2007 Fiscal Year Final Research Report Summary
Effect of nutritional status of essential metals on intestinal absorption and tissue distribution of oral cadmium
| Project/Area Number |
17510050
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Risk sciences of radiation/Chemicals
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| Research Institution | Otani Womens University (2006-2007)
Kobe Gakuin University (2005) |
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Principal Investigator |
KYONG Son Min Otani Womens University, Faculty of Pharmacy, Associate Professor (60140406)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Keiichi Osaka Ohtani University, 薬学部, professor (90068247)
UEDA Hidenori Osaka Ohtani University, 薬学部, Assistant Professor (50419462)
TETSUTIKAWAHARA Noriko Kobe Gakuin University, Faculty of Nutrition, Research Associate (20299069)
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| Project Period (FY) |
2005 – 2007
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| Keywords | cadmium / essential metals / metal transporter / risk factor / nutritional status / metallothionein |
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| Research Abstract |
Dietary Cd intake is considered the main contributor to the body burden of Cd. However, numerous factors other than the quantity ingested affect the rate of intestinal absorption, organ retention, and body burden of Cd. To investigate host risk factors for body Cd accumulation, we studied the effect of the nutritional status of essential metals (EMs) on tissue accumulation of orally administered Cd. When mice received control or single-EM-deficient (DF) diets for 4 weeks, the concentration of each EM in either plasma or liver was significantly lower in each EMDF mice than in control mice. In contrast to that in FeDF mice, hepatic Fe concentration was significantly increased in other EMDF mice. Intestinal expression of divalent metal transporter 1 (DMT1) mRNA was in inverse proportion to hepatic Fe concentration in EMDF mice. Interestingly, although intestinal DMT1 mRNA expression was decreased, tissue Cd accumulation was significantly increased after oral Cd administration in all EMDF mice except those that received the FeDF diet. Hepatic Cd accumulation after oral Cd administration was not significantly increased in either EM-supplemented (EMSP) mice or control mice simultaneously dosed with each EM and Cd. These results indicate that Cd might be absorbed and accumulated through multiple pathways for maintaining EM homeostasis in the body. Therefore, DMT1 likely is not the sole transporter for Cd, and EM nutritional status is a risk factor for increased tissue accumulation of oral Cd.
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