Increased conversion ratio of tryptophan to niacin by dietary di-n-butylphthalate.
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.
Shibata
K
K
Department of Life Studies, School of Human Cultures, The University of Shiga Prefecture, Hikone, Japan.
Fukuwatari
T
T
Enomoto
A
A
Sugimoto
E
E
D000818:Animals; D002364:Caseins / Q000008:administration & dosage; D003993:Dibutyl Phthalate / Q000008:administration & dosage* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D008297:Male; D009525:Niacin / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D014364:Tryptophan / Q000378:metabolism*
D002364:Caseins; D003993:Dibutyl Phthalate; D009525:Niacin; D014364:Tryptophan