CORTISOL
Cortisol is a steroid hormone released from the adrenal gland in response to ACTH, a hormone from the anterior pituitary gland in the brain. Cortisol levels rise and fall during the day. Highest levels occur at about 6 to 8 a.m. and lowest levels at about midnight.
Cortisol affects many different body systems. It plays a role in lipid, carbohydrate, and protein metabolism. Cortisol also plays a role in the bone, circulatory, nervous, and immune systems. Cortisol is critical for normal stress responses.
Different diseases, such as Cushing's disease and Addison's disease, can lead to either over- or under-production of cortisol. Urinary free cortisol measurements can help to diagnose these conditions.
Urinary free cortisol is a measurement of the cortisol in the urine that is not attached to other substances. Free cortisol represents the active form of the hormone. The urine measurement directly reflects the blood level of cortisol. (Source: National Library of Medicine 2008)
