| Project/Area Number |
63560078
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
応用生物化学・栄養化学
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| Research Institution | Shizuoka University, Faculty of Agriculture |
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Principal Investigator |
SUGIYAMA Kimio Shizuoka Univ., Fac. of Agric., Associate Prof., 農学部, 助教授 (00126781)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1989: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1988: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | Sulfur-containing amino acids / Methionine / Cystine / Taurine / Cholesterol / Phospholipid / Free amino acids / ホスファチジルコリン / エタノ-ルアミン / コレステロール |
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| Research Abstract |
1. The effects of dietary sulfur-containing amino acids (methionine and cystine) on plasma cholesterol levels were investigated with rats fed cholesterol-free and cholesterol-enriched diets. It was found that the effects of sulfur-containing amino acids on plasma cholesterol levels mainly differ depending on kinds and amounts of sulfur amino acids, dietary protein level, and presence or absence of exogenous cholesterol.
2. The mechanisms by which dietary taurine and glycine lower plasma cholesterol levels were investigated. The effect of taurine, but not glycine, could be accounted for by stimulation of fecal bile acid excretion. It was suggested that the influence of glycine on methyl-group metabolism might participate in the plasma cholesterol-lowering effect of glycine.
3. The effects of methyl-group acceptors such as glycine, guanidinoacetic acid and nicotinamide on plasma cholesterol levels, PE N-methyltransferase and PC biosynthesis were investigated. The methyl-group acceptors improved methionine-induced hypercholesterolemia and depressed PE N-methyltransferse activity and incorporating of methyl-group of methionine. These findings indicated that the plasma cholesterol-elevating effect of methionine is due stimulation of PC biosynthesis via PE N-methylation pathway.
4. The effects of dietary methionine and protein source an plasma cholesterol levels were investigated in relation to hepatic free amino acid patterns. A significant correlation was found between plasma cholesterol levels and hepatic free ethanolamine levels. The results suggested that hepatic free ethanolamine reflects the influence of dietary methionine level on the synthesis and metabolism of phospholipid in the liver and on the plasma cholesterol level.
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