| Project/Area Number |
04454552
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
内分泌・代謝学
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| Research Institution | University of Tsukuba |
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Principal Investigator |
YAMASHITA Kamejiro Institute of Clinical Medicine, University of Tsukuba Professor, 臨床医学系・内科, 教授 (80015982)
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| Co-Investigator(Kenkyū-buntansha) |
KOKAI Yasuo National Children's Hospital, Chief of laboratory, 室長
MATSUSHIMA Teruhiko Institute of Clinical Medicine, University of Tsukuba Assistant professor, 臨床医学系・内科, 講師 (60199792)
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| Project Period (FY) |
1992 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥6,200,000 (Direct Cost: ¥6,200,000)
Fiscal Year 1994: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1993: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1992: ¥3,600,000 (Direct Cost: ¥3,600,000)
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| Keywords | Diabetes Mellitus / Complication / Aldose Reductase / Sorbitol / Myo-inositol / Hyperglycemia / PDGF / Eicosapentaenoic Acid / Na^+,K^+-ATPase / 高浸透圧 / トランスジェニックマウス / 分子生物学 / 蛋白精製 / バキュロウィルス / 部位特異的変異誘発法 / 蛋白工学 |
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| Research Abstract |
We investigated in this study the molecular mechanism of aldose reductase activity and the metabolic derangements in the diabetic status. The summary is shown as follows.
1. The role of His-42, His-188 and Lys-263 residues in the catalytic action of human aldose reductase was investigated in association with various inhibitors of this enzymes by site-directed mutagenesis. The mutated human enzymes were expressed in a faculovirus-insect cell system. The results are indicative of the possible role of Lys-263 in the substrate binding through electrostatic interaction.
2. Transgenic mice expressing human aldose reductase in several tissues including kidney and liver were examined. Histologically, capsular drop formations in glomeruli and thrombi in renal vessels were founds. Therefore, acceleration of aldose reductase activity might have an important role in the development of reveral diabetic complications.
3. We investigated the effects of high glucose and hyperosmolarity on platelet-derived growth factor (PDGF) production and PDGF-B chain mRNA levels in cultured human umbilical vein endothelial cells. Under an excess of ambient glucose and a hyperosmolar condition, PDGF concentrations in the culture medium were both significantly increased. Parallel to protein secretion levels, PDGF-B chain mRNA levels showed a significant increase. Thus, elevated PDGF released from endothelium by high glucose may play an important role the pathogenesis of diabetic angiopathy.
4. Based on these studies, we conclude that hyperglycemia nad the elevation of aldose reductase activity have a crucial role in the initiation and deterioration of diabetic complications.
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