Cortisol is the major glucocorticoid produced and secreted by the adrenal cortex. It affects the metabolism of protein, fat and carbohydrates; the maintenance of muscle and myocardial integrity; and the suppression of inflammatory and allergic activities. Production of cortisol from the adrenal cortex is dependent upon corticotrophin (ACTH), which is secreted by the anterior pituitary. The corticotrophin-releasing factor (CRF) that regulates ACTH is secreated by the hypothalamus and is responsive to cortisol levels. Physical, psychological and surgical stress and diuranal variation will affect the rate of cortisol production.
Cortiscosteroid-binding globulin and albumin bind approximately 90% of the cortisol secreted by the adrenal cortex. Bound cortisol circulates in an available but temporarily inactive state. The physiological activity of cortisol depends upon levels of the small fraction of circulating unbound cortisol.
The measurement of cortisol levels aids in the diagnosis of normal and abnormal states of adrenal gland function. It is also helpful in the diagnosis of Cushing's disease (high cortisol) and Addison's diseases (low cortisol). The ACTH stimulation test is used to distinguish between primary and secondary adrenal insufficiency5. Suppression tests using dexamethasone and metyrapone are used to check the integrity of feedback system and are useful in the diagnosis of Cushing's disease. http://www.creative-diagnostics.com/Cortisol-Human-ELISA-Kit-184835-465.htm