Microanalysis of tryptophan metabolites and suppressor factor of delayed-type hypersensitivity in mice

Abstract

We developed methods for the fluorometric assay of 3-hydroxykynurenine and 3-hydroxy-anthranilic acid, which are suspected as carcinogens in bladder cancer. It was shown that the urinary excretion of 3-hydroxyanthranilic acid increased in patients with bladder cancer. We also developed methods for the fluorometric assay of glucuronide and sulfate of 3-hydroxyanthranilic acid and showed that the excretion of these conjugated forms was minor in humans. The distribution of 3-hydroxykynurenine was studied and data obtained suggested that it has an affinity for the pancreas. We then developed methods for determination of the related compounds of tryptophan. Fluorescence reaction with UV radiation was applied to the determinations of kynurenic acid, kynurenine, quinolinic acid, nicotinic acid, nicotinamide, N1-methyl-nicotinamide, isatin, xanthrenic acid, and melatonin in the serum or urine. Furthermore, the fluorescence reaction with UV radiation was applied to some drugs, e.g., indomethacin, isoniazid, naldixic acid, nicorandil, and disodium cromoglycate. The relationship was investigated between the tumor promoter, 12-tetradecanoyl-phobol-13-acetate (TPA), and delayed hypersensitivity in mice. The foot pad reaction (FPR) in mice was suppressed by the application of TPA following the application of 7,12-dimethylbenz[alpha]-anthracene (DMBA), a tumor initiator, in BALB/c mice, while the FPR was suppressed by the application of TPA alone in C3H/He mice. CD8+ and CD4+ T cells, which suppress the FPR, were induced in BALB/c and C3H/He mice, respectively. These T cells produced soluble factors that inhibited the FPR in mice.