title: NMR and pattern recognition studies on liver extracts and intact livers from rats treated with alpha-naphthylisothiocyanate.
abstract: The metabolite profiles from livers of toxin-treated rats were investigated using high resolution 1H NMR spectroscopy of aqueous (acetonitrile/water), lipidic (chloroform/methanol) extracts and magic angle spinning (MAS)-NMR spectroscopy of intact tissue. Rats were treated with the model cholestatic hepatotoxin, alpha-naphthylisothiocyanate (ANIT, 150 mg/kg) and NMR spectra of liver were analysed using principal components analysis (PCA) to extract novel toxicity biomarker information. 1H NMR spectra of control aqueous extracts showed signals from a range of organic acids and bases, amino acids, sugars, and glycogen. Chloroform/methanol extracts showed signals from a range of saturated and unsaturated triglycerides, phospholipids and cholesterol. The MAS 1H NMR spectra of livers showed a composite of signals found in both aqueous and lipophilic extracts. Following ANIT treatment, 1H NMR-PCA of aqueous extracts indicated a progressive reduction in glucose and glycogen, together with increases in bile acid, choline, and phosphocholine signals. 1H NMR-PCA of chloroform/methanol extracts showed elevated triglyceride levels. The 1H MAS-NMR-PCA analysis allowed direct detection of all of the ANIT-induced tissue perturbations revealed by 1H NMR of extracts, enabling metabolic characterisation of the lesion, which included steatosis, bile duct obstruction and altered glucose/glycogen metabolism. MAS-NMR spectroscopy requires minimal sample preparation and, unlike 1H NMR spectroscopy of tissue extracts, does not discriminate metabolites based on their solubility in a particular solvent and so this is a particularly useful exploratory tool in biochemical toxicology.
authors.affiliation: Division of Biomedical Sciences, Biological Chemistry, Sir Alexander Fleming Building, Imperial College, London, UK.
authors.forename: Nigel J
authors.initials: NJ
authors.lastname: Waters
authors.forename: Elaine
authors.initials: E
authors.lastname: Holmes
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Waterfield
authors.forename: R Duncan
authors.initials: RD
authors.lastname: Farrant
authors.forename: Jeremy K
authors.initials: JK
authors.lastname: Nicholson
mesh_terms: D015058:1-Naphthylisothiocyanate / Q000633:toxicity*; D000818:Animals; D008099:Liver / Q000737:chemistry / Q000187:drug effects*; D008110:Liver Extracts / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D013058:Mass Spectrometry; D010363:Pattern Recognition, Automated; D051381:Rats; D017208:Rats, Wistar
chemical_list: D008110:Liver Extracts; D015058:1-Naphthylisothiocyanate