Antidiuretic Hormone(ADH) – Functions, Regulations, Disorders and Levels

Antidiuretic Hormone (ADH) is an essential hormone in the human body. Sometimes ADH is also known as Vasopressin. Vasopressin is made up of a combination of two words. Vaso + Pressin. Where Vaso means something which is related to blood vessels. Pressin means to squeeze something. ADH got this name from its nature. It is used when there is a lack of water in the human body. It regulates kidney function for conserving the water crisis in the body. It is called ADH when it secretes low in concentration. When concentration is high in amount then it is called Vasopressin. ADH helps to control various life-threatening conditions. Also, it helps to control the bleeding abnormality & septic shocks. The function of ADH in a simple one line is, that it helps to control the osmolarity in blood.

Synthesis of ADH

We often say that the ADH hormone secretes from the Posterior portion of the pituitary gland. But secretion is different from the production or manufacturing. Practically, ADH is produced in the hypothalamus. Beneath the hypothalamus, there is a pituitary gland present. In the hypothalamus, ADH is produced & it comes down to the pituitary gland & stored there. If there is any need to secrete the hormone then it comes out from the pituitary gland & mixed with blood. Now, if we look into the deep process of synthesis of ADH hormone, then we come to know that the main producer of ADH hormones is some neurons. In the hypothalamus, there are supraoptic neurons are present. From this particular type of neuron, the ADH is produced. Then via the hypothalamus, it comes down to the pituitary gland. The pituitary gland works as the storehouse for ADH hormones. But every time ADH does not produce. When there is a lack of quantity in the pituitary gland then only it is produced.

Release Of ADH

Hypothalamus is situated in the 3rd ventricle of our brain. There are many bold vessels are present. Though they are not directly connected with the hypothalamus. When there is a sudden low concentration of water in our blood system, the hypothalamus is alerted by these blood vessels. These blood vessels provide a signal to the hypothalamus that there is a low concentration of water in the body. Now, in the hypothalamus, there are two specific receptors are present. They are Organum Vasculosum & Subfornical Organ. These two receptors take the responses from the blood vessels. Then they command the Supra optic neurons to secrete ADH hormones if there is a low amount of ADH stored in the Pituitary gland. Then after the production of the ADH hormone, it comes down to the posterior pituitary gland & secretes from there. But if there is a sufficient amount of ADH stored in the posterior pituitary gland, then these receptors command the pituitary gland to release the ADH hormones. In this way, the whole system works.

Structure/Composition of ADH

ADH is a hormone that is non-peptide in nature. ADH is made with a signal peptide, neurophysin II & a glycoprotein. ADH is derived from preprohormone, often called prepropressophysin. The signal peptide portion is produced from various Golgi Apparatus.

Importance of ADH

ADH hormone is used for the hearse environment situation. Suppose, if anyone is trapped in a desert-like environment. In that situation, due to excess heat, the maximum amount of water is vaporized as sweat. Sometimes, the human body excretes water from its body in a different manner. But the point is that in such a situation, the human body loses water rapidly. It is said that without food human body can survive up to 7 days. But without water, within 3 days the body fails to respond & eventually death occurs. 

In this type of scenario, ADH comes into action. It first gains the signal that there is a lack of water quantity in the body. After it is mixed up with the blood it directly affects the kidney. Nephrons are stimulated by ADH hormones. At nephrons, the outermost part of it is sensible of water. ADH hormones regulated that part & from the kidney, the excess water comes back to the blood vessels again. Normal time, the excess water will remove from the body as the urine. But in this type of case, the excess water returns back to the body & mixes up with the blood. Hence, the water level in the blood tries to make a balance. 

Function of ADH

• Maintaining Body Normal Rhythm-ADH hormone is used to regulate the circadian rhythm of the body. If the circadian rhythm does not work properly then the function of the heart may get disturbed. Hence, much more difficult situations may get arise.
• Self-Regulation-ADH is known for its self-regulation. It is responsible for Homeostasis. Homeostasis is a biological term that normally means self-regulation. Homeostasis means to regulate itself in a way that in bad situations it can able to stay safe.
• Maintaining Cellular Performance-For every cell water is necessary. But if there is any crisis in water level in the body, every cell start malfunctioning. As ADH helps to maintain the water level balance in the body, it helps every cell of the body to work normally.
• Influence On Kidney-ADH maintain & monitor the volume of water in the body. If there is any low quantity of water in the body, it takes the water in the urine & returns it back to the blood. It regulates the nephrons of the kidney & from its exterior part it absorbs the excess water & returns them back to the blood.
• Maintaining Blood Pressure-It acts on blood vessels & maintain the blood pressure in the body.

Regulation Of ADH

1. When the blood pressure is decreased, it is detected by the blood vessels. It alerts the ADH hormone secretion in the body.
2. If the concentration of salt increases in the blood vessels, it stimulates the pituitary gland to secrete the ADH hormones. The high amount of alcohol consumption may prevent ADH production in the body. In these cases, urine produced high in quantity & causes dehydration
3. If there is a low concentration of water in the body, this may stimulate the pituitary gland to secrete the ADH hormones.

Disorder With ADH

ADH hormones disorder can happen either for low-level or high-level ADH hormone secretion. Following are some symptoms of ADH hormone disorder:

1. Change in appetite
2. Genetic disorder
3. Head injuries
4. Insomnia
5. Infertility
6. Autoimmune disorder

Conceptual Questions

Question 1: What are the factors that stimulate ADH hormones?

Answer:

Many factors are there which stimulate the ADH hormones secretion. But among them, the two most important are changes in osmotic pressure & volume status of the blood.

Question 2: Is the ADH level secretion decreases with age?

Answer:

With aging, ADH level secretion decreases at night. In old age, ADH secretes less an amount in the daytime. That is why it should decrease its level of a secretion at night to maintain a balance.

Question 3: At which part of the nephrons is the ADH hormones directly affecting?

Answer:

In the collecting duct of the nephrons, the ADH hormones effects most. There it absorbs the excess water from the urine & makes it available in the body.

Question 4: Where is ADH synthesis?

Answer:

ADH synthesis in the hypothalamus. It is situated in the 3rd ventricle of our brain. Mainly, Supra Optic neurons are the main producer of the ADH hormones.

Question 5: From where is ADH secretes?

Answer:

ADH secretes from the posterior pituitary gland. It acts as the storehouse of the ADH hormones. After synthesized from the hypothalamus, ADH is stored in the posterior pituitary gland. When there is a need to release the hormone, it secretes from the pituitary gland.