1. Effects of excess intake of leucine and valine deficiency on tryptophan and niacin metabolites in humans.
- Author
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Nakagawa I, Oguri S, Sasaki A, Kajimoto M, and Sasaki M
- Subjects
- Adult, Amino Acids administration & dosage, Amino Acids blood, Dose-Response Relationship, Drug, Female, Humans, Hydroxyindoleacetic Acid metabolism, Male, Middle Aged, Niacinamide analogs & derivatives, Niacinamide metabolism, Nitrogen urine, Pyridones metabolism, Pyridoxine pharmacology, Quinolinic Acids metabolism, Valine blood, Leucine adverse effects, Nicotinic Acids metabolism, Tryptophan metabolism, Valine deficiency
- Abstract
Nineteen healthy humans (2 men and 17 women) served as experimental subjects in 4 experiments using diets having different levels of leucine and also a valine-deficient diet. The effect of an excess intake of leucine, with and without addition of vitamin B-6, and the effect of a deficiency of valine on urinary excretions of N1-methylnicotinamide, N1-methyl-2-pyridone-5-carboxamide, nicotinic acid, quinolinic acid, and 5-hydroxyindole acetic acid, and on the level of plasma amino acids were investigated. There was no effect of leucine on the excretion of these metabolites, but a marked decrease in the plasma (or serum) valine level was observed. The same decrease was seen when a valine-deficient diet was fed.
- Published
- 1975
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