In vitro effects of an aromatase inhibitor on 5 alpha-reductase activity in human hypertrophic prostatic tissue.
To determine the effects of 4-hydroxy-4-androstene-3,17-dione (4-OH-A) on the in vitro conversion of testosterone (T) to 5 alpha-androstan-17 beta-ol-3-one (dihydrotestosterone, DHT), 5 alpha-androstan-3 alpha, 17 beta-diol and 5 alpha-androstan-3 beta, 17 beta-diol (diols), human benign hypertrophic prostatic (BPH) tissue was incubated with 4-14C-T as substrate, in the presence of 4-OH-A (10(-8) to 10(-6) M); the amounts of the 5 alpha-reduced metabolites formed were quantitated. The effects of 4-OH-A were compared with those of 17 beta-N,N-diethylcarbamoyl-4-methyl-4-aza-5 alpha-androstan-3-one (4-MA), a known inhibitor of the 5 alpha-reductase. In the absence of 4-OH-A and 4-MA, human BPH tissue converted T to DHT and the diols readily. Both 4-OH-A and 4-MA induced significant and dose-related decreases in the formation of both DHT and the diols. The degree of inhibition induced by the different concentrations of 4-OH-A and 4-MA were 31, 41, 72% and 57, 87, 97%, respectively. The decreased formation of the diols was a consequence of the decreased availability of DHT (the immediate precursor of the diols) and was not due to direct effects of the inhibitors on the 3-hydroxysteroid dehydrogenases; both 4-OH-A and 4-MA were totally unable to modify the conversion of DHT to the diols, when 4-14C-DHT was used as substrate. Thus, 4-OH-A inhibits the process of 5 alpha-reduction of T in BPH tissue. This molecule might represent a potential new agent for the prevention and/or treatment of human BPH.
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S
Zoppi
M
M
Cocconi
A
A
Natali
A
A
Costantini
M
M
Serio
L
L
Martini
M
M
Motta
D058891:5-alpha Reductase Inhibitors; D000368:Aged; D015113:Androstane-3,17-diol / Q000096:biosynthesis; D000735:Androstenedione / Q000031:analogs & derivatives* / Q000494:pharmacology; D047072:Aromatase Inhibitors; D001378:Azasteroids / Q000494:pharmacology; D013196:Dihydrotestosterone / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D011470:Prostatic Hyperplasia / Q000201:enzymology*; D013739:Testosterone / Q000378:metabolism
D058891:5-alpha Reductase Inhibitors; D047072:Aromatase Inhibitors; D001378:Azasteroids; D013196:Dihydrotestosterone; D015113:Androstane-3,17-diol; D013739:Testosterone; D000735:Androstenedione; C031563:17-N,N-diethylcarbamoyl-4-methyl-4-azaandrostane-3-one; C014594:formestane