Vasopressin antagonist acts on: (A) Proximal convoluted tubule, (B) Distal convoluted tubule, (C) Coical collecting tubule, (D) Medullary collecting duct
Answer is D. Vaspression receptors(V2) are present on principal cells of inner medullary collecting tubule. The antagonist like Conivaptan and Tolvaptan may be used in conditions like SIADH and CHF.