Identification and measurement of kynurenic acid in the rat brain and other organs

• Published in: Analytical biochemistry Vol. 169; no. 1; p. 89
• Main Authors: Carlá, V, Lombardi, G, Beni, M, Russi, P, Moneti, G, Moroni, F
• Format: Journal Article
• Language: English
• Published: United States 15-02-1988
• Subjects: Animals; Brain Chemistry; Chromatography, High Pressure Liquid; Gas Chromatography-Mass Spectrometry; Kidney - analysis; Kynurenic Acid - analysis; Liver - analysis; Male; Myocardium - analysis; Rats; Rats, Inbred Strains
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(88)90258-8

Kynurenic acid, a biologically active tryptophan metabolite, has been identified and measured in the rat brain and other organs using HPLC and GC/MS. Both the described methods required extraction of the compound in alkaline ethanol and initial purification on Dowex ion-exchange resins. The GC/MS approach used 3-hydroxy-2-naphthoic acid as an internal standard and a derivatization procedure with diazomethane and trifluoroacetic anhydride. The HPLC procedure was performed on a reverse-phase column using a spectrophotometric detector. Both the GC/MS and the HPLC methods had the lowest detection limit in the range of 10 pmol/injection, but the variability of the results was lower when HPLC was used. HPLC analysis showed the content of kynurenic acid to be 14 +/- 2 pmol/g wet wt in the brain, 75 +/- 7 in the heart, 87 +/- 8 in the liver, and 298 +/- 10 in the kidneys. Comparable but variable values were obtained with GC/MS.