title: Messenger RNA levels and enzyme activities of 5 alpha-reductase types 1 and 2 in human benign prostatic hyperplasia (BPH) tissue.
abstract: BACKGROUND
  Benign prostatic hyperplasia (BPH) development requires testicular androgens and aging. The principle prostatic androgen is dihydrotestosterone (DHT). Testosterone is converted to DHT by the enzyme 5 alpha-reductase. Two distinct 5 alpha-reductase enzymes, types 1 and 2, have been identified. While some studies have suggested that type 2 isoenzyme predominates in the prostate, studies on the prostatic localization of the two isoenzymes are controversial. The purpose of this study was to determine the quantitative expressions of 5 alpha-reductase types 1 and 2 in BPH tissues.
  
  
  METHODS
  We examined the localizations of types 1 and 2 isoenzymes in BPH tissues using immunohistochemical staining and a real-time quantitative RT-PCR assay using the TaqMan system. We measured the enzyme activities of types 1 and 2 at pH values of 7.5 and 5.0, respectively.
  
  
  RESULTS
  Our immunohistochemical study showed that type 1 isoenzyme was expressed predominantly in epithelial cells, whereas type 2 isoenzyme was expressed in both stromal and epithelial cells. The real-time RT-PCR assay demonstrated that the copy numbers of type 1 isoenzyme mRNA were significantly higher than those of type 2 isoenzyme mRNA. There were significant associations between enzyme activity at pH 7.5 and type 1 isoenzyme mRNA expression, and between the activity at pH 5.0 and type 2 mRNA expressions.
  
  
  CONCLUSIONS
  We demonstrated that 5 alpha-reductase type 1 had a specific enzyme activity in the prostate, which supports the hypothesis that the type 1 isoenzyme may play a significant role in maintaining prostate enlargement along with the type 2 isoenzyme.
authors.affiliation: Division of Urology, Department of Organs Therapeutics, Faculty of Medicine, Kobe University Graduate School of Medicine, Kobe, Japan. toshiro@med.kobe-u.ac.jp
authors.forename: Toshiro
authors.initials: T
authors.lastname: Shirakawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Okada
authors.forename: Bishnu
authors.initials: B
authors.lastname: Acharya
authors.forename: Zhujun
authors.initials: Z
authors.lastname: Zhang
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Hinata
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Wada
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Uji
authors.forename: Sadao
authors.initials: S
authors.lastname: Kamidono
authors.forename: Akinobu
authors.initials: A
authors.lastname: Gotoh
mesh_terms: D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D008297:Male; D011470:Prostatic Hyperplasia / Q000201:enzymology / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D007527:Isoenzymes; D012333:RNA, Messenger; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase