesity. Excessive adipose tissue is responsible for increased concentrations of resistin and leptin and decreased concentrations of the anti-inflammatory adiponectin. This imbalance stimulates the HPA axis to produce cortisol, with elevated cortisol levels being linked to depression. Ghrelin secreted by the gastric parietal cells is also a hormone that stimulates the HPA axis, but its levels decrease in obesity, which may also contribute to HPA axis dysregulation: ↑ (increase), ↓ (decrease), + (stimulation), and – (inhibition).