This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
User:Cody J Cubbage
From Proteopedia
Contents |
Finasteride
Function
Structure
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.
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. (.....) 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
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).
