Now, as a result of that, water will basically follow because if we have more sodium ions flowing out, the concentration here will increase, and so water will follow as a result. And that's exactly what aldo steroid does. So as sodium moves out of the lumen and into the interstituum, the surrounding tissue around the collecting dug, it also brings water along for the ride. 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.