Aging and cortisol resistance to suppression by dexamethasone: a positive correlation

Area of Science:

• Endocrinology
• Gerontology
• Neuroscience

Background:

• Dexamethasone suppression test (DST) is used to assess hypothalamic-pituitary-adrenal (HPA) axis function.
• Cortisol resistance to dexamethasone suppression is observed in depression and dementia.
• The role of aging in dexamethasone suppression resistance is not fully understood.

Purpose of the Study:

• To investigate the relationship between age and cortisol suppression response to dexamethasone in healthy adults.

Main Methods:

• 30 healthy subjects aged 17-78 years were studied.
• Dexamethasone (0.5 mg) was administered at 11 p.m.
• Serum cortisol concentrations were measured 9 hours after dexamethasone administration using radioimmunoassay.

Main Results:

• A significant positive correlation was observed between participant age and serum cortisol levels 9 hours post-dexamethasone.
• Older subjects exhibited higher cortisol concentrations, indicating reduced suppression.

Conclusions:

• Aging itself may contribute to increased cortisol resistance to dexamethasone suppression.
• This age-related phenomenon could be a factor in the HPA axis dysregulation seen in depression and dementia.