Q.The vasopressin is otherwise called as :

Antidiuretic Hormone (ADH)

Your body must hold on to water carefully — lose too much and you dehydrate. The hormone that manages this at the level of the kidney is antidiuretic hormone (ADH), also called vasopressin. Its very name gives away its job: anti-diuretic means "against urine production", so ADH is the hormone that reduces water loss in urine.

Where it comes from

ADH is a peptide hormone made in the hypothalamus and released from the posterior pituitary gland (the neurohypophysis) into the blood. (A useful point: the posterior pituitary stores and releases ADH and oxytocin, which are actually produced by the hypothalamus.)

What it does — water reabsorption

When the body is short of water (dehydration, low blood volume), more ADH is released. It travels to the kidneys and acts on the distal tubules and collecting ducts of the nephrons, making their walls more permeable to water. As a result:

• More water is reabsorbed back into the blood.
• Less water is lost, so the urine becomes more concentrated and smaller in volume.

This conserves body water and helps keep blood pressure and fluid balance steady. (ADH also causes blood vessels to constrict — the "vasopressin" effect — which raises blood pressure.)

The feedback loop

ADH release is controlled by the body's water status. When you drink plenty of water, ADH falls, the kidney reabsorbs less water, and you produce large amounts of dilute urine. When you are dehydrated, ADH rises and you produce little, concentrated urine. It is a neat negative-feedback system.

The deficiency disorder — diabetes insipidus …