Free Cortisol (Unconjugated Cortisol) is filtered by the kidneys and excreted in the urine. Elevated urine levels reflect elevated serum cortisol levels.
Cortisol is a potent glucocorticoid released from the adrenal cortex. This hormone affects the metabolism of carbohydrates, proteins, and fats. It has an especially profound effect on glucose serum levels. Cortisol tends to increase glucose by stimulating gluconeogenesis from glucose stores. It also inhibits the effect of insulin and thereby inhibits glucose transport into the cells.
The urine specimen is collected over a 24 hours period and kept on ice or refrigerated to avoid the possibility of false results.
Causes of False Urine Cortisol Indications
- Pregnancy causes increased Urine Cortisol Levels.
- Physical and emotional stress can increase Urine Cortisol Levels.
- Stress is stimulatory to the pituitary-cortical mechanism, which thereby stimulates cortisol production.
- Drugs that may cause increased Urine Cortisol Levels include Danazol, Hydrocortisone, Oral contraceptives, and Spironolactone (Aldactone).
- Drugs that may decreased Urine Cortisol Levels include dexamethasone, ethacrynic acid, ketoconazole, and thiazides.
Causes of High Urine Cortisol Levels
- When ACTH is overproduced as a result of neoplastic overproduction of ACTH in the pituitary gland or elsewhere in the body by an ACTH-producing cancer. Stress is a potent stimulus to ACTH production. Cortisol levels rise as a result. In additoin to
Stess, overproduction of ACTH can is associated with Cushing Disease and Ectopic ACTH-producing Tumors.
- Adrenal Adenoma or Adrenal Carcinoma: Neoplasm produces cortisol without regard to the normal feedback mechanism.
- Hyperthyroidism: Metabolic rate is increased and cortisol levels rise accordingly to maintain elevated glucose needs.
- Obesity: All sterols are increased in the obese, perhaps because fatty tissue may act as a depository or location of synthesis.
Causes of Low Urine Cortisol Levels
- Adrenal Hyperplasia: Congenital absence of important enzymes in the synthesis of cortisol prevents adequate serum levels.
- Addison Disease: As a result of hypofunctioning of the adrenal gland, cortisol levels drop.
- Hypopituitarism: ACTH is not produced by the pituitary gland destroyed by disease, neoplasm, or ischemia. The adrenal gland is not stimulated to produce cortisol.
- Hypothyroidism: Normal cortisol levels are not required to maintain the reduced metabolic rate in patients with hypothyroidism.