FinasterideFinasteride
FunctionFunction
StructureStructure
Finasteride is an azasteroid, which is a synthetic compound derived from steroids. All steroids contain a core structure called a gonane, a structure composed of 3 cyclohexane rings and 1 cyclopentane ring "fused" together.
MechanismMechanism
==Finasteride is a 5-alpha reductase inhibitor. There are two isoforms of the 5alpha-reductase enzyme, type I and II, and while the drug has a higher affinity for the type II enzyme, it also inhibits the function of the type I. (.....) Typically 5 alpha-redcutase turns testosterone into Dihydrotestosterone(DHT), but the enzyme will accept Finasteride as an alternate substrate; turning it into dihydrofinasteride through an enzyme bound, NADP-dihydrofinasteride adduct. Finasteride is similar in structure to testosterone and 5alpha-reductase has almost the same affinity for both molecules. However, Finasteride , having a high affinity for 5 alpha-reductase, covalently binds to the enzyme as a Michael acceptor, through a functionally irreversible reaction. However, the NADP-dihydrofinasteride complex breaks down with a half life of about 1 month at 37˚C., which is why patients must continue taking the drug.(.....) Mechanism:
=Medical Uses=Medical Uses
Finasteride is used to shrink an enlarged prostate, also known as benign prostatic hyperplasia (BPH), in adult men. This medication works by inhibiting 5a-reductase, which prevents conversion of testosterone to the natural body hormone, dihydrosestosterone (DHT) that causes growth of the prostate. Finasteride is specific for type II isoenzymes, resulting in a decline in serum DHT levels by 65-70% and in prostate DHT levels by up to 80-90% (source).