So let's discuss how each one of these hormones affects the functionality of our collecting duct. And let's begin with ADH. So, ADH, or antiduretic hormone, essentially stimulates the epithelial cells found along our collecting dust to produce membrane protein channels known as aquaporeans. And aquaporeans are these specialized types of channels found on the apical side of our membrane that are responsible for actually allowing the movement of water across the membrane. Now, the question is, in what direction will the water actually flow? Will the water flow out of the filtered and into the interstituum, or from the interstituum and back into our lumen of the collecting dug?