| Project/Area Number |
14406001
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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 | 海外学術 |
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| Research Field |
Environmental physiology (including Physical medicine and Nutritional physiology)
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| Research Institution | Akita University |
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Principal Investigator |
SENOO Haruki Akita University, School of Medicine, Professor, 医学部, 教授 (90171355)
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| Co-Investigator(Kenkyū-buntansha) |
SATO Mitsuru Akita University, School of Medicine, Associate professor, 医学部, 助教授 (60226008)
IRIE Toshiaki Akita University, School of Medicine, Research associate, 医学部, 助手 (90231167)
HIGASHI Nobuyo Akita University, School of Medicine, Research associate, 医学部, 助手 (60361218)
佐藤 岳哉 秋田大学, 医学部, 助手 (10312696)
今井 克幸 秋田大学, 医学部, 助手 (80006741)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥14,900,000 (Direct Cost: ¥14,900,000)
Fiscal Year 2004: ¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2003: ¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2002: ¥7,700,000 (Direct Cost: ¥7,700,000)
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| Keywords | Greenland / polar bears / vitamin A / hepatic stellate cell / food web / lipid droplet / gold chloride / autofluorescence / ダイオキシン / PCB / 環境汚染物質 / 臓器障害 |
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| Research Abstract |
To investigate the storage mechanisms of vitamin A, we examined the liver of adult polar bears and arctic foxes, which physiologically store a large amount of vitamin A, by high-performance liquid chromatography (HPLC), transmission electron microscopy (TEM) morphometry, gold chloride staining, fluorescence microscopy for detection of autofluorescence of vitamin A, staining with hematoxylin-eosin (H&E), Masson's trichrome, and Ishii-Ishii's silver impregnation. HPLC revealed that polar bears and arctic foxes contained 1.8-1.9 micro mole total retinol (retinol plus retinyl esters) per gram liver. In the arctic foxes, the composition of the retinyl esters was found to be 51.1 % palmitate, 26.6 % oleate,15.4 % stearate, and 7% linoleate. The hepatic stellate cells of the arctic animals were demonstrated by TEM to contain the bulk of the vitamin A lipid droplets in their cytoplasm. The liver lobules of the arctic animals showed a zonal gradient in the storage of vitamin A. The gradient was
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expressed as a symmetric crescendo-decrescendo profile starting at the periportal zone, peaking at the middle zone, and sloping down toward the central zone in the liver lobule. The density (namely, cell number per area) of hepatic stellate cells was essentially the same among the zones. The gradient and composition of the vitamin A esters in storing vitamin A were not changed by differences in the vitamin A amount in the livers. These results indicate that the heterogeneity of vitamin A-storage capacity in hepatic stellate cells of arctic foxes and polar bears is genetically determined. We also caught 4 polar bears in Ittoqqortoormiit, in the east coast of Greenland from July through August, 2004. We analyzed the lipid droplets in the hepatic stellate cells by morphological methods. The size and number of the droplets increased due to the aging; this showed the vitamin was accumulated chronologically. This result showed that the vitamin A was accumulated from the food and stored in the hepatic stellate cells. Less
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