Aldosterone Function
Adrenal glands
On top of each kidney lies the adrenal gland. The gland is made of an outer cortex and an inner medulla. The hormones adrenaline, noradrenaline, and dopamine are produced by the inner layer. The other layer is the steroid producing layer which is the outer cortex. Mineralocorticoids and glucocorticoids are produced by this layer. The glucocorticoid is responsible for utilizing the glucose in the metabolism process and storing it whereas minerals in the blood are retained by the mineralocorticoids. One such mineralocorticoid is aldosterone. Since they help the body to retain minerals such as sodium and chlorine and absorb it hence it is named, mineralocorticoid. On the filtration system of the kidneys the aldosterone directly acts so that it can reclaim salts. The function of the kidney is to remove excess water, electrolytes, and purify the metabolic wastes. The blood can become toxic if the waste is not removed and the blood is not purified. Hence in case of kidney failure people go for dialysis.
What is aldosterone?
Even though not many are familiar with this hormone, it plays an important role in our cardiovascular health. The cortex of the adrenal gland produces aldosterone. The ability of the body to regulate blood pressure is affected by the aldosterone. Signals are sent to the kidney and colon and the amount of sodium sent in the blood increases or the amount of potassium excreted in the urine increases. Also, aldosterone causes reabsorption of water along with sodium by the blood so that the blood volume can increase. The action of aldosterone is responsible for increasing or decreasing the blood vessels, by doing this the electrolyte level and pH also is indirectly maintained.
Two other hormones are associated with aldosterone and these are rennin and angiotensin. Together they create a system known as rennin angiotensin system. When the blood flow to the kidneys decreases this system gets activated. This happens mostly when after a serious injury or hemorrhage the blood pressure or the blood volume significantly reduces. For the production of angiotensin, renin is very important since it causes aldosterone to be released. The level of renin will fall once the body is rehydrated and in the blood normal salt level is attained. The fall in the renin level will cause a further fall in the aldosterone level.
The adrenal gland produces the hormone aldosterone which is also known as a mineralocorticoid. The body is able to retain sodium and water due to aldosterone and it also helps in excretion of potassium which is responsible for high blood pressure. There is a pattern of secretion of aldosterone, towards the end of the sleep phase its level increases. The increase in aldosterone production is signaled by the high level of potassium in the blood. The working of the hormone aldosterone and atrial natriuretic peptide is quite the opposite. The heart produces atrial natriuretic peptide. It lowers the blood pressure by excreting sodium. Diseases can develop if the level of aldosterone with respect to angiotensin aldosterone system goes too high or too low. This system is responsible for regulating the fluids in the body and our blood pressure.
When low blood pressure is recognized by the kidney cells then angiotensin I is produced by a cascade of events. This angiotensin I is converted into angiotensin II by angiotensin-converting enzyme. The adrenal gland is stimulated to further produce aldosterone by angiotensin I. Taking ACE inhibiting drugs will lower the blood pressure which is caused by lowering the aldosterone level by blocking the angiotensin-converting enzyme.
Conditions associated with aldosterone
High levels of aldosterone can cause a range of health conditions such as high blood pressure, autoimmune disease cardiovascular disease, chronic kidney disease, osteoporosis, and Conn syndrome. When the level of aldosterone is low the conditions associated with it are chronic inflammation, aging, hearing loss associated with advanced age, and Addison’s disease.
Positive effects of aldosterone
Viral infections such as EBV can be controlled by the CD + cells which are increased by aldosterone. Hence people with chronic fatigue syndrome can potentially benefit from it. For some types of inflammation such as uveitis too aldosterone can be beneficial. In the blood cells it blocks Nf-kB induced TNF alpha. The body is able to make cysteine dioxygenase with the help of aldosterone. For the sulfation pathway of phase 2 detoxification this process is very essential. The enzyme that converts cysteine to sulfate can be decreased by chronic inflammation due to which the level of cysteine increases and the level of sulfate reduces.
The negative effects of aldosterone
Overall, a high level of aldosterone is not good. The master control switch of inflammation is increased by IL-6, IL-1b, and TNF. Also, Nf-kB is induced by aldosterone. For autoimmune diseases, chronic inflammation, and cardiovascular disease it is bad to have Th 17 immunity which is promoted by aldosterone.
Also, according to some researchers they believe that onset of autoimmune diseases can be promoted by aldosterone. For the heart especially aldosterone is bad. It causes an increase in vessel dysfunction, oxidative stress, inflammation, vessel dysfunction, fibrosis, and in our blood vessels prevent regeneration of new cells.
The hippocampal BCB1 receptor binding site can be reduced significantly if one is exposed to a high level of aldosterone and cortisol for a prolonged duration. This lowers the cannabinoid function. Magnesium and potassium in the body can get depleted due to high aldosterone. Also, the body can get depleted of calcium if the amount of aldosterone, leading to osteoporosis. One major cause of high blood pressure is high aldosterone.
What can go wrong with aldosterone?
In healthy individuals the blood pressure is naturally regulated and controlled by the angiotensin aldosterone system. However, the function of aldosterone can be impacted by a too high or too low level of aldosterone. A condition known as hyperaldosteronism occurs in individuals with a high level of aldosterone. This mostly occurs when on the adrenal gland there is a small benign tumor. This condition can cause the blood volume to abnormally increase, potassium levels to decrease, and high blood pressure. One can even have a low aldosterone level; this is caused by primary adrenal insufficiency. In this condition potassium level increases, one may experience lethargy and low blood pressure.
The production of aldosterone can also be affected by genetic mutations. This genetic disorder is quite rare and such patients will show symptoms similar to symptoms that occur in primary adrenal insufficiency, the only difference is that the symptoms experienced may not be a severe one.
Role of aldosterone in renin angiotension system
Renin, angiotensin I, angiotensin II, and angiotensin-converting enzyme are the important members of this system. For any reason when there is a drop in the blood pressure then this change is detected by the special cells in the kidney and in the blood renin is released. The blood pressure is not affected by renin alone; in fact, the inactive forms of angiotensin is changed to angiotensin I by this renin. The blood pressure can be altered by angiotensin I to some extent but it cannot cause large changes. Hence most of the angiotensin I is changed to angiotensin II which is able to cause large changes in the blood pressure. This conversion takes place in the lungs with the help of the angiotensin-converting enzyme. This hormone angiotensin II is so strong that it can cause blood pressure to increase by directly acting on the blood vessels. Also, another function associated with it is that it can stimulate the release of aldosterone which is a very powerful vasoconstrictor that can cause significant changes in the blood pressure. Also, this hormone is a very important one since the baseline filtering activity of the kidneys can be actually changed by it. Also, it can over a period of time cause an increase in the body fluid by retaining salt and water in the kidneys which further causes an increase in the blood pressure.
After some time angiotensin I, angiotensin II and aldosterone are broken into small molecules. Short term variations in the blood pressure are brought about by the renin-angiotensin system as a whole. The system gets activated when the blood pressure suddenly drops, such as due to an injury or some other reason there is blood loss but even smaller blood pressure fluctuations even can stimulate the system.
The baseline level of activity of the renin-angiotensin system is constant as it can regulate blood pressure for the long term. It means that over the long term the blood pressure can be kept steady by the constant activity of this system but when quick response is required there can be a sudden burst of activity.
Many articles have documented the importance of this system in regulating blood pressure. Since many factors are associated with this system hence the renin-angiotensin system gets lots of attention. Renin-angiotensin system is associated with high blood pressure; it helps one to understand that why to normal blood pressure treatment one is not able to respond well to understand that why more complications are developed in people with high blood pressure.
What controls the aldosterone?
In the cortex of the adrenal gland the hormone aldosterone is produced. The gland is placed above the kidneys. Regulating the blood pressure is the central role of this hormone, for this it acts on the colon and the kidneys. There are many hormones associated with the renin-angiotensin system of which aldosterone is one part. Reduction in the blood flow in the kidneys causes activation of this system. Chemical reactions take place due to enzyme renin whose end result is the production of angiotensin II which causes the release of aldosterone. Thus the reabsorption of salt and water from the kidneys in the blood increases, blood volume increase, and normal salt level and blood pressure is restored.
Questions to ask your doctor
You can talk to your doctor about aldosterone if you have issues in maintaining the blood pressure of the body. If lifestyle changes are not helping, then you can ask the doctor whether the hormone is causing these changes. The doctor will check the hormone level and accordingly treat you.
Many conditions are associated with abnormal aldosterone functions. One such is Conn syndrome which happens when there is too much of aldosterone. It causes high blood pressure, potassium level is low and blood volume is more. Addison’s disease can develop due to insufficient cortisol and aldosterone in the body. It causes low blood pressure, feeling exhausted, and high potassium levels. A common form of Conn syndrome is secondary aldosteronism which develops due to excess of the hormone aldosterone. It causes low potassium levels and high blood pressure. Another condition associated with aldosterone is Cushing syndrome due to excess of cortisol and aldosterone. It causes the skin to become thin, purple, or pink stretch marks develop, and more fat is present around the neck, face, and upper back.
An aldosterone test is ordered by the doctor so that the doctor can determine whether the person has any condition. Along with this test the doctor may also order renin and cortisol blood tests. Conn syndrome or hyperaldosteronism is diagnosed if the level of aldosterone is high, renin is low and cortisol level is normal. Secondary aldosteronism is diagnosed if the level of aldosterone and renin is high. Addison’s disease is diagnosed if the level of cortisol and aldosterone is lower and renin is higher. Cushing syndrome is diagnosed if the level of aldosterone and renin is lower and cortisol is higher.
Article resources:
http://www.yourhormones.info/hormones/aldosterone/
https://www.hormone.org/hormones-and-health/hormones/aldosterone
https://www.ncbi.nlm.nih.gov/books/NBK470339/
https://labtestsonline.org/tests/aldosterone-and-renin
