HPLC method for the assessment of tryptophan metabolism utilizing separate internal standard for each detector.The development of a validated method, applicable for the measurement of tryptophan (TRP) and serotonin (5-HT), and that of the neuroprotective branch of the kynurenine pathway from several different biological matrices, including mouse brain, is described.  Following the spectral analysis of the metabolites, they were quantified with reversed-phase high-performance liquid chromatography (HPLC), using separate internal standards (ISs) for UV (3-nitro-L-tyrosine) and fluorescent (the newly utilized 4-hydroxyquinazoline-2-carboxylic acid) detectors.  The currently developed methods yield opportunities for the assessment of concentration changes in the TRP metabolism from a wide range of biological matrices, therefore they may well be utilized in future clinical and preclinical studies, especially in view that so many metabolites with the application of ISs have not been detected from mouse brain with such a simple HPLC method before.
HPLC