- USA: For Research Use Only. Not For Use In Diagnostic Procedures.
Cortisol is the most abundant circulating steroid and the majorglucocorticoid secreted by the adrenal cortex. Cortisol is physi-ologically effective in blood pressure maintenance and anti-inflammatory activity. It is also involved in calcium absorption,gluconeogenesis as well as the secretion of gastric acid andpepsin. The levels of cortisol are increased under stress situ-ations, physical exercise and external administration of ACTH.
Most circulating cortisol is bound to corticosteroid-bindingglobulin (transcortin) and albumin. The amount of unbound orfree cortisol (which is considered the active fraction in blood),represents approximately 1–2% of the total amount in blood.
The measurement of salivary cortisol is considered to representthe free fraction, due to the absence of appreciable amountsof cortisol-binding proteins in saliva. The level of salivarycortisol shows a diurnal rhythm with the highest levels in themorning and the lowest levels at night. Studies consistentlyreport high correlations between serum and salivary cortisol,indicating that salivary cortisol levels reliably estimate serumcortisol levels.
The measurement of salivary cortisol levels can be used as anindicator of adrenal function and the differential diagnosis ofAddison’s and Cushing’s diseases