The Adrenal Glands and Adrenal Diseases

Overview

The adrenal glands are two small glands (each weighs about 4 to 6 grams) located in the back of the abdomen immediately above the kidneys. The adrenal glands make a variety of hormones that are essential to maintaining the normal function of the body. The glands consist of an outer part called the cortex and an inner part called the medulla. If the adrenal gland were a peanut butter sandwich, the cortex would be the bread and the medulla the peanut butter.

The adrenal cortex, or outer portion of the adrenal gland has three layers, each making a different hormone:

  • Layer: Zona glomerulosa
    Location: Outermost
    Hormone: Aldosterone
    Function: Controls blood pressure
  • Layer: Zona fasciculata
    Location: Middle
    Hormone: Cortisol
    Function: Controls immune system, inflammation, stress response
  • Layer: Zona reticularis
    Location: Innermost
    Hormone: Sex hormones (testosterone, estrogen)
    Function: Control reproductive organs and development of male/female characteristics

The adrenal medulla, or inner portion of the adrenal gland, produces a group of hormones known as catecholamines. These hormones help with the 'fight or flight' response (i.e. helps you respond to stressful situations) and are better known as adrenaline.

Normal adrenal glands on CAT scanAdrenal disease usually occurs when there is a tumor (either cancer or benign) and/or a hyperactive adrenal gland that makes too much of any of these hormones. The main diseases of a hyperactive adrenal gland include: primary hyperaldosteronism (too much aldosterone), Cushing's syndrome (too much cortisol), and pheochromocytoma/paraganglioma (too much adrenaline). The early detection and treatment of adrenal disease can significantly improve outcomes and profoundly improve a patient's quality of life. While some adrenal diseases can be inherited (i.e. linked to specific genes or syndromes), most of the time they are sporadic or random. The following sections will provide information about adrenal conditions and their symptoms, diagnosis, treatment, and, where applicable, what is known about genetic causes.