Which endocrine gland is not essential for life?

All About the Adrenal Glands

Beyond fight or flight, these glands are essential to your body’s everyday functioning.

When you think of the adrenal glands (also known as suprarenal glands), stress might come to mind. And rightly so—the two adrenal glands are arguably best known for secreting the hormone adrenaline, which rapidly prepares your body to spring into action in a stressful situation.

But the adrenal glands contribute to your health even at times when your body isn’t under extreme stress. In fact, they release hormones that are essential for you to live. Here is a look at the anatomy and function of these glands that sit on top of your kidneys, as well as some of the things that can go wrong with them.

Anatomy of the Adrenal Glands

The adrenal glands are two triangular-shaped organs that measure about 1.5 inches in height and 3 inches in length. They are located on top of each kidney. Their name directly relates to their location (ad—near or at; renes—kidneys).

Each adrenal gland is made up of two distinct parts:

The adrenal cortex—the outer part of the gland—produces hormones that are vital to life, such as cortisol (which helps regulate metabolism and helps your body respond to stress) and aldosterone (which helps control blood pressure).

The adrenal medulla—the inner part of the gland—produces nonessential (that is, you don’t need them to live) hormones, such as adrenaline (which helps your body react to stress).

Hormones Made by the Adrenal Glands

The adrenal cortex and the adrenal medulla have very different functions. One of the main distinctions between them is that the hormones released by the adrenal cortex are necessary for life, while those secreted by the adrenal medulla are not.

Adrenal Cortex Hormones

The adrenal cortex produces two main groups of corticosteroid hormones: glucocorticoids and mineralocorticoids. The release of glucocorticoids is triggered by the hypothalamus and pituitary gland. Mineralocorticoids are mediated by signals triggered by the kidney.

When the hypothalamus produces corticotrophin-releasing hormone (CRH), it stimulates the pituitary gland to release adrenal corticotrophic hormone (ACTH). These hormones, in turn, alert the adrenal glands to produce corticosteroid hormones.

Glucocorticoids released by the adrenal cortex include:

  • Hydrocortisone: Commonly known as cortisol, it regulates how the body converts fats, proteins, and carbohydrates to energy. It also helps regulate blood pressure and cardiovascular function.
  • Corticosterone: This hormone works with hydrocortisone to regulate immune response and suppress inflammatory reactions.

The principle mineralocorticoid is aldosterone, which maintains the right balance of salt and water while helping control blood pressure.

There is a third class of hormone released by the adrenal cortex, known as sex steroids or sex hormones. The adrenal cortex releases small amounts of male and female sex hormones. However, their impact is usually overshadowed by the greater amounts of hormones (such as estrogen and testosterone) released by the ovaries or testes.

Adrenal Medulla Hormones

Unlike the adrenal cortex, the adrenal medulla does not perform any vital functions. That is, you don’t need it to live. But that hardly means the adrenal medulla is useless.

The hormones of the adrenal medulla are released after the sympathetic nervous system is stimulated, which occurs when you’re stressed. As such, the adrenal medulla helps you deal with physical and emotional stress.

You may be familiar with the fight-or-flight response—a process initiated by the sympathetic nervous system when your body encounters a threatening (stressful) situation. The hormones of the adrenal medulla contribute to this response.

Hormones secreted by the adrenal medulla are:

  • Epinephrine: Most people know epinephrine by its other name—adrenaline. This hormone rapidly responds to stress by increasing your heart rate and rushing blood to the muscles and brain. It also spikes your blood sugar level by helping convert glycogen to glucose in the liver. (Glycogen is the liver’s storage form of glucose.)
  • Norepinephrine: Also known as noradrenaline, this hormone works with epinephrine in responding to stress. However, it can cause vasoconstriction (the narrowing of blood vessels). This results in high blood pressure.

Adrenal Gland Disorders

There are multiple reasons why the adrenal glands might not work as they should. The problem could be with the adrenal gland itself, or the root cause may be due to a defect in another gland, such as the pituitary, that helps regulate the adrenal glands. In addition, some medications may cause problems in adrenal gland functioning.

Below are the most common disorders and diseases of the adrenal glands:

Addison’s Disease

This rare disorder may affect anyone at any age. It develops when the adrenal cortex fails to produce enough cortisol and aldosterone.

Adrenal Cancer

Adrenal cancer is a very rare cancer, but it is aggressive. Malignant adrenal tumors are rarely confined to the adrenal glands; they tend to spread to other organs and cause adverse changes within the body because of the excess hormones they produce.

Cushing’s Syndrome

Cushing’s syndrome is an uncommon condition that is essentially the opposite of Addison’s disease. It is caused by overproduction of the hormone cortisol. There are a variety of causes of this disorder, including a tumor in the adrenal gland or pituitary gland.

Congenital Adrenal Hyperplasia

This genetic disorder is characterized by low levels of cortisol. It’s common for people with congenital adrenal hyperplasia to have additional hormone problems such as low levels of aldosterone (which maintains a balance of water and salt).

Symptoms of Adrenal Gland Disorders

The symptoms of an adrenal gland disorder depend on which condition you have, since different adrenal disorders involve the overproduction or underproduction of different hormones.

Symptoms of Addison’s disease typically include:

  • Weight loss
  • Weakness
  • Extreme fatigue
  • Nausea and/or vomiting
  • Low blood pressure
  • Patches of darker skin
  • Craving for salt
  • Dizziness upon standing
  • Depression

Symptoms of adrenal cancer (more specifically called adrenal cortical cancer or adrenocortical carcinoma) can include:

  • Weight gain
  • Fluid retention (resulting in bloating)
  • Unusual excess growth of facial or body hair
  • Abdominal pain or a feeling of fullness (if the tumor is pressing on other nearby organs)

Common symptoms of Cushing’s syndrome include:

  • Upper body obesity, round face and neck, and thinning arms and legs
  • Skin problems, such as acne or streaks of discoloration on the abdomen or underarms
  • High blood pressure
  • Muscle and bone weakness
  • Irritability, moodiness, or depression
  • High blood sugar
  • Slow growth rates in children
  • In women, increased growth of facial or body hair and menstrual irregularities
  • In men, reduced fertility and libido (sex drive)

Symptoms of congenital adrenal hyperplasia (CAH) can range from mild to serious, depending on the severity of the condition. Milder symptoms of CAH may include:

  • Early signs of puberty
  • Acne
  • Shorter than average final height
  • In women, irregular menstrual periods and possible trouble getting pregnant; excess facial hair

More severe CAH symptoms may include (in addition to the milder symptoms above):

  • Dehydration
  • Low blood pressure
  • Low blood sugar levels
  • Difficulty keeping enough salt in the body
  • Altered development of the external genitalia in girls (this is noted at birth and may require corrective surgery)
  • In men, benign testicular tumors and infertility

How Adrenal Gland Disorders Are Diagnosed

Testing for adrenal gland disorders is usually done by an endocrinologist. You will probably have your blood, urine, and/or saliva checked for levels of the hormones secreted by the adrenal gland. The doctor may also order one or more imaging tests of your adrenals such as an CT scan, MRI, or nuclear scan. If your health care provider believes your adrenal gland problem is due to a malfunction in another gland (a “secondary cause”), such as
a pituitary tumor, you might also need testing done on your pituitary gland.

The severe form of congenital adrenal hyperplasia (CAH) is most commonly identified during newborn screening.

Adrenal Gland Disorder Treatment

Treatment for an adrenal gland disorder will vary depending on which disorder you have and how severe it is. Your treatment may include medication, surgery, or both. Specific treatments used for adrenal disorders include:

  • Medication to stop the excess production of hormones
  • Hormone replacement medication
  • Surgery to remove tumors in the adrenal gland
  • Surgery to completely remove one or both of the adrenal glands
  • Minimally invasive surgery (done through the nostrils) to remove tumors in the pituitary gland
  • For cancer, surgery, radiation, or chemotherapy

Adrenal Gland Disorder Outlook

With the right therapies and medical care, many people with adrenal gland disorders live long, healthy lives—though in some cases (such as Addison’s disease) you may need to take medication for life. Talk with your doctor about the outlook for your specific condition and what steps you can take to achieve the best positive outcome.

Additional reporting contributed by Jamie Kopf.

Notes: This article was originally published June 5, 2009 and most recently updated January 5, 2022 .