17-BETA-HYDROXYSTEROID OXIDOREDUCTASE IN EPITHELIUM AND STROMA OF HUMAN PROSTATE

被引:13
作者
TUNN, S [1 ]
SCHULZE, H [1 ]
KRIEG, M [1 ]
机构
[1] UNIV HERNE,DEPT UROL,CLIN MARIENHOSP,W-4690 HERNE 1,GERMANY
关键词
D O I
10.1016/0960-0760(93)90213-G
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
It is conceivable that androstenedione contributes indirectly to 5alpha-dihydrotestosterone formation in human prostate by its intraprostatic conversion to testosterone. This reversible conversion is catalyzed by the enzyme 17beta-hydroxysteroid oxidoreductase (17beta-HSOR). At present, rather limited information on kinetic parameters like specific concentration (V(max)), affinity to steroid substrates (K(m)S) and to pyridine nucleotides (K(m)N) of 17beta-HSOR is available, Thus, we determined those aforementioned kinetic parameters in epithelium and stroma of normal human prostate (NPR) and benign prostatic hyperplasia (BPH). The main results were: (1) the mean K(m)S of 17beta-HSOR(red)/NADPH was significantly (P < 0.0001) lower than those of all other 17beta-HSORs. (2) In almost all cases the mean V(max) was higher in BPH than NPR. (3) In all cases, the mean V(max)/K(m)S ratios of 17beta-HSOR(red) were higher than those of 17beta-HSOR(ox). The highest ratio was found regarding 17beta-HSOR(red)/NADPH in BPH stroma. (4) In stroma, a significantly positive correlation of V(max)/K(m)S of 17beta-HSOR(red)/NADPH with age was found. (5) The lowest K(m)N was found regarding NADP+, followed by NADPH. It is concluded that in human prostate the balance of the reversible conversion of testosterone to androstenedione is shifted potentially towards testosterone, particularly in BPH stroma.
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页码:91 / 101
页数:11
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