Description
DHEA (Dehydroepiandrosterone) and its sulphate ester DHEA-S, as C-19 steroid hormones, belong to the group of androgens.
The zona reticularis of the adrenal glands produces approximately 80% of DHEA, with the remainder produced by the testes, ovaries, and brain. DHEA serves as a precursor in testosterone and estrogen synthesis. DHEA level in saliva samples reflects the circulating level of free bioactive steroid fraction in the body, rather than total circulating levels that are measured in blood, which are confounded by the presence of circulating binding proteins. DHEA levels show significant diurnal variation which is dependent on adrenocorticotrophic hormone (ACTH). DHEA has been shown to display a flat pattern of secretion after waking, followed by a progressive decline to 3 hours post-awakening with no significant change thereafter. The normal DHEA concentration changes significantly with age. The level of DHEA starts to increase at the adrenarche and reaches its maximum at the age of 20-30 years. After that the adrenal production of DHEA decline in both males and females, until concentrations of DHEA return to pre-adrenarche levels in persons over 80 years old. There is evidence of decreasing levels of DHEA and increased Cortisol/DHEA ratio to be involved in the cognitive and immune impairments in elderly people, as well as influencing the ability of older people to perform daily tasks. Higher Cortisol/DHEA ratios, rather than the hormone levels independently, have been associated with immune impairments and infection risk in older adults exposed to chronic physical and psychological stress. Acute Stress and Posttraumatic Stress Disorder are characterized by elevated level of DHEA in comparison to control groups, due to increased ACTH secretion initiated by stress and/or traumatic events. The key laboratory findings that help a clinician to evaluate the HPA axis status in an individual are total cortisol output, cortisol awaking response, cortisol diurnal rhythm, total DHEA(S) and Cortisol/ DHEA ratio. As such, the measurement of DHEA levels in saliva, in addition to other clinical observations and diagnostic test is useful in assessing the level of adrenal function as a determination of physiological status in aging adults. Measurements of DHEA levels are used by healthcare providers as an aid in the diagnosis and treatment of adrenal disorders in conjunction with measurements of other sex steroids like Testosterone, DHT and Androstenedione.
