Studies on neurosteroidsXXIII. Analysis of tetrahydrocorticosterone isomers in the brain of rats exposed to immobilization using LC–MS
| Autor: | Tatsuya Higashi, Ayako Honda, Kazutake Shimada, Hitoe Maekubo, Hiroyuki Yokoi |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Neuroactive steroid
medicine.medical_treatment Metabolite Clinical Biochemistry Atmospheric-pressure chemical ionization Biochemistry Mass Spectrometry Steroid Immobilization chemistry.chemical_compound Endocrinology Isomerism Liquid chromatography–mass spectrometry medicine Animals Rats Wistar Derivatization Molecular Biology Tetrahydrocorticosterone Brain Chemistry Pharmacology Detection limit Chromatography Organic Chemistry Rats chemistry Steroids Corticosterone Chromatography Liquid |
| Zdroj: | Steroids. 72:865-874 |
| ISSN: | 0039-128X |
| DOI: | 10.1016/j.steroids.2007.07.008 |
| Popis: | The identification and quantification of tetrahydrocorticosterone isomers (THBs; 3alpha,5alpha-, 3beta,5alpha-, 3alpha,5beta- and 3beta,5beta-THB) in rat brains using liquid chromatography (LC)-mass spectrometry (MS) are described. For the identification, the THBs were converted to the atmospheric pressure chemical ionization (APCI)-active derivatives, i.e., the dinitrobezoyl esters and 2-nitro-4-trifluoromethylphenyl hydrazones, and detected in the negative-ion mode. These derivatives showed 60- and 40-fold higher sensitivities, respectively, than intact steroids measured in the positive-APCI-MS. The derivatized THBs were satisfactorily separated from the others during the reversed-phase LC. The THBs were not detected at all in the brains of the unstressed rats. When the rats were exposed to the immobilization for 20 min, 3alpha,5alpha- and 3beta,5alpha-THB were detected as the major metabolites together with small amounts of 3alpha,5beta- and 3beta,5beta-THB in the male rat brain, while only 3alpha,5alpha-THB was detected in the female rats. Thus, the steroid variety found in the brains was different between the sexes. In the next step, 3alpha,5alpha-THB, a major metabolite found in the brains of the stressed rats, was quantified as its dinitrobezoyl ester. This method was accurate and reproducible, and the limit of quantitation was 1.0 ng/g tissue when a 50 mg tissue sample was used. There was also a sex difference in the brain 3alpha,5alpha-THB level; it was significantly higher in the female rats than in the male rats (P0.05), although the brain corticosterone level was not higher in the stressed female rats than in the male rats (no statistical difference). |
| Databáze: | OpenAIRE |
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