PM15 Biomarkers
Exhibit Hall
8:00 AM - Monday

(PM238) Use of Accelerator Mass Spectrometry as a tool for wildlife metabolism and biomarker studies, using Japanese quail as a model.

Faulkner, B1, Wilson, B 1, Vogel , J 2, Dueker, S3, 1 University of California, Davis, Davis, CA, USA2 Lawrence Livermore National Laboratory, Livermore, CA, USA3 Vitalea Sciences, Inc, Davis, CA, USA

ABSTRACT- Methods applied in conventional metabolism studies are relatively blunt tools. High doses of compound, often at pharmacological rather than physiological levels, are necessary to overcome sensitivity limitations, and recoveries are often low. Biomarker development studies, especially for fecal or urine-based endpoints, often focus on measuring the parent or circulating compound without considering whether metabolized forms might be the more representative endpoint. Accelerator Mass Spectrometry (AMS) is a relatively new technology in biological sciences, and recently the potential of this technology in metabolism and biomarker studies has been recognized. In this study we characterized the metabolism of testosterone in male Japanese quail (Coturnix japonicus) using conventional methods and AMS, in order to develop a metabolic fingerpint which can be used to evaluate the potential biomarkers for the study of endocrine function. Male Japanese quail (n=4) were injected IM with 25 DPM (0.00001 uCi) of [14C]testosterone for AMS analysis. Samples were collected over a 120-hour period for time course and mass balance analysis, Collected samples were solubilized and aliquots were taken and combusted so that [14C] could be measured directly. The remainder of each 0-2 hour post-dose sample was extracted, processed and separated with reversed-phase HPLC, with collected fractions measured for [14C] to assess the metabolic profile. AMS quantified 14C metabolites down to approximately 1 amol (10-18), which represents a > 5-orders of magnitude improvement in sensitivity over traditional radiometric detectors. HPLC/AMS is an excellent tool for determining the metabolic profile of endogenous compounds, using a fraction of the material needed in conventional studies.

Key words: Japanese quail , biomarker development , steroid metabolism, testosterone

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