Hostname: page-component-8448b6f56d-cfpbc Total loading time: 0 Render date: 2024-04-23T08:21:55.311Z Has data issue: false hasContentIssue false
  • English
  • Français

Effects of a dietary excess of leucine on the metabolism of tryptophan in the rat: a mechanism for the pellagragenic action of leucine

Published online by Cambridge University Press:  09 March 2007

David A. Bender
David A. Bender
Affiliation:
Courtauld Institute of Biochemistry, The Middlesex Hospital Medical School, London W1P 7PN
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

1. In order to investigate the mechanism of the pellagragenic action of excess dietary leucine, rats were fed on diets providing a minimally-adequate amount of tryptophan, with no preformed niacin, with and without the addition of 15 g leucine/kg diet. This amount of leucine in the diet has been demonstrated previously to lead to depletion of blood and liver nicotinamide nucleotides. The metabolism of tryptophan was assessed by measurement of the production of 14CO2 after the administration of [methylene-14C]tryptophan to estimate the activity of kynureninase (L-kynurenine hydrolase, EC 3.7.1.3) and [benzene ring U-14C]tryptophan to estimate the activity of picolinate carboxylase (aminocarboxymuconate semialdehyde decarboxylase, EC 4.1.1.45).

2. A dietary excess of leucine led to inhibition of kynureninase and increased the activity of picolinate carboxylase. Both of these effects would result in a reduction in the rate of metabolism of acroleylaminofumarate (aminocarboxymuconate semialdehyde) to quinolinic acid and hence to nicotinamide nucleotides. These two effects provide an explanation for the pellagragenic effect of a dietary excess of leucine in animals that are wholly or partly reliant on endogenous synthesis from tryptophan to meet their requirements for nicotinamide nucleotides, and presumably also explain the pellagragenic effect of a dietary excess of leucine in man.

Type
Papers of direct relevance to Clinical and Human Nutrition
Information
British Journal of Nutrition , Volume 50 , Issue 1 , July 1983 , pp. 25 - 32
Copyright
Copyright © The Nutrition Society 1983

References

REFERENCES

Bender, D. A., Magboul, B. I. & Wynick, D. (1982). British Journal of Nutrition 48, 119–127.CrossRefGoogle Scholar
Ghafoorunissa, & Narasinga Rao, B. S. (1973). Biochemical Journal 134, 425–430.CrossRefGoogle Scholar
Gopalan, C. & Srikantia, S. G. (1960). Lancet i, 954–957.CrossRefGoogle Scholar
Ikeda, M., Tsuji, H., Nakamura, S., Ichiyama, A., Nishizuka, Y. & Hayaishi, O. (1965). Journal of Biological Chemistry 240, 1395–1401.CrossRefGoogle Scholar
Krishnaswamy, K. & Bapu Rao, S. (1978). British Journal of Nutrition 39, 61–64.CrossRefGoogle Scholar
Magboul, B. I. & Bender, D. A. (1982). Proceedings of the Nutrition Society 41, 50A.Google Scholar
Magboul, B. I. & Bender, D. A. (1983). British Journal of Nutrition 49, 321–329.CrossRefGoogle Scholar
Nishizuka, Y. & Hayaishi, O. (1963). Journal of Biological Chemistry 238, 3369–3377.CrossRefGoogle Scholar
Sanada, H. & Miyazaki, M. (1980). Journal of Nutritional Science and Vitaminology 26, 617–627.CrossRefGoogle Scholar
Sanada, H., Miyazaki, M. & Takahashi, T. (1980). Journal of Nutritional Science and Vitaminology 26, 449–459.CrossRefGoogle Scholar
Smith, S. A., Carr, F. P. A. & Pogson, C. I. (1980). Biochemical Journal 192, 673–686.CrossRefGoogle Scholar
Stewart, K. K. & Doherty, R. F. (1973). Proceedings of the National Academy of Sciences USA 70, 2850–2852.CrossRefGoogle Scholar