This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
[{'content': 'All of the following use c-AMP as a second messenger except: \nSelect and explain. \nA. Corticotropin, B. Dopamine, C. Glucagon, D. Vasopressin', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Vasopressin\xa0receptor\xa0 V1\xa0and\xa0V3 acts\xa0via IP3/calcium pathway. V2 acts via cAMP.', 'role': 'assistant'}]