Cushing's Syndrome: General Information

Cushing's Syndrome is a disease caused by an excess of cortisol production or by excessive use of cortisol or other similar steroid (glucocorticoid) hormones which is produced by the adrenal gland.
The Adrenal glands are located anterior to the kidneys. There are two main sections of the gland; the inner gland or medulla, and the outer gland, or the cortex. The medulla is part of the sympathetic nervous system, and secretes epinephrine and norepinephrine. The cortex functions as an endogenous gland and secretes three main hormones: glucocorticoids, minerocorticoids and sex hormones.
The adrenal cortex is controlled primarily by two endogenous glands in the brain: the hypothalamus, which produces corticotrophin-releasing hormone (CRH), and the pituitary which secretes adrenocorticotropic hormone (ACTH). CRH triggers ACTH, which stimulates the adrenal glands to produce steroids. An increase in the blood of the steroids triggers the pituitary to decrease secretion of ACTH. This self-regulating system usually works very effectively and efficiently to regulate the amount of steroids one’s body needs to function.
The adrenal cortex is a factory for steroid hormones. In total, at least two to three dozen different steroids are synthesized and secreted from this tissue, but one class is of particular importance, the glucocorticoids, of which cortisol is the most abundant.
Cortisol is a normal hormone produced in the outer portion, or cortex, of the adrenal glands, located above each kidney. The normal function of cortisol is to help the body respond to stress and change. It mobilizes nutrients, modifies the body's response to inflammation, stimulates the liver to raise the blood sugar, and it helps control the amount of water in the body.
The body controls the levels of corticosteroids according to need. The levels tend to be much higher in the early morning than later in the day. When the body is stressed, from illness or otherwise, the levels of corticosteroids increase dramatically. This is a protective adaptation to help our body cope with stress.
When too much cortisol is produced in the adrenal glands, or an excess is taken in treating other diseases, significant changes occur in all of the tissues and organs of the body. All of these effects together are called Cushing's Syndrome.