This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Pharmacology
[{'content': 'Finasteride acts by blocking \nSelect and explain. \nA. Alpha receptor, B. 5 alpha reductase enzyme, C. 5 alpha reductase enzyme, D. Beta receptors', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Finasteride is a competitive inhibitor of the enzyme 5alpha-reductase which conves testosterone into more active DHT responsible for androgen action in many tissues. finasteride, dutasteride- used for prostate cancer and BPH (Ref.Essentials of medical pharmacology TD Tripathi 7th edition page no.302)', 'role': 'assistant'}]