[The hypothalamic-hypophyseal-adrenal axis in obesity]

Area of Science:

• Endocrinology
• Metabolic Research
• Neuroendocrinology

Background:

• The hypothalamic-pituitary-adrenal (HPA) axis plays a crucial role in stress response and metabolic regulation.
• Obesity is associated with dysregulation of the HPA axis, but the precise mechanisms remain unclear.

Purpose of the Study:

• To investigate the HPA axis response to different stimuli in women with essential obesity.
• To compare the effects of corticotropin-releasing factor (CRF), insulin hypoglycemia, and oral glucose load on ACTH and cortisol levels in obese versus non-obese women.

Main Methods:

• Assessed the HPA axis in 26 women with essential obesity and controls.
• Utilized corticotropin-releasing factor (CRF) test, insulin hypoglycemia test, and oral glucose load.
• Measured basal, peak, and integrated ACTH and cortisol levels.

Main Results:

• Obese subjects had significantly lower peak ACTH responses to CRF compared to controls.
• The integrated ACTH and cortisol responses to CRF were not statistically different but trended lower in obese subjects.
• Glucose inhibited cortisol in controls but not in obese subjects.
• Insulin hypoglycemia elicited a significantly higher ACTH and cortisol response in obese women than CRF.

Conclusions:

• Obesity may involve an altered pituitary response to CRF, potentially mediated by other factors.
• Metabolic stimuli, such as insulin hypoglycemia, may involve additional factors influencing the HPA axis in obese individuals.
• The findings suggest a complex HPA axis dysregulation in obesity beyond a simple CRF deficiency.