ADH (Antidiuretic Hormone)

What is ADH?

ADH, also known as arginine vasopressin, is a hormone produced by the hypothalamus and stored in the posterior pituitary gland. It is made up of special nerve cells found at the base of the hypothalamus. The hormone is transported to the pituitary gland via axons, where it is released into the bloodstream. It regulates and balances the amount of water in the blood.

The hypothalamus contains osmotic sensors that react to the concentration of sodium, potassium, carbon dioxide, and chloride. When the blood pressure is very low these osmotic sensors and baroreceptors intimate the kidneys to store or release water to maintain the concentration of these substances.

Role Of ADH

  • It acts on the kidneys and the blood vessels and functions to control the blood pressure. Higher concentrations of ADH constrict the blood vessels which increases the blood pressure.
  • It allows the water in the urine to be taken back in a specific area in the kidney and thus reduces the amount of water excreted through the urine thereby conserving the volume of the fluid in the body.
  • It is mainly responsible for homeostasis.

Also read: Regulation of Kidney Function

Regulation Of ADH

The release of ADH into the bloodstream is regulated by a number of factors:

  • The decrease in the blood volume or blood pressure is detected by the large blood vessels and the receptors present in the heart which stimulate the release of ADH.
  • The increase in the concentration of salts in the bloodstream also controls the secretion of ADH which is identified by special nerve cells in the hypothalamus.
  • Alcohol prevents the release of ADH. This causes dehydration and an increase in urine production.

High Levels of ADH

If the levels of ADH are higher, the water is retained by the kidney in the body. When excess ADH is released when not required, the blood gets diluted due to excess water retention. The salt concentration in the blood thus decreases. High levels of ADH may be caused due to the side-effects of drugs, lung diseases, etc. Increased ADH is associated with leukaemia, lymphoma, bladder cancer, brain cancer, etc.

Low Levels of ADH

In this condition, a lot of water is excreted by the kidneys. This increases urine volume and lowers blood pressure. Low levels of ADH indicate primary polydipsia and damage to the hypothalamus or pituitary gland. Diabetes insipidus is related to low levels of ADH.

Also read: Hormones in Animals

For more information on ADH (Antidiuretic Hormone) and other endocrine hormones, visit BYJU’S website or download BYJU’S app.

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