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Aldosterone, Hyperaldosteronism, and Hypoaldosteronism

Updated on April 18, 2017
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Linda Crampton is a teacher with a first class honors degree in biology. She writes about human biology and the scientific basis of disease.

The adrenal gland is located on top of the kidney. Both organs are surrounded by a fat layer and a fibrous capsule. We have two kidneys and two adrenal glands.
The adrenal gland is located on top of the kidney. Both organs are surrounded by a fat layer and a fibrous capsule. We have two kidneys and two adrenal glands. | Source

What Is Aldosterone?

Aldosterone is a hormone made by the adrenal glands. When it's released into the bloodstream, it increases the sodium level in the blood and decreases the potassium level. These changes cause blood volume and blood pressure to increase.

The amount of aldosterone that enters the blood changes as internal conditions in the body change. The hormone adjusts blood volume and blood pressure as necessary to help our body function properly.

Hyperaldosteronism is a disorder in which too much aldosterone is made. The excess hormone causes the blood pressure to increase beyond a healthy level. In hypoaldosteronism, not enough aldosterone is made, which results in a blood pressure that is too low.

Functions of the adrenal gland
Functions of the adrenal gland | Source

The outer layer of the adrenal gland is called the cortex and the inner layer is called the medulla. Each layer secretes different chemicals, as shown in the diagram above.

The Adrenal Glands and the Kidneys

There are two adrenal glands, one on top of each kidney. The right adrenal gland (from the owner's point of view) has a triangular shape. The left one is shaped like a half-moon. Aldosterone is made by the outer layer of the adrenal glands, which is known as the adrenal cortex.

Sodium Ion Reabsorption

Sodium ions are filtered out of the blood and into the kidney tubules (nephrons). If the ions stay in the nephrons, they are transported to the urinary bladder and released from the body in urine. Some sodium ions are reabsorbed into the blood vessels around the nephrons and don't reach the urinary bladder, however. One function of aldosterone is to increase sodium ion reabsorption from the nephrons.

Whenever sodium ions are reabsorbed into the bloodstream, the reabsorption of water molecules follows. The water increases the volume of the blood, which in turn increases blood pressure. Therefore aldosterone indirectly increases both blood volume and blood pressure.

Potassium Ion Excretion

Aldosterone also regulates the concentration of potassium ions in the blood. As sodium ions are reabsorbed into the blood vessels around the nephron, potassium ions are transported in the opposite direction—from the blood vessels into the nephron—and are then excreted in the urine. Aldosterone increases this transport and excretion of potassium ions.

Summary of Aldosterone's Effects

Concentration of sodium ions in blood goes UP

Blood volume and pressure go UP

Concentration of potassium ions in blood goes DOWN

In human biology, the prefix hyper means that something is in excess. Hyperaldosteronism means that the aldosterone level in the blood is too high, for example. The prefix hypo means that the amount of something is too low. For example, people with hypoaldosteronism don't have enough aldosterone in their blood.

Primary Hyperaldosteronism

Hyperaldosteronism is an abnormally high level of aldosterone in the body. It can arise due to a problem within the adrenal glands (primary hyperaldosteronism) or to a problem which originates outside the adrenal glands (secondary hyperaldosteronism).

Primary hyperaldosteronism is also called Conn's syndrome. It's often caused by a tumor in one of the adrenal glands. The tumor is usually an adenoma and is benign, meaning that it stays in one place and is non-cancerous. Sometimes the term Conn's syndrome is reserved for primary hyperaldosteronism produced by an adenoma. Rarely, the condition is caused by a cancerous tumor in an adrenal gland.

Primary hyperaldosteronism may also develop due to idiopathic adrenal hyperplasia. “Hyperplasia” means increased cell production, which causes enlargement of an organ or gland, and “idiopathic” means that there is no known cause for the change. Generally both the adrenal glands undergo hyperplasia.

It was once thought that Conn's syndrome was a rare disorder. Now doctors are beginning to think that it is more common than previously believed and is responsible for some cases of hypertension (high blood pressure). The condition is most common in adults than children. There is a rare inherited form of the disorder called familial hyperaldosteronism which may appear in childhood, however.

Conn's Syndrome

Secondary Hyperaldosteronism

Secondary hyperaldosteronism is caused by a factor outside the adrenal glands that stimulates the production of aldosterone.

One possible cause of secondary hyperaldosteronism is an increase in renin due to a kidney disorder. Renin is an enzyme that is made by the kidneys. The enzyme is released into the bloodstream when there is low blood pressure caused by low blood volume. It's also released when the concentration of sodium ions in the nephrons is too high and the concentration in the blood is too low.

Renin triggers a series of reactions that stimulate aldosterone release. The aldosterone returns conditions to normal by stimulating sodium ion reabsorption into the body and increasing blood volume (and therefore blood pressure). If too much renin is produced, the level of aldosterone will increase too.

Secondary hyperaldosteronism may also develop as part of some other diseases, such as cirrhosis of the liver and congestive heart failure.

Seek Medical Advice When Necessary

Anyone who has unexplained symptoms resembling those of an aldosterone problem should visit a doctor. The symptoms listed below can be caused by a variety of health problems. A doctor's expertise is needed for a diagnosis and treatment recommendations.

Possible Symptoms of Hyperaldosteronism

People with too much aldosterone in their bodies often develop high blood pressure. This disorder may cause no additional symptoms. It may produce problems such as headaches, vision problems, and an irregular heartbeat, however.

Some patients with hyperaldosteronism develop symptoms of a potassium deficiency. A low potassium level is known as hypokalemia. A mild case of hypokalemia may cause no symptoms. If symptoms do appear, they may include muscle weakness, numbness, tingling, and cramps. The patient may also experience an irregular heartbeat. If the disorder lasts for a long time, there may be excessive urine production.

Licorice (or liquorice) can raise blood pressure.
Licorice (or liquorice) can raise blood pressure. | Source

Licorice and Hyperaldosteronism-Like Symptoms

Licorice doesn’t cause hyperaldosteronism, but it can produce similar effects. True licorice contains a sweet substance called glycyrrhizin, which affects the body in a similar way to aldosterone. It raises the level of sodium ions in the blood, increases blood volume, and increases blood pressure. It also lowers the level of potassium ions in the blood.

Most “licorice” bought in candy stores actually contains very little or no licorice and is flavored with other substances, such as anise oil. This is safe to eat as far as changing blood pressure is concerned. However, herbal teas containing licorice, real licorice candies, and other products containing licorice root should be used with caution.

Possible Treatments

A doctor will likely have a variety of treatments to offer someone with hyperaldosteronism. An adrenal gland tumor may be surgically removed. Drugs may be given to block the action of excess aldosterone. Potassium supplements may be prescribed for temporary use before the aldosterone level returns to normal. The treatment of other disorders that are producing the hyperaldosteronism may also return the hormone to a normal level.

A stained section of an adrenal gland
A stained section of an adrenal gland | Source

Hypoaldosteronism

The hormones released by the adrenal cortex belong to three classes of steroid chemicals: the mineralocorticoids (such as aldosterone), the glucocorticoids (such as cortisol) and the androgens (a group of hormones that produce male characteristics).

A low blood level of aldosterone is known as hypoaldosteronism. Aldosterone deficiency is most often accompanied by a deficiency of other hormones made by the adrenal cortex in a condition called primary adrenal insufficiency, also known as Addison’s disease. In this disorder, the adrenal cortex fails to produce enough of one or more of its hormones. Primary adrenal insufficiency develops due to damage to the adrenal cortex.

There are other possible causes of hypoaldosteronism. Kidney damage may lead to decreased renin production, which may then result in decreased production of aldosterone. NSAIDs (nonsteroidal anti-inflammatory drugs) and certain diuretics have been found to lower the aldosterone level in the blood of some people. Diabetics are more likely to develop hypoaldosteronism than non-diabetics.

Hypoaldosteronism may also be caused by some autoimmune diseases. Our immune system normally attacks bacteria, viruses, and other agents that can cause disease. In an autoimmune condition, the immune system mistakenly attacks the body's own tissues. If these tissues are directly or indirectly involved in aldosterone production, a problem may develop.

Aldosterone Action in Detail

Possible Symptoms of Hypoaldosteronism

Possible signs of hypoaldosteronism include a high blood potassium level (hyperkalemia), low blood sodium level, and low blood pressure. Each of these conditions can produce its own set of symptoms, some of which are listed below. (As in hyperaldosteronism, the symptoms may be caused by other disorders. A doctor should be consulted if the symptoms are present.)

  • Hyperkalemia can cause an irregular heartbeat or a slow heart rate, muscle fatigue, and weakness.
  • A low concentration of sodium ions in the blood is known as hyponatremia. Symptoms can include fatigue, confusion, muscle twitches, weakness, nausea, and a headache
  • Very low blood pressure can cause symptoms such as dizziness, lightheadedness, fainting (technically known as syncope), blurred vision, nausea, and cold, pale skin.

An aldosterone molecule has a complex structure and is an important substance
An aldosterone molecule has a complex structure and is an important substance | Source

Possible Treatments for Hypoaldosteronism

Possible treatments for hypoaldosteronism include dealing with the health problems that are interfering with aldosterone production, replacing medications that are lowering the blood level of the hormone, and the use of mineralocorticoid medications to replace the missing aldosterone.

Aldosterone is a very useful molecule, but it can cause big problems when it is in excess or at an inadequate level. Fortunately, doctors have ways to help most people with these problems.

References

Primary Hyperaldosteronism facts from the Mayo Clinic

Hyperaldosteronism information from the Merck Manual (the online version of a leading medical textbook)

Adrenal Insufficiency and Addison's Disease information from the National Institutes of Health

© 2011 Linda Crampton

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    • A.A. Zavala profile image

      Augustine A Zavala 6 years ago from Texas

      I had no idea about the licorice connection to the adrenals. Thank you for sharing.

    • crystolite profile image

      Emma 6 years ago from Houston TX

      Great teaching in here that is very very useful,thanks for impacting some knowledge in me.

    • AliciaC profile image
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      Linda Crampton 6 years ago from British Columbia, Canada

      Thank you for your comment, A.A. Zavala.

      Hello, crystolite. It's nice to meet you. Thanks for commenting.

    • RTalloni profile image

      RTalloni 6 years ago from the short journey

      Interesting info to keep in mind. This is a great reference for anyone in need. Voted up.

    • AliciaC profile image
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      Linda Crampton 6 years ago from British Columbia, Canada

      Thank you for the comment and vote, RTalloni!

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