Inappropriate diuretic hormone and diabetes incipidus both are
the disorders of of water regulation which affect the activity of
anti diuretic harmone
- Posterior pituitary produces hormone called arginine
vasopressin also called AVP
- AVP acts on renal tubules to induce water retention, which
leads to concentrated urine but in Diabetes incipidus there will be
defect in secretion and synthesis of vasopressin which leads to
decreased free water reabsorbtion in renal collecting tubules
- The pituitary gland is stimulated to secrete ADH when the body
senses hypertonisisty allowing absorption of water back in to
circulation
- This occurs by means of increased water permeability and sodium
absorption in the renal system, which prevents diuresis.
- When diuresis occurs, urine becomes concentrated and urine
output decreases
- Alternatively when the body senses hypotonisisty, ADH secretion
is suppressed and it leads to less concentrated and higher volume
of urine output