Abstract
5α-Dihydrotestosterone (DHT) is the primary active metabolite of testosterone, catalyzed by 5α-reductase (5αR) in the skin, prostate, and liver. In this study, the 5αR activity in rat liver S9 fraction in the presence of a NADPH-generating system was evaluated and compared by gas chromatography-mass spectrometry (GC-MS)-based in vitro assays. Testosterone and a 5αR inhibitor, finasteride, were added to the S9 fractions and incubated at 37oC for 1 h. Both testosterone and DHT were quantitatively measured and compared with two different GC-MS-based steroid profiling techniques. DHT was not detected by conventional GC-MS analysis in the absence of finasteride when the concentration of testosterone in the S9 fraction was less than 0.2 μM, whereas the isotope-dilution GC-MS (GC-IDMS) system was able to evaluate the 5αR activity. Because the S9 fraction contains more reactive enzymes and is easier to collect from tissues compared with a microsomal solution, the combination of the S9 fraction and GC-IDMS technique may be a promising assay for evaluating the 5αR activity in large-scale clinical studies.
Original language | English |
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Pages (from-to) | 21-24 |
Number of pages | 4 |
Journal | Mass Spectrometry Letters |
Volume | 3 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2012 |
All Science Journal Classification (ASJC) codes
- Analytical Chemistry
- Biochemistry, Genetics and Molecular Biology(all)
- Spectroscopy