Gas Chromatography-Mass Spectrometry Measurement of 6β-OH-Cortisol/Cortisol Ratio in Human Urine: A Specific Marker of Enzymatic Induction
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Francesca Luceri
Abstract
The urinary 6β-OH-cortisol/cortisol ratio is a specific, non-invasive marker for evaluating inductive or inhibitory effects on cytochrome P450 3A activity. We propose a new quantitative gas chromatographymass spectrometry with isotope dilution (GC-ID-MS) method for the simultaneous determination of urinary free cortisol (UFC) and 6β-OH-cortisol (6β-OHC). The method utilizes the following: (a) addition of internal standard (2H2 cortisol) to 1 ml of urine; (b) loading on to an Extrelut column and elution with dichloromethane; (c) derivatization to dimethoxime tri-(trimethyl-silyl)-ether (MOX-TMS); (d) separation and identification by GC-ID-MS. The detection limit for cortisol was 22 pg injected (signal-to-noise ratio 10:1) and for 6β-OH-cortisol 123 pg injected (signal-to-noise ratio 10:1). The intra-assay and the inter-assay imprecision were 4.69% and 7.4% for 6β-OHC and 2.44% and 3.53% for cortisol, respectively. We used this method to analyze 57 morning urine samples of healthy volunteers and patients under different conditions. We found that chronic alcoholics had a significantly higher ratio of 6β-OHC/UFC compared to controls (p<0.0001), whereas adults undergoing methadone therapy and patients with acute alcohol intoxication exhibited a significantly lower urinary 6β-OHC/UFC ratio (p<0.05 and p<0.01, respectively). The proposed method allows a rapid and accurate assessment of the 6β-OHC/UFC ratio.
Copyright © 2001 by Walter de Gruyter GmbH & Co. KG
Articles in the same Issue
- Contents
- Subject Index
- Author Index
- Summary of the 2nd Sino-European Congress of Laboratory Medicine
- Laboratory Diagnosis of Viral Hepatitis in China: The Present and the Future
- Molecular Diagnostics in China
- Detection of Usual and Atypical Aldehyde Dehydrogenase Alleles by Mismatch Amplification Mutation Assay
- Expression of Prostaglandin D Synthase in Ovarian Cancer
- Carrier Detection and Prenatal Diagnosis of Hemophilia A
- Detection of Oligoclonal Immunoglobulins in the Cerebrospinal Fluid by Immunofixation Electrophoresis
- 2nd Sino-European Congress of Laboratory Medicine – Strategies for Laboratory Diagnostics in Medicine
- The Problems and Strategy relevant to the Quality Management of Clinical Laboratories
- Computer Application to the Laboratory Management in Hospital
- The Basis of the Synovial Fluid Analysis
- Determination of Tumor Markers in Serum. Pitfalls and Good Practice
- Gas Chromatography-Mass Spectrometry Measurement of 6β-OH-Cortisol/Cortisol Ratio in Human Urine: A Specific Marker of Enzymatic Induction
- No Variation in Hsp70 mRNA Level during Cardiac Surgery in Pediatric Patients Evaluated by Semiquantitative RT-PCR
- Rapid Detection of Macroprolactin in tHe Form of Prolactin-Immunoglobulin G Complexes by Immunoprecipitation with Anti-human IgG-Agarose
- Molecular Characterization of Chromosome 22 Deletions by Short Tandem Repeat Polymorphism (STRP) in Patients with Conotruncal Heart Defects
- A Simple and Rapid Analysis of Triplet Repeat Diseases by Expand Long PCR
- The Effects of Peroxynitrite on Erythrocytes
- The Use of Hirudin as Universal Anticoagulant in Haematology, Clinical Chemistry and Blood Grouping
- Comparison of Different Immunoassays for CA 19-9
- The Evaluation of Analytical Performance of the Precision G Point-of-Care Glucometer
- On Painting and Philosophy: Sir Henry Raeburn
- Acknowledgement
- Meetings and Awards
Articles in the same Issue
- Contents
- Subject Index
- Author Index
- Summary of the 2nd Sino-European Congress of Laboratory Medicine
- Laboratory Diagnosis of Viral Hepatitis in China: The Present and the Future
- Molecular Diagnostics in China
- Detection of Usual and Atypical Aldehyde Dehydrogenase Alleles by Mismatch Amplification Mutation Assay
- Expression of Prostaglandin D Synthase in Ovarian Cancer
- Carrier Detection and Prenatal Diagnosis of Hemophilia A
- Detection of Oligoclonal Immunoglobulins in the Cerebrospinal Fluid by Immunofixation Electrophoresis
- 2nd Sino-European Congress of Laboratory Medicine – Strategies for Laboratory Diagnostics in Medicine
- The Problems and Strategy relevant to the Quality Management of Clinical Laboratories
- Computer Application to the Laboratory Management in Hospital
- The Basis of the Synovial Fluid Analysis
- Determination of Tumor Markers in Serum. Pitfalls and Good Practice
- Gas Chromatography-Mass Spectrometry Measurement of 6β-OH-Cortisol/Cortisol Ratio in Human Urine: A Specific Marker of Enzymatic Induction
- No Variation in Hsp70 mRNA Level during Cardiac Surgery in Pediatric Patients Evaluated by Semiquantitative RT-PCR
- Rapid Detection of Macroprolactin in tHe Form of Prolactin-Immunoglobulin G Complexes by Immunoprecipitation with Anti-human IgG-Agarose
- Molecular Characterization of Chromosome 22 Deletions by Short Tandem Repeat Polymorphism (STRP) in Patients with Conotruncal Heart Defects
- A Simple and Rapid Analysis of Triplet Repeat Diseases by Expand Long PCR
- The Effects of Peroxynitrite on Erythrocytes
- The Use of Hirudin as Universal Anticoagulant in Haematology, Clinical Chemistry and Blood Grouping
- Comparison of Different Immunoassays for CA 19-9
- The Evaluation of Analytical Performance of the Precision G Point-of-Care Glucometer
- On Painting and Philosophy: Sir Henry Raeburn
- Acknowledgement
- Meetings and Awards
