What is ADH in relation to the kidney?

Answer 1

ADH is a hormone secreted by the posterior lobe of the pituitary gland, in the brain. ADH travels in the blood to its target organ, the kidney, where it combines with complementary receptors on the surface of the plasma membranes of cuboidal epithelial cells making up the wall of the collecting ducts of nephron.

This stimulates a series of enzyme controlled reactions, resulting in production of an active phosphorylase enzyme which causes vesicles which have plasma membranes posessing a large number of water permeable channels, to move across the cell and fuse with the cell's plasma membrane.

As a result of these water permeable channels, the walls of the collecting duct are more permeable, and water can move out of the lumen of the collecting duct by osmosis down a water potential gradient (this gradient is created by active pumping of inorganic ions into the medulla by the loop of Henle) and is reabsorbed into the blood. As a result, the urine will be more concentrated and have less water, and the organism will consequently conserve more water.

If an organism is dehydrated or has done lots of exercise and has been sweating, the osmoreceptors in the hypothalamus detect the change in water potential, and ADH is secreted from the posterior lobe of the pituitary gland, so water is conserved as described above. If the organism has drank a lot of water, this is also detected and no ADH is produced - the hormone operates on a system of negative feedback.

Answer 2

Lack of ADH (antidiuretic hormone) would cause the kidneys to produce large amounts of dilute urine, and prevent the kidneys from properly regulating blood salt levels. ADH deficiency is also known as Diabetes insipidus, and causes strong feelings of thirst due to the need to replace lost water.

Answer 3

It will make the kidneys reabsorb more water.

Answer 4

ADH, or antidiuretic hormone, causes the kidney tubules to increase water reabsorption. It is a hormone released by the brain to help the body maintain homeostasis.

Answer 5

ADH is anti-diuretic hormone - which is responsible for increasing water reabsorption in the kidneys. This means that less urine is produced.