There is one adrenal gland on top of each kidney. The gland is made of two parts. The adrenal medulla is the inner part of the gland. The adrenal cortex is the outer part. It makes up 90 percent of the gland and has three areas which are referred to as zones. Each zone is responsible for making specific hormones. Adrenal cortex disease results in too much or too little secretion of hormones.
Primary Aldosteronism
The zona glomerulosa, or the outer zone of the adrenal cortex, makes and secretes mineralocorticoids. These are steroid hormones. Aldosterone is the main mineralocorticoid the adrenal cortex secretes. In primary aldosteronism, the adrenal cortex secretes too much aldosterone. This is a common disease, as five to 10 percent of people with hypertension have high blood pressure because of primary aldosteronism, according to Paul Fitzgerald, M.D., Clinical Professor of Medicine at the University of California in "Current Medical Diagnosis & Treatment." Aldosterone tells the kidneys to keep sodium. But holding onto sodium means more water is reabsorbed. This causes the blood volume to increase, which increases the blood pressure. A benign tumor is the most common cause of this disorder.
Addison's Disease
In Addison's disease, the adrenal cortex has been destroyed. The adrenal gland secretes less mineralocorticoids and glucocorticoids. Next to the zona glomerulosa is the zona fasciculata. This zone makes the glucocorticoids, which are also steroid hormones. The main glucocorticoid is called cortisol. It increases the level of glucose in the bloodstream so people have energy to manage stress. People with Addison's disease have low levels of sodium and cortisol. Their symptoms may include low blood pressure, weakness, nausea, vomiting and increased skin pigmentation. Approximately 70 percent of this disease in America is due to an autoimmune disorder, writes Ashley Grossman, M.D., Professor of Neuroendocrinology at the London School of Medicine in "The Merck Manual for Healthcare Professionals." In an autoimmune disorder, the immune system attacks its own tissues and organs instead of only attacking foreign substances.
Cushing's Syndrome
People with Cushing's syndrome have high levels of cortisol in their bloodstream. There are several disorders which can cause this. People may have Cushing's disease, where they have a benign tumor in the anterior pituitary gland of the brain. This gland secretes the adrenocorticotropic hormone (ACTH), to tell the adrenal gland to secrete cortisol. But a pituitary tumor secretes ACTH without any regulation or control, as explained by Patricia Molina, M.D., Ph.D., head of the Department of Physiology at the Louisiana State University Health Sciences Center in "Endocrine Physiology." This leads to high cortisol levels. A carcinoid tumor and small cell lung cancer secrete ACTH without any regulation. Adrenal cancer and an enlarged adrenal gland secrete high levels of cortisol. The symptoms include abdominal obesity, a round face, a large amount of fat over the shoulders and purplish lines on the abdomen.
References
- "Current Medical Diagnosis & Treatment 2010"; Stephen McPhee, M.D., Maxine Papadakis, M.D.; 2010
- "Endocrine Physiology"; Patricia Molina, M.D., Ph.D.; 2010
- The Merck Manual for Healthcare Professionals: Addison's Disease
