<prompt> Finasteride acts by blockingAlpha receptor5 alpha reductase enzyme5 alpha reductase enzymeBeta receptors  <response>: 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 