title: Effect of a 4-methyl-4-aza steroid on androgen metabolism by rat ventral prostate epithelial and stromal cell cultures: selective inhibition of 5 alpha-reductase activity.
abstract: The effect of a potent steroid metabolic inhibitor, 17 beta-N,N-diethylcarbamoyl-4-methyl-4-aza-5 alpha-androstan-3-one (DMAA), on androgen metabolism was investigated in primary monolayer cultures of rat ventral prostate epithelial and stromal cells. Using testosterone (T) as substrate, 5 alpha-reductase (5 alpha-R) activity in both cell types was inhibited by greater than 98% at an inhibitor concentration of 1000 nM. The concentrations required to produce a 50% inhibition (IC50) were 7.4 and 9.0 nM for epithelial and stromal cells, respectively. To examine the specificity of this compound, its effect on other steroid-metabolic enzymes was examined. DMAA at a concentration of 1,000 nM had no effect on 3 alpha-hydroxysteroid oxidase (3 alpha-HSORox), 3-ketosteroid reductase (3 alpha-HSORred), and 6/7-hydroxylase (6/7-HSH) activities in both cell types; 17 beta-hydroxysteroid oxidase (17 beta-HSORox) activity, located primarily in epithelial cells, also was not influenced by DMAA. In contrast, epithelial 3 beta-hydroxysteroid oxidase (3 beta-HSORox) and 3-ketosteroid reductase (3 beta-HSORred) activities were inhibited by 65% (P less than .001) and 58% (P greater than .05), respectively, albeit the latter result was not statistically significant. Stromal 3 beta-HSORox and 3 beta-HSORred activities were negligible; hence the effect of the inhibitor of these enzymes could not be assessed. In conclusion, DMAA is a relatively selective and potent inhibitor of 5 alpha-R activity in primary cultures of rat ventral prostate epithelial and stromal cells and should be a useful compound for antagonizing androgen-mediated actions in the prostate and other androgen target tissues.
authors.affiliation: Department of Biochemistry, Queen's University, Kingston, Ontario, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Orlowski
authors.forename: A F
authors.initials: AF
authors.lastname: Clark
mesh_terms: D058891:5-alpha Reductase Inhibitors; D000726:Androgen Antagonists / Q000494:pharmacology*; D000818:Animals; D001378:Azasteroids / Q000494:pharmacology*; D002478:Cells, Cultured; D013196:Dihydrotestosterone / Q000031:analogs & derivatives* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004848:Epithelium / Q000378:metabolism; D008297:Male; D011467:Prostate / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013260:Steroids, Heterocyclic / Q000494:pharmacology*
chemical_list: D058891:5-alpha Reductase Inhibitors; D000726:Androgen Antagonists; D001378:Azasteroids; D013260:Steroids, Heterocyclic; D013196:Dihydrotestosterone; C031563:17-N,N-diethylcarbamoyl-4-methyl-4-azaandrostane-3-one