Cortisol is a hormone released in times of stress that helps regulate the body's stress response. A number of tissues throughout the body respond to cortisol in the blood to help regulate blood sugar, sugar and fat metabolism, blood pressure and inflammation. Cortisol levels in the blood are tightly regulated, and too much or too little cortisol can lead to harmful symptoms and disease. A number of underlying disorders can lead to low cortisol levels.
Hypopituitarism
The pituitary gland, located at the base of the brain, is responsible for the secretion of a number of hormones, including those that regulate cortisol levels. Specifically, some cells of the pituitary release a hormone called ATCH. Secretion of ATCH signals for the secretion of cortisol from the adrenal glands, glands found on top of the kidneys. Hypopituitarism is a disease in which there is insufficient hormone production in the pituitary. If less ATCH gets produced, less cortisol is secreted by the adrenal glands, and overall cortisol levels drop.
Hypopituitarism can be caused by cellular dysfunction within the gland or from the development of a pituitary tumor. Merck reports that hormone replacement therapy can be used to supplement hormone levels to mimic proper pituitary function, and surgical removal of a pituitary tumor can treat the cause of low cortisol levels.
Addison's Disease
Another potential cause of low cortisol levels is Addison's disease, also called primary adrenal dysfunction. It occurs when the adrenal glands are damaged. The damaged glands cannot properly secrete cortisol in response to ATCH, so the overall levels of cortisol in the blood drop. The National Endocrine and Metabolic Diseases Information Service indicates that Addison's disease affects one in 25,000 to 100,000 people and equally affects patients of both genders and all ages.
Addison's is generally caused by an immune disorder that causes the immune system to attack the outer layers of the adrenal glands. It can also be caused by tuberculosis, infections or cancer metastasis to the adrenal glands. Low cortisol levels as a result of Addison's disease can be treated with hormone supplementation.
Secondary Adrenal Insufficiency
Another potential cause of low cortisol levels is secondary adrenal insufficiency. Secondary adrenal insufficiency occurs when the adrenal glands shrink and become dysfunctional due to lack of ATCH stimulation. It may occur as a result of hypopituitarism or as a result of damage to other structures within the brain. Secondary adrenal insufficiency may also develop if a patient has recently stopped using corticosteroids, or cortisol-mimicking drugs. Merck explains that long-term use of corticosteroids can lead to decreased ATCH secretion in the pituitary gland, which leads to insufficient ATCH levels once the drugs are stopped. The treatment for secondary adrenal insufficiency may include cortisol replacement therapy.
