| The influence of diet on isotope ratio mass spectrometry values. | |
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MedLine Citation:
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PMID: 19638822 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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OBJECTIVES: Athletes have increasingly used testosterone (T) and other endogenous anabolic steroids that cannot be detected by conventional gas chromatography-mass spectrometry. This led to gas chromatography-combustion-isotope ratio mass spectrometry(GC/C/IRMS), which measures the relative amount of 13C in urinary steroids. Because exogenous testosterone is relatively low in 13C content, this study will determine if consuming a diet low in 13C plants, such as soy, can be confused with a GC/C/IRMS-positive test for exogenous testosterone. DESIGN: Cross-sectional study in which 22 vegetarians known to consume a diet depleted of 13C isotope were compared with a geographic control group of 14 subjects consuming a normal diet. SETTING: Two distinct subject populations with respect to diet. SUBJECTS: Subjects were recruited from a soy-based cooperative and control volunteers. Twenty-two of 24 research subjects completed the protocol compared with 14 of 22 control subjects. INTERVENTIONS: Independent variables were delta13C IRMS values,urinary steroid profile, and isoflavone analysis. MAIN OUTCOME MEASURES: Comparisons were made with respect to dietary analysis, isoflavones, and urinary steroid measurements using GC-C-IRMS. RESULTS: The delta13C values for 2 major metabolites of T (androsterone and etiocholanolone) were lower for the vegetarians than the controls (P = 0.005). The vegetarians excreted a median of 23 micromol/d of total isoflavones compared with 2.7 micromol/d for the control group (P =0.0002). CONCLUSIONS: The carbon isotope ratios of urinary testosterone metabolites of vegetarians consuming a diet that is markedly depleted of 13C content were lower than that of control subjects, but not low enough to result in World Anti-Doping Agency criteria for a positive IRMS analysis. |
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Authors:
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Gary Green; Rodrigo Aguilera; Brian Ahrens; Boro Starcevic; Felice Kurtzman; Jinbo Su; Don Catlin |
Publication Detail:
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Type: Comparative Study; Journal Article |
Journal Detail:
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Title: Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine Volume: 19 ISSN: 1536-3724 ISO Abbreviation: Clin J Sport Med Publication Date: 2009 Jul |
Date Detail:
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Created Date: 2009-07-29 Completed Date: 2009-11-17 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9103300 Medline TA: Clin J Sport Med Country: United States |
Other Details:
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Languages: eng Pagination: 287-92 Citation Subset: IM |
Affiliation:
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Department of Pathology, UCLA Olympic Analytical Laboratory, 2122 Granville Avenue, Los Angeles, CA 90025, USA. ggreen@mednet.ucla.edu |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adolescent Adult Anabolic Agents / urine Carbon Isotopes / analysis* Cross-Sectional Studies Diet* Doping in Sports Female Gas Chromatography-Mass Spectrometry / standards* Humans Male Middle Aged Reference Values Soy Foods Substance Abuse Detection Young Adult |
| Chemical | |
Reg. No./Substance:
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0/Anabolic Agents; 0/Carbon Isotopes |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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