1992 Fiscal Year Final Research Report Summary
Regulation Mechanisms of Metabolism of Essential Elements by Metal-Interactions
| Project/Area Number |
02454206
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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 |
Hygiene
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| Research Institution | Kansai Medical University |
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Principal Investigator |
TOKUNAGA Rikio Kansai Medical University,Department of Hygiene,Professor, 医学部, 教授 (40121959)
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| Co-Investigator(Kenkyū-buntansha) |
FURUKAWA Takako Kansai Medical University,Department of Hygiene,Instructor, 医学部, 助手 (00221557)
KOHNO Hirao Kansai Medical University,Department of Hygiene,Instructor, 医学部, 助手 (30148522)
TAKETANI Shigeru Kansai Medical University,Department of Hygiene,Assistant Professor, 医学部, 講師 (20121949)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Iron-bindig Protein / Ribosomal Protein / Ribonucleotide Reductase / Transferrin / Selenium / Transferrin Receptor / Heme Oxygenase / Lead |
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| Research Abstract |
We examined the properties of a new iron-binding protein purified previously from rat liver. The protein was digested with trypsin and the peptides were analyzed. The partial amino acid sequences of the tryptic peptides coincided with that of rat ribosomal protein P2. About 1.5% of radioactive iron in cells incubated with ^<59>Fe-transferrin was found in immunoprecipitates with anti-iron-binding protein serum. Exposure of Hela cells to arsenite or cadmium ions caused a marked increase in the synthesis of heme oxygenase, and the presence of sodium selenite suppressed the induction. These results indicated that selenium antagonizes the induction of heme oxygenase by heavy metals ions. Treatment of the cells with desferrioxamine resulted in decreases of ribonucleotide reductase activity, DNA synthesis, and cell growth. Exposure of the cells to anti-transferrin receptor antibody, 42/6, which blocks iron supplement into cells caused decreases of ribonucleotide reductase activity and DNA synthesis. When erythroleukemia (K562) cells were cultured with Pb^<2+>, the rate of cellular iron uptake from transferrin decreased to 46% of that in untreated cells. This reduction was the result of a decrease in the number of transferrin receptors on the cell surface also confirmed the decreased expression of transferrin receptors by lead-treated cells. The down-regulation of transferrin receptors by treatment with lead did not result from a decrease in the total amount of the receptor.
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