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Messenger RNA levels and enzyme activities of 5 alpha‐reductase types 1 and 2 in human benign prostatic hyperplasia (BPH) tissue
Author(s) -
Shirakawa Toshiro,
Okada Hiroshi,
Acharya Bishnu,
Zhang Zhujun,
Hinata Nobuyuki,
Wada Yoshitaka,
Uji Tatsuya,
Kamidono Sadao,
Gotoh Akinobu
Publication year - 2003
Publication title -
the prostate
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.295
H-Index - 123
eISSN - 1097-0045
pISSN - 0270-4137
DOI - 10.1002/pros.10313
Subject(s) - dihydrotestosterone , isozyme , prostate , hyperplasia , immunohistochemistry , androgen , testosterone (patch) , reductase , messenger rna , endocrinology , enzyme , biology , medicine , microbiology and biotechnology , biochemistry , gene , cancer , hormone
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. © 2003 Wiley‐Liss, Inc.