Now, earlier we said that ADH antidiaretic hormone basically produces more of these aquaporean channels. The question is, how exactly does this actually take place? So let's take a look at diagram A. In the absence of the ADH hormone, water is impermeable. So basically, water, these cells are impermeable to water. So if water tries to basically pass from the apical side to the bacillateral side, it will not be able to pass across.