title: Directly coupled high-performance liquid chromatography and nuclear magnetic resonance spectroscopic with chemometric studies on metabolic variation in Sprague--Dawley rats.
abstract: We report here the first combined use of NMR-PR (pattern recognition) analysis and directly coupled HPLC--NMR analysis to identify metabolic subpopulations in normal laboratory animals and their discriminating endogenous urinary biomarkers. Urine samples obtained from control Sprague-Dawley rats (n = 68) were analyzed using (1)H NMR spectroscopy and principal components (PC) analysis to investigate physiological variability. Two distinct subpopulations of animals were classified based on metabolite excretion profiles. Analysis of the PC loadings established the spectral regions that were responsible for classification of the subpopulations and was used to direct the identification of biomarkers using a directly coupled HPLC--NMR analysis. One population had low urinary hippurate levels together with an increased concentration of 3-(3-hydroxyphenyl)propionic acid (3-HPPA)and 3-hydroxycinnamic acid (3-HCA). The other subpopulation excreted high levels of hippurate. Thus, we report the bimodal occurrence of hippuric acid and chlorogenic acid metabolites in a genetically homogeneous population of rats maintained under identical conditions, which may have significance in relation to the understanding of the consequences of biochemical variation in animals used for drug toxicity testing.
authors.affiliation: Biological Chemistry, Biomedical Sciences Division, Imperial College of Science, Technology and Medicine, University of London, Sir Alexander Fleming Building, South Kensington, London SW10 2AZ, United Kingdom.
authors.forename: C L
authors.initials: CL
authors.lastname: Gavaghan
authors.forename: J K
authors.initials: JK
authors.lastname: Nicholson
authors.forename: S C
authors.initials: SC
authors.lastname: Connor
authors.forename: I D
authors.initials: ID
authors.lastname: Wilson
authors.forename: B
authors.initials: B
authors.lastname: Wright
authors.forename: E
authors.initials: E
authors.lastname: Holmes
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003373:Coumaric Acids / Q000737:chemistry / Q000378:metabolism / Q000652:urine; D006626:Hippurates / Q000737:chemistry / Q000378:metabolism / Q000652:urine*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D010363:Pattern Recognition, Automated; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D003373:Coumaric Acids; D006626:Hippurates; C038547:dihydro-3-coumaric acid; C030514:hippuric acid