| Project/Area Number |
17H01967
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Eating habits
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| Research Institution | Ritsumeikan University (2019)
Nagasaki University (2017-2018) |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
山中 仁木 信州大学, 学術研究院総合人間科学系, 准教授 (30533921)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥17,680,000 (Direct Cost: ¥13,600,000、Indirect Cost: ¥4,080,000)
Fiscal Year 2019: ¥5,330,000 (Direct Cost: ¥4,100,000、Indirect Cost: ¥1,230,000)
Fiscal Year 2018: ¥7,280,000 (Direct Cost: ¥5,600,000、Indirect Cost: ¥1,680,000)
Fiscal Year 2017: ¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000)
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| Keywords | カルシウム / ビタミンD / ATP / 吸収 / 栄養 / 消化管 / 腸 / 腸上皮 / カルシウム吸収 / 小腸 / リン / ビタミンＤ |
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| Outline of Final Research Achievements |
Extracellular low phosphate strongly enhances intestinal calcium absorption independently of active vitamin D [1,25(OH)2D3] signaling, but the underlying mechanisms remain poorly characterized. To elucidate the phosphate-dependent regulation of calcium transport, we investigated part of the enteral environment that is involved in 1,25(OH)2D3-independent calcium absorption, which responds to dietary phosphate levels inmice that lack intestinal vitamin D receptor (Vdr) activity. We found that luminal ATP was regulated by the release and degradation of ATP at the epithelium, and phosphate restriction increased ATP release from epithelial cells via connexin-43 hemichannels. Furthermore, ATP degradation by ectonucleotide pyrophosphatase-1 was reduced, which was caused by the reduction
of theMAPKcascade.These findings indicate that luminalATP metabolismregulates transcellular calcium transport in the intestine by an 1,25(OH)2D3-independent mechanism in response to dietary phosphate levels.
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| Academic Significance and Societal Importance of the Research Achievements |
食品成分の消化・吸収のしくみは個別に解明されていても、実際の食品には様々な成分が混在し相互に影響しあうため、理論通りの吸収効率は得られない。食品成分による自律性カルシウム吸収調節の明確化は、栄養代謝への成分相互の影響を解明する上で有益な情報を提供する。 生体は栄養供給の過不足に常に迅速・柔軟に対応している。本申請研究で打ち立てた仮説が実証されれば、生体のカルシウム代謝の頑健性を生み出す腸上皮機能の理解を大きく進展させる。
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