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Katsumi SHIBATA
Article type: Article
1990 Volume 64 Issue 1 Pages
1-18
Published: January 25, 1990
Released on J-STAGE: March 17, 2018
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Urinary excretion of N^1-methylnicotinamide (MNA) accounted for only a few per cent of nicotinamide and its catabolic metabolites, but, its pyridones [N^1-methyl-2-pyridone-5-carboxamide(2-Pyr) and N^1-methyl-4-pyridone-3-carboxamide (4-Pyr)] accounted for around 90% in rats fed an adequate amino acid diet. However, the proportion of the pyridones decreased and the proportion of MNA increased concomitantly, when rats were fed an inadequate amino acid diet. Therefore, urinary ratio of (2-Pyr+4-Pyr)/MNA increased greatly when rats fed an adequate amino acid diet were compared with those fed an inadequate amino and free-tryptophan intake, namely niacin-equivalent intake. These phenomena were mainly attributed to the facts that the activity of liver 4-Pyr-forming MNA oxidase increased with improvement of amino acid intake and that this enzyme activity decreased with increasing niacin-equivalent intake because of inactivation during the catalysis. From the above results, it was pointed out that the increased urinary ratio of (2-Pyr+4-Pyr)/MNA can serve as a biological marker for adequate amino acid intake, but not for adequate niacin intake.
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Hiroshi TAGUCHI
Article type: Article
1990 Volume 64 Issue 1 Pages
19-25
Published: January 25, 1990
Released on J-STAGE: March 17, 2018
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A wide variety of nicotinic acid related compounds including it's structure analogues and substrates, reaction products, cofactors, inhibitors of the representative enzymes participated in niacin metabolism were analyzed by HPLC with ODS column at various pH and salt concentrations of the mobile phase. The retention times of these compounds were compared with UV- and radio-monitors. Then, these methods were applied to the determination of enzyme activities related to niacin metabolism and to the analysis of niacin related compounds in some foods and medicine. As the results, practical usefulness of these methods was proved. Especially, the radio assay of enzyme activities with radio monitor was demonstrated to be superb for it's very high specificity and sensitivity with accuracy beyond expectations. The data obtained in this study are helpful in the analysis of many kinds of nicotinic acid related compounds.
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Masaru TSUJIMURA, Tomoko FUKUDA, Harumi KOMATSUBARA
Article type: Article
1990 Volume 64 Issue 1 Pages
27-35
Published: January 25, 1990
Released on J-STAGE: March 17, 2018
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The pH values, total vitamin C contents, remaining vitamin C after heating at 100℃ for 5 min and the AsA oxidation capacity of 122 kinds (190 articles) of edible plant extracts which are commonly used in the daily life were investigated. For example spinach harvested in summer and winter were analyzed separately. Vegetables of 83 kinds and 112 articles; potatoes 4 kinds and 9 articles; and fruits 35 kinds and 69 articles were among those studied. When the pH values of extract was low, the oxidation volume was small. It was found that when the AsA/total vitamin C value of the extract was 10% or less, oxidation capacity was very high. So that 50% or more of total vitamin C could be retained when the extract was heated for 5 min under 100℃. It was necessary that the pH value is 6 or less and the oxidation volume of AsA is 500 μg/g or less.
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Akira MURATA, Rumi BABA, Masayoshi MATSUOKA, Hiroshi OTSUKA, Tohoru TA ...
Article type: Article
1990 Volume 64 Issue 1 Pages
37-43
Published: January 25, 1990
Released on J-STAGE: March 17, 2018
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A commercial multivitamin tablet containing 250 mg of vitamin C was daily administered for one week to six healthy adult males aged 20-24 years and the daily plasma concentration and urinary excretion of vitamin C were investigated. There was a significant increase in the plasma concentration and the urinary excretion on the first day, followed by further gradual increases during the week. The initial mean plasma value was 0.35 μg/100 ml indicating marginal vitamin C deficiency, and 0.87 mg/100 ml on the last day, which was a satisfactory level. The mean percentage of urinary vitamin C excretion increased from 24.7% in the first 24 h to 43.6% in the last 24 h after 7 day administration. However, there was considerable individual variation in the urinary vitamin C excretion. The hourly changes in plasma vitamin C concentration were compared between the first and last days of the administration. There was little differences in the plasma concentration-^time profiles except for the lower initial values on the first day. However, T_<max> (time to reach maximal concentration) became shorter, being about 2.8h on the first day and about 2.4h on the last day.
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1990 Volume 64 Issue 1 Pages
45-46
Published: January 25, 1990
Released on J-STAGE: March 17, 2018
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[in Japanese], E. Stang, R. Blomhoff, T. Berg, K.R. Norum
Article type: Article
1990 Volume 64 Issue 1 Pages
47-
Published: January 25, 1990
Released on J-STAGE: March 17, 2018
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1990 Volume 64 Issue 1 Pages
48-
Published: January 25, 1990
Released on J-STAGE: March 17, 2018
JOURNAL
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1990 Volume 64 Issue 1 Pages
48-49
Published: January 25, 1990
Released on J-STAGE: March 17, 2018
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[in Japanese]
Article type: Article
1990 Volume 64 Issue 1 Pages
49-
Published: January 25, 1990
Released on J-STAGE: March 17, 2018
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[in Japanese], [in Japanese]
Article type: Article
1990 Volume 64 Issue 1 Pages
51-
Published: January 25, 1990
Released on J-STAGE: March 17, 2018
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[in Japanese], [in Japanese]
Article type: Article
1990 Volume 64 Issue 1 Pages
51-52
Published: January 25, 1990
Released on J-STAGE: March 17, 2018
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1990 Volume 64 Issue 1 Pages
52-53
Published: January 25, 1990
Released on J-STAGE: March 17, 2018
JOURNAL
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[in Japanese], [in Japanese], [in Japanese]
Article type: Article
1990 Volume 64 Issue 1 Pages
53-
Published: January 25, 1990
Released on J-STAGE: March 17, 2018
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[in Japanese], [in Japanese], [in Japanese]
Article type: Article
1990 Volume 64 Issue 1 Pages
54-55
Published: January 25, 1990
Released on J-STAGE: March 17, 2018
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[in Japanese], [in Japanese]
Article type: Article
1990 Volume 64 Issue 1 Pages
55-
Published: January 25, 1990
Released on J-STAGE: March 17, 2018
JOURNAL
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[in Japanese]
Article type: Article
1990 Volume 64 Issue 1 Pages
57-
Published: January 25, 1990
Released on J-STAGE: March 17, 2018
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[in Japanese]
Article type: Article
1990 Volume 64 Issue 1 Pages
57-59
Published: January 25, 1990
Released on J-STAGE: March 17, 2018
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[in Japanese]
Article type: Article
1990 Volume 64 Issue 1 Pages
59-60
Published: January 25, 1990
Released on J-STAGE: March 17, 2018
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[in Japanese]
Article type: Article
1990 Volume 64 Issue 1 Pages
60-63
Published: January 25, 1990
Released on J-STAGE: March 17, 2018
JOURNAL
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