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Kunihiro UEDA
Article type: Article
1991 Volume 65 Issue 5-6 Pages
213-226
Published: June 25, 1991
Released on J-STAGE: March 17, 2018
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ADP-ribosylation is a group of posttranslational modifications of proteins that have regulatory functions in the cell. In particular, poly(ADP-ribosyl) action or poly (ADP-ribose) synthesized on protein proved to play important roles in DNA repair, carcinogenesis, cell differentiation, and cell cycle events. Recent progress in the research of this variety of biological roles is reviewed on the basis of structure and function of poly (ADP-ribose) synthetase as revealed by molecular cloning techniques and by use of specific inhibitors.
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Yusuke HIDAKA
Article type: Article
1991 Volume 65 Issue 5-6 Pages
227-242
Published: June 25, 1991
Released on J-STAGE: March 17, 2018
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Regulation of squalene epoxidase in the cholesterol biosynthetic pathway was studied in human hepatoma cell line, Hep G2 and in rat liver. Incubation of Hep G2 cells with L-654, 969, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, increased squalene epoxidase activity, whereas low-density-lipoprotein (LDL) decreased it. In rat liver microsomes, cholestyramine feeding and the administration of reductase inhibitor to rats increased the epoxidase activity. Cholesterol feeding reduced it. These results demonstrate that squalene epoxidase is regulated by endogenous and exogenous sterols in Hep G2 cells and in rat liver. NB-598, a specific inhibitor of mammalian squalene epoxidase, was used to investigate the regulatory mechanism of cholesterol metabolism in Hep G2 cells. The inducibility by NB-598 in HMG-CoA reductase activity was rather low as compared to that by L-654, 969, though NB-598 inhibited cholesterol synthesis more potently than L-654, 969. On the other hand, the reductase mRNA was increased to the same extent. Therefore, NB-598 is thought to have no effect on the synthesis of nonsterol suppressor derived from mevalonate. NB-598 strongly increased LDL receptor activity. These observations indicate that squalene epoxidase inhibitor is expected to be highly effective in the treatment of hypercholesterolemia.
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Katsumi SHIBATA
Article type: Article
1991 Volume 65 Issue 5-6 Pages
243-248
Published: June 25, 1991
Released on J-STAGE: March 17, 2018
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Effect of dietary corn oil content on the urinary excretion ratio of (N^-methyl-2-pyridone-5^carboxamide + N^1-methyl-4-pyridone-3-carboxamide)/N^1-methylnicotinamide was investigated using rats. The male rats of the Wistar strain (3 weeks old) were fed on a 20% casein -0% corn oil, 20% casein - 5% corn oil (control) or 20% casein - 20% corn oil diet ad libitum for 41 days and the rats were then killed by decapitation. Urine samples were collected periodically. The excretion ratio was always statistically significantly higher in the 5% corn oil group than in the 0% and 20% corn oil groups and the liver N^1-methyl-4-pyridone-3-carboxamide-forming N^1-methylnicotinamide oxidase activity, which affects the excretion ratio, was statistically significantly higher in the 5% oil group than in the 0% and 20% oil groups. Accordingly, it was found that low of high dietary oil content lowers the excretion ratio of N^1-methyl-2-pyridone-5-carboxamide + N^1-methyl-4-pyridone-3-carboxamide)/ N^1-methylnicotinamide.
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Takashi UJIIE, Yukiko TSUTAKE, Kohei MORITA, Masako MATSUNO, Kaname KO ...
Article type: Article
1991 Volume 65 Issue 5-6 Pages
249-256
Published: June 25, 1991
Released on J-STAGE: March 17, 2018
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Vitamin B_1 contents in foods are determined by the thiochrome flurometric method (method 1) and high performance liquid chromatography with the post-column derivatization using potassium ferricyanide (method 2). In all foods studied, vitamin B_1 content determined by the method 1 agreed with the sum of 2-(1-hydroxyethyl) thiamin and thiamin contents determined by the method 2 (correlation coefficient=0.9996, n=43). 2-(1-hydroxyethyl)thiamin was newly found in dried purple laver, parsley, fish roe and Nameko. The contents of 2-(1-hydroxyethyl) thiamin and thiamin in pork, inside ham were recognized to be no change at +5℃ and -15℃ for 10 days. The destruction degree by heat depended on temperature and pH, and 2-(1-hydroxyethyl) thiamin was more sensitive to those factors than thiamin. It was found that a part of 2-(1-hydroxyethyl) thiamin was converted to thiamin by heat treatment.
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Article type: Appendix
1991 Volume 65 Issue 5-6 Pages
257-260
Published: June 25, 1991
Released on J-STAGE: March 17, 2018
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[in Japanese]
Article type: Article
1991 Volume 65 Issue 5-6 Pages
261-262
Published: June 25, 1991
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[in Japanese]
Article type: Article
1991 Volume 65 Issue 5-6 Pages
262-263
Published: June 25, 1991
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1991 Volume 65 Issue 5-6 Pages
263-265
Published: June 25, 1991
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[in Japanese]
Article type: Article
1991 Volume 65 Issue 5-6 Pages
265-266
Published: June 25, 1991
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[in Japanese]
Article type: Article
1991 Volume 65 Issue 5-6 Pages
266-267
Published: June 25, 1991
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[in Japanese]
Article type: Article
1991 Volume 65 Issue 5-6 Pages
267-268
Published: June 25, 1991
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[in Japanese]
Article type: Article
1991 Volume 65 Issue 5-6 Pages
268-
Published: June 25, 1991
Released on J-STAGE: March 17, 2018
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1991 Volume 65 Issue 5-6 Pages
269-270
Published: June 25, 1991
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[in Japanese]
Article type: Article
1991 Volume 65 Issue 5-6 Pages
270-
Published: June 25, 1991
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[in Japanese]
Article type: Article
1991 Volume 65 Issue 5-6 Pages
271-
Published: June 25, 1991
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1991 Volume 65 Issue 5-6 Pages
271-272
Published: June 25, 1991
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[in Japanese], [in Japanese]
Article type: Article
1991 Volume 65 Issue 5-6 Pages
272-
Published: June 25, 1991
Released on J-STAGE: March 17, 2018
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[in Japanese], [in Japanese]
Article type: Article
1991 Volume 65 Issue 5-6 Pages
273-275
Published: June 25, 1991
Released on J-STAGE: March 17, 2018
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[in Japanese], [in Japanese]
Article type: Article
1991 Volume 65 Issue 5-6 Pages
275-277
Published: June 25, 1991
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[in Japanese]
Article type: Article
1991 Volume 65 Issue 5-6 Pages
277-279
Published: June 25, 1991
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[in Japanese]
Article type: Article
1991 Volume 65 Issue 5-6 Pages
279-282
Published: June 25, 1991
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[in Japanese]
Article type: Article
1991 Volume 65 Issue 5-6 Pages
282-284
Published: June 25, 1991
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