1H nuclear magnetic resonance (NMR) metabolomic study of chronic organophosphate exposure in rats

Todd M. Alam, Muniasamy Neerathilingam, M. Kathleen Alam, David E. Volk, G. A.Shakeel Ansari, Swapna Sarkar, Bruce A. Luxon

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


1H NMR spectroscopy and chemometric analysis were used to characterize rat urine obtained after chronic exposure to either tributyl phosphate (TBP) or triphenyl phosphate (TPP). In this study, the daily dose exposure was 1.5 mg/kg body weight for TBP, or 2.0 mg/kg body weight for TPP, administered over a 15-week period. Orthogonal signal correction (OSC) -filtered partial least square discriminant analysis (OSC-PLSDA) was used to predict and classify exposure to these organophosphates. During the development of the model, the classification error was evaluated as a function of the number of latent variables. NMR spectral regions and corresponding metabolites important for determination of exposure type were identified using variable importance in projection (VIP) coefficients obtained from the OSC-PLSDA analysis. As expected, the model for classification of chronic (1.5-2.0 mg/kg body weight daily) TBP or TPP exposure was not as strong as the previously reported model developed for identifying acute (15-20 mg/kg body weight) exposure. The set of majorly impacted metabolites identified for chronic TBP or TPP exposure was slightly different than those metabolites previously identified for acute exposure. These metabolites were then mapped to different metabolite pathways and ranked, allowing the metabolic response to chronic organophosphate exposure to be addressed.

Original languageEnglish (US)
Pages (from-to)479-495
Number of pages17
Issue number3
StatePublished - Jul 24 2012
Externally publishedYes


  • Chemometrics
  • Metabolomics
  • NMR
  • Tributyl phosphate
  • Triphenyl phosphate

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Biochemistry
  • Molecular Biology


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