FINASTERIDE INHIBITS 5-ALPHA-REDUCTASE ACTIVITY IN HUMAN DERMAL FIBROBLASTS - PREDICTION OF ITS THERAPEUTIC APPLICATION IN ANDROGEN-RELATEDSKIN DISEASES

Background. The potential role of finasteride in treating androgen rel ated skin disorders was investigated. Methods. Pooled human dermal fib roblasts were used to assess the effect of finasteride on the 5 alpha- reductase activity in skin tissue. V-max and K-m were estimated in the presence of 0, 10, and 200 nM finasteride. Results. V-max values rema in constant near 1.20 pmol/mg protein/h in the presence of increasing concentrations of finasteride; however, apparent K-m increases from 0. 27 nM at 0 nM finasteride to 0.31 nM and 0.44 nM at 10 nM and 200 nM f inasteride, respectively. This suggests that finasteride competes with testosterone and has a high affinity for same binding site of the 5 a lpha-reductase enzyme. Apparent K-i was estimated at 282 nM, indicatin g that a high concentration of finasteride is required to significantl y suppress the enzyme activity, Conclusions. This study confirms that finasteride inhibits the conversion of testosterone to dihydrotestoste rone in human reticular dermal fibroblasts. Finasteride may have thera peutic potential in treating skin disorders influenced by the action o f dihydrotestosterone.