Sandbox 45673: Difference between revisions
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==Mechanism== | ==Mechanism== | ||
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.<ref name="four"> Schieck, Cynthia L.(1998, August) "Finasteride (Propecia ®)". http://www.chm.bris.ac.uk/motm/finasteride/Finasteride%20(Propecia)%20-%20Feature%20Molecule.htm <ref | 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.<ref name="four"> Schieck, Cynthia L.(1998, August) "Finasteride (Propecia ®)". http://www.chm.bris.ac.uk/motm/finasteride/Finasteride%20(Propecia)%20-%20Feature%20Molecule.htm </ref> | ||
Typically 5α-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 5α-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.(Bull ''et. al,1995'') | Typically 5α-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 5α-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.(Bull ''et. al,1995'') | ||