Studies on neurosteroids XXIV. Determination of neuroactive androgens, androsterone and 5α-androstane-3α,17β-diol, in rat brain and serum using liquid chromatography–tandem mass spectrometry
✍ Scribed by Tatsuya Higashi; Hiroyuki Yokoi; Yukiko Nagura; Tadashi Nishio; Kazutake Shimada
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 247 KB
- Volume
- 22
- Category
- Article
- ISSN
- 0269-3879
- DOI
- 10.1002/bmc.1078
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✦ Synopsis
Abstract
The development and validation of liquid chromatography–electrospray ionization–tandem mass spectrometric (LC–ESI‐MS/MS) methods that enable the quantification of neuroactive androgens, androsterone (5__α__‐androstan‐3__α__‐ol‐17‐one, 3__α__,5__α__‐A) and 5__α__‐androstane‐3__α__,17__β__‐diol (3__α__,5__α__‐Adiol), in the rat brain and serum are presented. The androgens were extracted with methanol–acetic acid, purified using solid‐phase extraction cartridges, derivatized with an ESI‐active reagent, isonicotinoyl azide (INA), and then subjected to LC–ESI‐MS/MS. The quantifications were based on selected reaction monitoring mode using the characteristic transitions of the INA derivatives. The methods allowed the reproducible and accurate quantification of the brain and serum neuroactive androgens using a 100 mg or 100 µL sample; the intra‐ and inter‐assay relative standard deviations were below 3.6%, and the percentage accuracy values were 97.1–103.7% for both androgens. The animal study using the methods suggests that most of 3__α__,5__α__‐Adiol found in the brain is derived from the periphery, while 3__α__,5__α__‐A is not only transported from the periphery into the brain, but also synthesized in the brain by the oxidation of 3__α__,5__α__‐Adiol. The androgens in the rats intraperitoneally administered finasteride, a 5__α__‐reductatse inhibitor, were also measured; this treatment significantly reduced the brain 3__α__,5__α__‐A and 3__α__,5__α__‐Adiol levels and increased only the brain level of androstenedione, the precursor of 3__α__,5__α__‐A. Copyright © 2008 John Wiley & Sons, Ltd.