Hormones of the Adrenal Glands
The role of the adrenal glands in your body is to release certain hormones directly into the bloodstream. Many of these hormones have to do with how the body responds to stress, and some are vital to existence. Both parts of the adrenal glands — the adrenal cortex and the adrenal medulla — perform distinct and separate functions.
Each zone of the adrenal cortex secretes a specific hormone. The key hormones produced by the adrenal cortex include:
Cortisol
Cortisol is a glucocorticoid hormone produced by the zona fasciculata that plays several important roles in the body. It helps control the body’s use of fats, proteins and carbohydrates; suppresses inflammation; regulates blood pressure; increases blood sugar; and can also decrease bone formation.
This hormone also controls the sleep/wake cycle. It is released during times of stress to help your body get an energy boost and better handle an emergency situation.
How Adrenal Glands Work to Produce Cortisol
Adrenal glands produce hormones in response to signals from the pituitary gland in the brain, which reacts to signaling from the hypothalamus, also located in the brain. This is referred to as the hypothalamic pituitary adrenal axis. As an example, for the adrenal gland to produce cortisol, the following occurs:
The hypothalamus produces corticotropin-releasing hormone (CRH) that stimulates the pituitary gland to secrete adrenocorticotropin hormone (ACTH).
ACTH then stimulates the adrenal glands to make and release cortisol hormones into the blood.
Normally, both the hypothalamus and the pituitary gland can sense whether the blood has the appropriate amount of cortisol circulating. If there is too much or too little cortisol, these glands respectively change the amount of CRH and ACTH that gets released. This is referred to as a negative feedback loop.
Excess cortisol production can occur from nodules in the adrenal gland or excess production of ACTH from a tumor in the pituitary gland or other source.
Aldosterone
This mineralocorticoid hormone produced by the zona glomerulosa plays a central role in regulating blood pressure and certain electrolytes (sodium and potassium). Aldosterone sends signals to the kidneys, resulting in the kidneys absorbing more sodium into the bloodstream and releasing potassium into the urine. This means that aldosterone also helps regulate the blood pH by controlling the levels of electrolytes in the blood.
DHEA and Androgenic Steroids
These hormones produced by the zona reticularis are weak male hormones. They are precursor hormones that are converted in the ovaries into female hormones (estrogens) and in the testes into male hormones (androgens). However, estrogens and androgens are produced in much larger amounts by the ovaries and testes.
Epinephrine (Adrenaline) and Norepinephrine (Noradrenaline)
The adrenal medulla, the inner part of an adrenal gland, controls hormones that initiate the flight or fight response. The main hormones secreted by the adrenal medulla include epinephrine (adrenaline) and norepinephrine (noradrenaline), which have similar functions.
Among other things, these hormones are capable of increasing the heart rate and force of heart contractions, increasing blood flow to the muscles and brain, relaxing airway smooth muscles, and assisting in glucose (sugar) metabolism. They also control the squeezing of the blood vessels (vasoconstriction), helping maintain blood pressure and increasing it in response to stress.
Like several other hormones produced by the adrenal glands, epinephrine and norepinephrine are often activated in physically and emotionally stressful situations when your body needs additional resources and energy to endure unusual strain.
Adrenal Gland Disorders
The two common ways in which adrenal glands cause health issues are by producing too little or too much of certain hormones, which leads to hormonal imbalances. These abnormalities of the adrenal function can be caused by various diseases of the adrenal glands or the pituitary gland.
Adrenal Insufficiency
Adrenal insufficiency is a rare disorder. It may be caused by disease of the adrenal glands (primary adrenal insufficiency, Addison’s disease) or by diseases in the hypothalamus or the pituitary (secondary adrenal insufficiency). It is the opposite of Cushing syndrome and is characterized by low levels of adrenal hormones. The symptoms include weight loss, poor appetite, nausea and vomiting, fatigue, darkening of skin (only in primary adrenal insufficiency), abdominal pain, among other.
The causes of primary adrenal insufficiency may include autoimmune disorders, fungal and other infections, cancer (rarely), and genetic factors.
Although adrenal insufficiency usually develops over time, it can also appear suddenly as an acute adrenal failure (adrenal crisis). It has similar symptoms, but the consequences are more serious, including life-threatening shock, seizures, and coma. These may develop if the condition is left untreated.
Congenital Adrenal Hyperplasia
Adrenal insufficiency can also result from a genetic disorder called congenital adrenal hyperplasia. Children who are born with this disorder are missing an essential enzyme necessary to produce cortisol, aldosterone or both. At the same time, they often experience excess of androgen, which may lead to male characteristics in girls and precocious puberty in boys.
Congenital adrenal hyperplasia can remain undiagnosed for years depending on the severity of the enzyme deficiency. In more severe cases, infants may suffer from ambiguous genitalia, dehydration, vomiting and failure to thrive.
Overactive Adrenal Glands
Sometimes, adrenal glands may develop nodules that produce too much of certain hormones. Nodules 4 centimeters or larger and nodules that show certain features on imaging increase suspicion for malignancy. Both benign and cancerous nodules may produce excessive amounts of certain hormones, which is referred to as a functional nodule. Functional tumors, malignant tumors or nodules greater than 4 centimeters are recommended to be referred for surgical evaluation.
Excess of Cortisol: Cushing Syndrome
Cushing syndrome results from excessive production of cortisol from the adrenal glands. The symptoms may include weight gain and fatty deposits in certain areas of the body, such as the face, below the back of the neck called a buffalo hump and in the abdomen; thinning arms and legs; purple stretch marks on the abdomen; facial hair; fatigue; muscle weakness; easily bruised skin; high blood pressure; diabetes; and other health issues.
Excess cortisol production can also be triggered by overproduction of ACTH by a benign tumor in the pituitary gland or tumor elsewhere in the body. This is known as Cushing Disease. Another common cause of Cushing syndrome is excessive and prolonged consumption of external steroids, such as prednisone or dexamethasone, which are prescribed to treat many autoimmune or inflammatory diseases (e.g., lupus, rheumatoid arthritis, asthma, inflammatory bowel disease, multiple sclerosis, etc.)
Excess of Aldosterone: Hyperaldosteronism
Hyperaldosteronism results from overproduction of aldosterone from one or both adrenal glands. This is characterized by increase in blood pressure that often requires many medications to control. Some people can develop low potassium levels in the blood, which can cause muscle aches, weakness and spasms. When the cause is adrenal oversecretion, the disease is called Conn syndrome.
Excess of Adrenaline or Noradrenaline: Pheochromocytoma
Pheochromocytoma is a tumor that results in excess production of adrenaline or noradrenaline by the adrenal medulla that often happens in bursts. Occasionally, neural crest tissue, which has similar tissue to the adrenal medulla, may be the cause of overproduction of these hormones. This known as a paraganglioma.
Pheochromocytomas may cause persistent or sporadic high blood pressure that may be difficult to control with regular medications. Other symptoms include headaches, sweating, tremors, anxiety and rapid heartbeat. Some people are genetically predisposed to developing this type of tumor.
Adrenal Cancer
Malignant adrenal tumors (adrenal cancer), such as adrenocortical carcinoma, are rare and often have spread to other organs and tissues by the time they are diagnosed. These tumors tend to grow fairly large and can reach several inches in diameter.
Cancerous adrenal tumors can be functional and release excess of one or more hormones accompanied by corresponding symptoms, as listed above. Patients may also experience abdominal pain, flank pain or a feeling of abdominal fullness, especially when the adrenal tumor gets very large.
Not all cancers found in adrenal glands originate from the gland itself. The majority of adrenal tumors are metastasis, or cancer spread, from another primary tumor elsewhere in the body.
Adrenal Gland
Your adrenal glands are endocrine glands located on top of your kidneys. They produce many important hormones, including cortisol, aldosterone and adrenaline. The adrenal hormones help regulate several bodily functions including metabolism, blood pressure and your body's response to stress.
Overview
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:
- Hypothalamus.
- Pituitary gland.
- Thyroid.
- Parathyroid glands.
- Adrenal glands.
- Pineal gland.
- Pancreas.
- Ovaries.
- Testes.
Function
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:
- Hypothalamus.
- Pituitary gland.
- Kidneys.
- 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.
Anatomy
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.
Care
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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