The hypothalamus, pituitary gland and adrenal glands are all responsible for cortisol production. The pituitary gland and hypothalamus are both found in the brain. Before cortisol is produced, the hypothalamus has to secrete a hormone called corticotropin-releasing hormone. This hormone then stimulates the pituitary gland to produce ACTH or corticotropin--a hormone that makes the adrenal glands release cortisol. Several factors can cause high levels of cortisol in the body including pituitary dysfunction.
Function
Cortisol has many functions in the body. It regulates blood pressure and glucose levels in the body. It also helps the body cope with stress, injury and periods of illness. The immune system helps the body fight off infection. Cortisol reduces the inflammatory effect of the immune system. Another function of cortisol is that it helps the cardiovascular system work properly.
Causes
Cushing's syndrome is a hormonal imbalance that occurs when the body is exposed to too much cortisol. Several factors contribute to increased levels of cortisol in the body. The Merck Manuals Online Medical Library says that a problem with the adrenal glands or the pituitary gland may lead to high cortisol levels. Over-production of ACTH in the pituitary gland can stimulate the adrenal glands to produce too much cortisol. Pituitary tumors can lead to ACTH over production.
Tumors in other parts of the body like the lungs can also secrete ACTH and cause high cortisol levels. This disorder is called ectopic ACTH syndrome. Furthermore, excessive production of cortisol can occur as a result of tumors in the adrenal glands. Patients who need to take large doses of corticosteroids--medications that are like cortisol--for medical conditions such as asthma may develop high blood cortisol levels.
Effects/Symptoms
Too much cortisol in the body causes weight gain around the abdomen, face, neck and upper back. It also makes a person more susceptible to infections. In this condition, the skin becomes thin and easily develops bruises that heal with difficulty. According to the National Endocrine and Metabolic Diseases Information Service, other signs of elevated cortisol levels are high blood glucose levels, high blood pressure, fatigue that is severe and muscle weakness. Anxiety, irritability and depression could also occur in people with high cortisol levels.
Diagnosis
To determine if a person has high cortisol levels, physicians measure the amount of cortisol in the blood. If the measurement reveals high cortisol levels, a dexamethasone suppression test is done. In this test, a patient is given dexamethasone. Then the amount of cortisol in the patient's blood is measured again. Dexamethasone suppresses pituitary function, so if the problem is from the pituitary gland, cortisol levels will be lower. If the cortisol levels remain high, then the problem may be due to another reason. Corticotropin levels in the blood can also be measured if pituitary problems are suspected to be the cause of high cortisol levels.
The Merck Manuals Online Medical Library explains that the adrenal glands, pituitary gland and lungs can be visualized with computed tomography or magnetic resonance imaging scans. If elevated cortisol levels are being caused by tumors, these imaging technologies will help the physician locate the tumors.
Treatment
Treatment for excess cortisol in the body depends on what caused the condition in the first place. If tumors are the culprit, they can be surgically removed from the body. In some cases, the adrenal glands may have to be removed. Drugs that inhibit cortisol production such as metyrapone may be used to treat high cortisol levels. For patients taking drugs that cause increased cortisol levels, slowly reducing the dose or replacing the drug with one that doesn't cause this problem may remedy this condition.
