What are adrenal glands?
Your adrenal glands, also known as suprarenal glands, are small, triangle-shaped glands that are located on top of each of your two kidneys. They’re a part of your endocrine system and produce certain hormones that help regulate several important bodily functions, including:
- Metabolism (how your body transforms and manages energy from the food you eat).
- Immune system.
- Blood pressure.
- Response to stress.
- Development of sexual characteristics.
Your adrenal glands are composed of two parts: the cortex (outer region) and the medulla (inner part). Each part is responsible for producing different hormones.
What is the endocrine system?
Your endocrine system is a network of several glands that create and secrete (release) hormones.
A gland is an organ that makes one or more substances, such as hormones, digestive juices, sweat or tears. Endocrine glands release hormones directly into your bloodstream.
Hormones are chemicals that coordinate different functions in your body by carrying messages through your blood to your organs, skin, muscles and other tissues. These signals tell your body what to do and when to do it.
The following organs and glands make up your endocrine system:
- Pituitary gland.
- Parathyroid glands.
- Adrenal glands.
- Pineal gland.
What do your adrenal glands do?
Your adrenal glands are responsible for producing and releasing the following essential hormones:
- Cortisol: Cortisol is a glucocorticoid hormone that plays several important roles. It helps control your body’s use of fats, proteins and carbohydrates. It also suppresses inflammation, regulates your blood pressure, increases blood sugar and helps control your sleep-wake cycle. Your adrenal glands release cortisol during times of stress to help your body get an energy boost and better handle an emergency situation.
- Aldosterone: Aldosterone is a mineralocorticoid hormone that plays a central role in regulating blood pressure and the levels of sodium and potassium (electrolytes) in your blood. This means aldosterone helps regulate your blood pH (how acidic or basic it is) by controlling the levels of electrolytes in your blood.
- DHEA and androgenic steroids: These hormones are weak male hormones, meaning they don’t have much biologic impact. They are converted into female hormones (estrogens) in the ovaries and into male hormones (androgens) in the testes. Androgens are usually thought of as male hormones, but the female body naturally produces a small number of androgens too.
- Adrenaline (epinephrine) and noradrenaline (norepinephrine): These hormones are known as the “fight or flight” hormones and are called catecholamines. Adrenaline and noradrenaline are capable of increasing your heart rate and force of heart contractions, increasing blood flow to your muscles and brain and assisting in glucose metabolism. They also control the squeezing of your blood vessels (vasoconstriction), which helps maintain blood pressure. Your adrenal glands often release these hormones, like other adrenal hormones, when you’re in physically and emotionally stressful situations.
These hormones can be categorized into two broad groups:
- Catecholamines: Catecholamines are a group of similar substances that your body releases into your blood in response to physical or emotional stress. The primary catecholamines are dopamine, adrenaline and noradrenaline. The adrenal medulla, the inner part of your adrenal glands, produces and releases the catecholamines adrenaline and noradrenaline.
- Steroid hormones: Steroid hormones help control metabolism, inflammation, immune system functions, salt and water balance, development of sexual characteristics and the ability to withstand injury and illness. The adrenal cortex, the outer region of your adrenal glands, produce and release glucocorticoids, mineralocorticoids and adrenal androgens, which are all types of steroid hormones.
What other organs and glands interact with the adrenal glands?
Many other parts of your body interact with your adrenal glands, including:
- Pituitary gland.
- Sympathetic nervous system.
Your adrenal glands are controlled in part by your hypothalamus and pituitary gland. The hypothalamus, a small area of your brain involved in hormonal regulation, produces corticotropin-releasing hormone (CRH) and antidiuretic hormone (ADH, or vasopressin). ADH and CRH trigger your pituitary gland to release corticotropin (adrenocorticotropic hormone or ACTH), which stimulates your adrenal glands to produce corticosteroids, such as cortisol and aldosterone.
Your kidneys play a part in causing your adrenal glands to produce more or less aldosterone, and your sympathetic nervous system regulates the release of adrenaline and noradrenaline from your adrenal glands.
Can a person live without adrenal glands?
Your adrenal glands produce hormones that you can't live without, including sex hormones and cortisol. Although it’s rare, you can have both of your adrenal glands surgically removed (adrenalectomy) to treat certain adrenal conditions. People who have this surgery need to take certain medications for life to replace the adrenal gland hormones.
Where are the adrenal glands located?
You have two adrenal glands that are located on top of each of your kidneys. Your kidneys are located underneath your ribcage on each side of your spine.
What are the parts of the adrenal glands?
Both of your adrenal glands consist of two main parts:
- Medulla: The medulla is the inner part of your adrenal gland, and it releases the hormones adrenaline (epinephrine) and noradrenaline (norepinephrine). These hormones help control your blood pressure, heart rate, sweating and other activities that are also regulated by your sympathetic nervous system.
- Cortex: The cortex is the outer part of your adrenal gland, and it releases corticosteroid and mineralocorticoid hormones. The adrenal cortex also stimulates the production of small amounts of male sex steroid hormones (androgenic steroids).
How big are the adrenal glands?
Adrenal glands are normally about a half-inch high and three inches long. They’re shaped like rounded triangles.
Conditions and Disorders
What common conditions and disorders affect the adrenal glands?
There are several different adrenal gland disorders. They happen when your adrenal glands make too much or not enough of one or more hormones. Some adrenal conditions are temporary, whereas others are chronic (lifelong).
Causes of adrenal gland disorders include:
- Genetic mutations (changes).
- Autoimmune diseases.
- Tumors, such as pheochromocytomas.
- Damage to your adrenal glands through injury, infection or blood loss.
- An issue with your hypothalamus or pituitary gland, which both help regulate your adrenal glands.
- Certain steroid medications, such as prednisone and dexamethasone.
Adrenal gland conditions include:
- Addison’s disease (primary adrenal insufficiency): This is a rare autoimmune disease that causes your adrenal glands to produce lower-than-normal levels of cortisol and aldosterone.
- Cushing’s syndrome: This condition happens when your adrenal glands produce too much cortisol. It’s usually caused by a tumor or certain medications.
- Congenital adrenal hyperplasia: This is a condition you’re born with where your body lacks an enzyme that your adrenal glands need to make hormones.
- Excessive hair growth (hirsutism): This condition happens when women and people assigned female at birth (AFAB) develop excessive hair growth due to high levels of androgen, which your adrenal glands make.
- Primary aldosteronism (Conn’s syndrome): This condition happens when your adrenal glands produce too much aldosterone.
- Massive bilateral adrenal hemorrhage (Waterhouse-Friderichsen syndrome): This is an acute condition that leads to adrenal gland failure due to bleeding into the gland. It’s usually associated with a severe infection called sepsis.
What are the early warning signs and symptoms of adrenal gland problems?
The symptoms of adrenal gland issues vary depending on which hormones are affected. Many of the symptoms of adrenal disorders are similar to those of other illnesses.
Signs and symptoms that are relevant to the bodily processes your adrenal gland hormones affect include:
- Metabolism symptoms: Unexplained weight gain or weight loss, fatigue, frequent high blood sugar or low blood sugar, weakness.
- Immune system symptoms: Frequent sickness or infections.
- Blood pressure symptoms: High blood pressure (hypertension) or low blood pressure (hypotension).
- Sexual characteristics symptoms that affect females and prepubescent males: Growing facial hair and or balding, developing acne, having a deeper voice and becoming more muscular.
What tests check the health of my adrenal glands?
If you’re experiencing symptoms of possible adrenal gland issues, your healthcare provider can order certain blood and urine tests that measure the level of different adrenal hormones.
If the results reveal abnormal levels, your provider may order imaging tests such as CT (computed tomography) scans or MRIs (magnetic resonance imaging).
Your regular healthcare provider may refer you to an endocrinologist, a specialist in hormones and diseases of the endocrine system.
When should I see my doctor about my adrenal glands?
If you have concerning symptoms such as high or low blood pressure and unexplained weight loss or weight gain, reach out to your healthcare provider. While many conditions could cause these symptoms, it could be an issue with your adrenal glands.
A note from Cleveland Clinic
Your adrenal glands produce many important hormones that are necessary for everyday bodily functions. If you have any adrenal disorder-related symptoms or want to know if you have any risk factors for developing an adrenal condition, don’t be afraid to talk to your healthcare provider. They’re there to help you.
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