Identification and measurement of kynurenic acid in the rat brain and other organs.
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.
Carlá
V
V
Department of Preclinical and Clinical Pharmacology, University of Florence, Italy.
Lombardi
G
G
Beni
M
M
Russi
P
P
Moneti
G
G
Moroni
F
F
D000818:Animals; D001923:Brain Chemistry; D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D007668:Kidney / Q000032:analysis; D007736:Kynurenic Acid / Q000032:analysis*; D008099:Liver / Q000032:analysis; D008297:Male; D009206:Myocardium / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains
D007736:Kynurenic Acid