Finasteride acts by blocking: (A) Alpha receptor, (B) 5 alpha reductase enzyme, (C) 5 alpha reductase enzyme, (D) Beta receptors
Answer is B. 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)