ADH control of water excretion

ADH is important in control of water excretion. Explain:
a. What triggers ADH release?
b. Where is ADH released from?
c. How does ADH act on the kidney in increase water re-absorbption? (include a discussion of how ADH works in the kidney, especially its role in regulating Aquaporin, and what part of the kidney ADH acts). 
d. How would you expect ADH release to be differently regulated in our experimental conditions (hypo-, iso-, and hyper-tonic)?