12th April 2024

Antidiuretic hormone (ADH)

Vasopressin, also known as antidiuretic hormone (ADH), regulates water excretion by the kidneys. It is also a potent vasoconstrictor and can be used either directly or in synthetic form to achieve haemostasis, such as in severe gastrointestinal bleeding. ADH acts as an additional stimulus for ACTH release from corticotrophs during foetal development. When the body is dehydrated the extracellular fluid is detected by the osmoreceptors in the hypothalamus (supraoptic nucleus) to stimulate the release of ADH. This acts on the distal convoluted tubule and collecting duct of the kidneys via aquaporin 2 channels to increase the permeability of water, hence leading to water resorption and increased urine concentration. The osmoreceptors also stimulate the hypothalamic thirst centre.