Direct determination of the ratio of tetrahydrocortisol + allo-tetrahydrocortisol to tetrahydrocortisone in urine by LC-MS-MS (Articolo in rivista)

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Label
  • Direct determination of the ratio of tetrahydrocortisol + allo-tetrahydrocortisol to tetrahydrocortisone in urine by LC-MS-MS (Articolo in rivista) (literal)
Anno
  • 2006-01-01T00:00:00+01:00 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi
  • 10.1016/j.jchromb.2005.11.011 (literal)
Alternative label
  • Raffaelli A., Saba A., Vignali E., Marcocci C., Salvadori P. (2006)
    Direct determination of the ratio of tetrahydrocortisol + allo-tetrahydrocortisol to tetrahydrocortisone in urine by LC-MS-MS
    in Journal of chromatography. B (Print)
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Raffaelli A., Saba A., Vignali E., Marcocci C., Salvadori P. (literal)
Pagina inizio
  • 278 (literal)
Pagina fine
  • 285 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
  • 830 (literal)
Rivista
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#pagineTotali
  • 8 (literal)
Note
  • ISI Web of Science (WOS) (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • CNR-ICCOM Sezione di Pisa; Dipartimento di Endocrinologia e Metabolismo, Ortopedia e Traumatologia, Medicina del Lavoro, Universita' di Pisa; Dipartimento di Chimica e Chimica Industriale, Universita' di Pisa; AmbiSEN-Environmental and Endocrine and Nervous System High Technology Centre for the Study of the Effects of Harmful Agents, Universita' di Pisa (literal)
Titolo
  • Direct determination of the ratio of tetrahydrocortisol + allo-tetrahydrocortisol to tetrahydrocortisone in urine by LC-MS-MS (literal)
Abstract
  • The 11beta-hydroxysteroid dehydrogenase (11beta-HSD) is responsible for the interconversion of both the hormonally inactive cortisone and the active cortisol. This enzyme activity, which has implications in the pathogenesis of numerous diseases, is reflected in the ratio of tetrahydrometabolites of cortisol (allo-tetrahydrocortisol and tetrahydrocortisol) to those of cortisone (tetrahydrocortisone). Several methods have been proposed in the literature to determine such a ratio in urine. Most of them require tedious and extensive extraction and derivatization steps and make use of gas-chromatographic techniques, including gas chromatography coupled to mass spectrometry (GC-MS). We present here an alternative approach for the direct determination of such a ratio in urine by using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS-MS), based on a minimal sample treatment. Actually, the limit of detections (LODs) for pure standards in water permitted a simple dilution of the urine samples prior to the analysis, hence, an accurate optimization of the high performance liquid chromatography (HPLC) separation was needed in order to get rid of the severe influence of the urine matrix on the ionization efficiency. Besides, the nature of some interfering species was deeply investigated, as well as the suitability of some commercial deuterated steroids as internal standards. All these led to the final method, which was based on a HPLC separation on a C8 column and a ternary gradient water/methanol/acetonitrile. In parallel, an appropriate sample preparation was set up, which consisted of an enzymatic hydrolysis of the conjugated species and a followed 1:20 dilution. Preliminary measurements on real urine samples were performed as well. (literal)
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