This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney, Subject name: Pharmacology
Aldosterone exes action on 
Select and explain. 
A. Proximal tubule, B. Early Distal tubules, C. Loop of Henle, D. Collecting duct
D: Collecting duct
Answer: D: Collecting duct 
Explanation: Aldosterone acts on the late DT and CD cells by combining with an intracellular mineralocoicoid receptor - induces the formation of' aldosterone-induced proteins' (AlPs) which promote Na+ reabsorption by a number of mechanisms and K+ secretion. Aldosterone (AL) penetrates the cell from the interstitial side and combines with the mineralocoicoid receptor (MR). The complex translocates to the nucleus-promotes gene mediated mRNA synthesis. The mRNA then directs the synthesis of aldosterone-induced proteins (Alps). The AlPs activates Na+ channel, translocate Na+ channels from cytosolic site to the luminal membrane and Na+K+ATPase of the basolateral membrane, increase ATP production by mitochondria. All these changes promote Na+ reabsorption-more K+vand H+ is secreted indirectly ( Essentials of Medical Pharmacology, K.D Tripathi,6tth edition, page 570 )