Changes in the Conversion Rate of Tryptophan-nicotinamide According to Dietary Fat and Protein Levels

Shibata, Katsumi; Onodera, Michiko

doi:10.1271/bbb.56.1104

Cited by 16 publications

(14 citation statements)

References 9 publications

(9 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Weaning rats need 1 mg (8 mol) of niacin in 100 g of diet or 85 mg (420 mol) of tryptophan in 100 g of niacin-free diet for maximum growth (35,36). Since the 20% casein diet used in the present study contains 230 mg (1.1 mmol) of tryptophan in 100 g of diet, and young rats convert 2% of tryptophan into nicotinamide in molar basis (37), the 20% casein diet contains enough tryptophan to supply nicotinamide for maximum growth in rats. Therefore our findings in the rats fed with the niacin-free 20% casein diet are considered to be applied to rats fed with niacin-containing diet.…”

Section: Discussionmentioning

confidence: 99%

Age-Related Alterations of B-Group Vitamin Contents in Urine, Blood and Liver from Rats

Fukuwatari

Wada

Shibata

2008

J Nutr Sci Vitaminol

Self Cite

View full text Add to dashboard Cite

SummaryTo investigate how aging alters B-group vitamin metabolism, rats were fed with niacin-free 20% casein diet from 3 to 80 wk old, and the urinary excretions of the B group vitamins were periodically measured. The blood and liver B-group vitamin levels in 80-wk-old rats were also compared with those in 8-wk-old rats. The urinary excretion of thiamin, riboflavin, vitamin B 6 metabolite 4-pyridoxic acid, pantothenic acid, folic acid and biotin were not altered during 540 d. The urinary vitamin B 12 increased by 8-fold at 29 wk old, and further increased at 80 wk old. Conversion of nicotinamide from tryptophan gradually decreased to 60% from 29 to 48 wk old. Plasma PLP, vitamin B 12 and folate levels in 80-wk-old rats were lower than those in 8-wk-old rats, consistent with lower liver vitamin B 6 and folate levels in aged rats. Plasma and liver biotin levels in aged rats were higher than those in young rats. Other B-group vitamins such as vitamin B 1 , vitamin B 2 , niacin and pantothenic acid levels in blood and liver from aged rats were same as those from young rats. Alteration of vitamin B 6 metabolism in particular is similar to the observations in eldery humans reported previously. Our findings suggest that aged rats can be useful models to investigate aging-related B-group vitamin metabolism. Key Words aging, vitamin B 2 , vitamin B 6 , folate, biomarker The precise cascade of pathological age-related events is still not clearly understood, but enhanced production of free radicals and its deleterious effects on macro-biomolecules such as proteins and DNA ( 1 , 2 ) as well as polyunsaturated fatty acids ( 3 ) are well known during aging. Aging is a major risk factor for various chronic disorders including cancer. It is well known that taking in nutrients suitable for life stages is important to prevent the aging process and chronic disorders. Food, namely nutrient intake, is a key factor affecting aging and the incidence of many chronic disorders ( 4 -6 ). Decreased food intake and a sedentary lifestyle reduce energy expenditure and may alter their metabolism in elderly adults, and alteration of metabolism may cause alteration of nutrient requirement. However, there is not sufficient information on how aging alters vitamin metabolism ( 7 , 8 ). To investigate age-related alterations of B-group vitamins, rats were kept for 540 d from 3 to 80 wk old, and the urinary excretions of the B group vitamins were periodically measured. The blood and liver B-group vitamin levels in 80-wk-old rats were also compared with those in 8-wk-old rats.

show abstract

Section: Discussionmentioning

confidence: 99%

Age-Related Alterations of B-Group Vitamin Contents in Urine, Blood and Liver from Rats

Fukuwatari

Wada

Shibata

2008

J Nutr Sci Vitaminol

Self Cite

View full text Add to dashboard Cite

show abstract

“…1). Numerous factors such as pregnancy, 7) nutrition, [8][9][10][11][12][13][14][15] hormones, [16][17][18][19][20] chemicals, [21][22][23][24][25][26] and experimental models of diseases [27][28][29] affect this conversion from tryptophan to nicotinamide. However, little is known about the association between the nicotinamide intake and tryptophan-nicotinamide pathway.…”

mentioning

confidence: 99%

Effects of Excess Nicotinamide Administration on the Urinary Excretion of NicotinamideN-Oxide and Nicotinuric Acid by Rats

Fukuwatari

Wada

Sasaki

et al. 2004

Bioscience, Biotechnology, and Biochemistry

Self Cite

View full text Add to dashboard Cite

“…In this connection, AMS is metabolized into acetyl-CoA. The liver QPRT activity is reduced only by feeding of adenine resulting in renal failure, 45) and the liver ACMSD activity is aŠected by dietary protein levels, 6,46) the composition of fatty acids in fats, 6,46,47) diabetes, 5,48) and some hormones. 49) In this study, administration of orotic acid did not in‰uence the activities of QPRT or ACMSD.…”

Section: Discussionmentioning

confidence: 99%

“…Shibata et al 5) have been reported that the conversion ratio was lower in diabetic rats than in normal rats. Furthermore, Shibata and Onodera 6) have been reported that a large amount of fat administration, especially oil including with polyunsaturated fatty acids, signiˆcantly increased the conversion ratio. From these reports, it might be probable that the metabolism of tryptophan to niacin is disturbed in fatty liver.…”

mentioning

confidence: 99%

Effects of Fatty Liver Induced by Niacin-free Diet with Orotic Acid on the Metabolism of Tryptophan to Niacin in Rats

Fukuwatari

Morikawa

Sugimoto

et al. 2002

Bioscience, Biotechnology, and Biochemistry

Self Cite

View full text Add to dashboard Cite

Changes in the Conversion Rate of Tryptophan-nicotinamide According to Dietary Fat and Protein Levels

Cited by 16 publications

References 9 publications

Age-Related Alterations of B-Group Vitamin Contents in Urine, Blood and Liver from Rats

Age-Related Alterations of B-Group Vitamin Contents in Urine, Blood and Liver from Rats

Effects of Excess Nicotinamide Administration on the Urinary Excretion of NicotinamideN-Oxide and Nicotinuric Acid by Rats

Effects of Fatty Liver Induced by Niacin-free Diet with Orotic Acid on the Metabolism of Tryptophan to Niacin in Rats

Contact Info

Product

Resources

About