• DOI:10.1248/CPB.32.2353
• Corpus ID: 27354833

Effect of combined administration of tryptophan with putative tryptophan pyrrolase inhibitors, DL-3-pyridylalanine, allopurinol or nicotinamide, on brain serotonin concentration.

@article{Shimeno1984EffectOC,
  title={Effect of combined administration of tryptophan with putative tryptophan pyrrolase inhibitors, DL-3-pyridylalanine, allopurinol or nicotinamide, on brain serotonin concentration.},
  author={Hiroshi Shimeno and Y Fukumoto and M Fuji and Atsuo Nagamatsu},
  journal={Chemical \& pharmaceutical bulletin},
  year={1984},
  volume={32 6},
  pages={
          2353-63
        }
}

• H. Shimeno, Y. Fukumoto, +1 author A. Nagamatsu
• Published 25 June 1984
• Biology, Chemistry
• Chemical & pharmaceutical bulletin

1) Single administration of tryptophan (25-200 mg / kg) to Wistar male rats resulted in a dose-related increase in liver tryptophan pyrrolase (TP) activity. The increase in brain serotonin (5-HT) concentration was not proportional to the dose given, and brain 5-HT concentration rapidly fell to the control (saline-treated) level or below. 2) The tryptophan-induced increase in liver TP activity was clearly prevented by DL-3-pyridylalanine (3-PA, 100 mg/kg). Serum free tryptophan and brain 5-HT concentrations increased more markedly and maintained higher levels after the combined administration of tryptophan with 3-PA than after a single administration of tryptophan. 3) Although allopurinol (20 mg/kg) reduced liver TP activity under control and tryptophan-treated conditions, it did not increase serum free tryptophan and brain 5-HT concentrations. 4) Nicotinamide also failed to alter the catabolism of tryptophan and the concentration of brain 5-HT in control or tryptophan-treated rats. 5) These data suggest that 3-PA would increase the therapeutic effect of tryptophan given to treat depressive illness, but that allopurinol and nicotinamide would not be suitable drugs for this purpose.