ADH levels during dehydration and over hydration?

Answer 1

ADH works to reabsorb water from the lumen of the collecting ducts in the kidneys back into the interstitial space. As a result, high levels of ADH will result in higher concentrations of aquaporin-2 on the luminal membrane, allowing for H2O reabsorption in the otherwise-H2O-impermeable collecting ducts. As a result, the urine will be more highly concentrated due to the loss of water (back into the blood), reaching an osmolarity of around 1400 mOsm maximum.

In dehydration, ADH levels are high (enables the body to retain more water) and in over-hydration, ADH levels are low (no need for the body to retain water, hence increased micturition)