US EPA

1310628 

Journal Article 

Increased conversion ratio of tryptophan to niacin by dietary di-n-butylphthalate 

Shibata, K; Fukuwatari, T; Enomoto, A; Sugimoto, E 

2001 

Yes 

Journal of Nutritional Science and Vitaminology
ISSN: 0301-4800 

J Nutr Sci Vitaminol (Tokyo). 

47 

3 

263-266 

English 

11575584 

10.3177/jnsv.47.263 

WOS:000170254200013 

https://www.proquest.com/scholarly-journals/increased-conversion-ratio-tryptophan-niacin/docview/71195588/se-2
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We reported that the growth promoting activity of di-n-butylphthalate (DBP) was observed when rats were fed with a niacin-free and tryptophan-limiting diet (Shibata et al.. 1982. J Nutr Sci Vitaminol 28, 173-177). The present experiment was performed to investigate whether this phenomenon is attributable to the increase in the conversion ratio of tryptophan to niacin. The weaning rats were fed with a 10% (low protein diet) or 20% protein (conventional protein diet) diet with or without adding 1% DBP. The conversion ratio of tryptophan to niacin was significantly higher in the DBP group than in the control group; for 10% casein diets, it increased two-fold and for 20% casein diet, about five-fold. From these results, the previous finding is possibly explained by DBP increasing the conversion ratio of tryptophan to niacin. 

tryptophan metabolism; niacin; di-n-butylphthalate