2. ADH
• Antidiuretic hormone, also known commonly as arginine
vasopressin, is a nine amino acid peptide secreted from
the posterior pituitary. Within hypothalamic neurons, the
hormone is packaged in secretory vesicles with a carrier
protein called neurophysin, and both are released upon
hormone secretion
3. Physiologic Effects of Antidiuretic
• Hormone Effects on the Kidney The single most
important effect of antidiuretic hormone is to
conserve body water by reducing the loss of water
in urine. A diuretic is an agent that increases the
rate of urine formation. Injection of small amounts
of antidiuretic hormone into a person or animal
results in antidiuresis or decreased formation of
urine, and the hormone was named for this effect
4. • Antidiuretic hormone binds to receptors on cells in the
collecting ducts of the kidney and promotes reabsorption
of water back into the circulation. In the absense of
antidiuretic hormone, the collecting ducts are virtually
impermiable to water, and it flows out as urine.
• Antidiuretic hormone stimulates water reabsorbtion by
stimulating insertion of "water channels" or aquaporins
into the membranes of kidney tubules. These channels
transport solute-free water through tubular cells and back
into blood, leading to a decrease in plasma osmolarity
and an increase osmolarity of urine
5. • The more concentrated the plasma, the more ADH is
released into the blood. When the ADH reaches the
kidneys, it causes them to reabsorb more water. This
keeps more water in the body and produces more
concentrated urine .When the plasma is more dilute, less
ADH is released into the bloodstream. This allows more
water to leave the kidneys, producing more dilute
urine.This method of control is an example of negative
feedback
6.
7.
8. Effects on the Vascular System
• In many species, high concentrations of antidiuretic
hormone cause widespread constriction of arterioles,
which leads to increased arterial pressure. It was for this
effect that the name vasopressin was coined. In healthy
humans, antidiuretic hormone has minimal pressor effects
9. How alcohol and ecstasy affect ADH
• Alcohol suppresses ADH production. This causes the
kidneys to produce more dilute urine. It can lead to
dehydration. Ecstasy increases ADH production. This
causes the kidneys to reabsorb water. It can result in the
body having too much water
10. Disease
• States The most common disease of man and animals
related to antidiuretic hormone is diabetes insipidus. This
condition can arise from either of two situations:
• Hypothalamic ("central") diabetes insipidus results from a
deficiency in secretion of antidiuretic hormone from the
posterior pituitary. Causes of this disease include head
trauma, and infections or tumors involving the
hypothalamus.
• Nephrogenic diabetes insipidus occurs when the kidney is
unable to respond to antidiuretic hormone. Most
commonly, this results from some type of renal disease,
but mutations in the ADH receptor gene or in the gene
encoding aquaporin-2 have also been demonstrated in
affected humans
