Pharmacological and molecular evidence for the expression of the two steroid 5 alpha-reductase isozymes in normal and hyperplastic human prostatic cells in culture.
BACKGROUND
Whereas the embryological development of the human prostate is clearly dependent on steroid 5 alpha-reductase (5 alpha-R) type 2 expression, the respective expression of the two known isoforms (types 1 and 2) of 5 alpha-R in the adult human prostate remains unclear.


METHODS
5 alpha-R isoform mRNA expression (Northern blots and reverse transcriptase-polymerase chain reaction [RT-PCR]) and enzyme activity were studied in immortalized epithelial cells (NE) and in fibroblasts from normal (NF) or hyperplastic (BPHF) human prostates.


RESULTS
5 alpha-R activity (fmol/microgram DNA/hr) was 1.43 +/- 0.5 in NE, 10.7 +/- 4.7 in NF, and 79 +/- 37 in BPHF. mRNAs for both 5 alpha-R isoforms were expressed in the three cell types, as shown by Northern blot and RT-PCR analysis. LY306089, a selective 5 alpha-R type 1 inhibitor, strongly inhibited 5 alpha-R activity in all cell types (IC50: 10 nM), confirming the predominant expression of 5 alpha-R type 1 in these cells. Finasteride, a 5 alpha-R type 2 inhibitor, was less efficient (IC50: 45, 35, and 65 nM in NE, NF, and BPHF, respectively). In addition, the inhibition by finasteride decreased with serial subculture in NF only, suggesting an effect of age in culture on the expression of 5 alpha-R type 2 in these cells. SKF105657, also a 5 alpha-R type 2 inhibitor, was a poor inhibitor in this system.


CONCLUSIONS
These studies demonstrate that human prostate cells in culture express both isoforms of 5 alpha-R and suggest a balance in the expression of the two isoforms as a function of various regulatory factors.
Berthaut
I
I
Laboratoire de Biochimie B, Hôpital Necker-Enfants Malades, Paris, France.
Mestayer
C
C
Portois
M C
MC
Cussenot
O
O
Mowszowicz
I
I
D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000032:analysis* / Q000235:genetics; D058891:5-alpha Reductase Inhibitors; D000730:Androstadienes / Q000494:pharmacology; D001483:Base Sequence; D016227:Benzoquinones / Q000494:pharmacology; D015152:Blotting, Northern; D002460:Cell Line; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells; D004848:Epithelium / Q000201:enzymology / Q000473:pathology; D005347:Fibroblasts / Q000166:cytology / Q000201:enzymology / Q000473:pathology; D018120:Finasteride / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007527:Isoenzymes / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000235:genetics; D008297:Male; D009841:Oligonucleotides / Q000032:analysis / Q000737:chemistry / Q000235:genetics; D016133:Polymerase Chain Reaction; D011467:Prostate / Q000166:cytology / Q000201:enzymology* / Q000473:pathology; D011470:Prostatic Hyperplasia / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D012333:RNA, Messenger / Q000032:analysis / Q000737:chemistry / Q000235:genetics
D058891:5-alpha Reductase Inhibitors; D000730:Androstadienes; D016227:Benzoquinones; D004791:Enzyme Inhibitors; D007527:Isoenzymes; C101585:LY 306089; D009841:Oligonucleotides; D012333:RNA, Messenger; C072547:epristeride; D018120:Finasteride; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase