1987 Fiscal Year Final Research Report Summary
Electron Microscopic Study on the Vitamin A-Storing Cells
| Project/Area Number |
61440023
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
General anatomy (including Histology/Embryology)
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| Research Institution | The University of Tokyo, The Institute of Medical Science |
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Principal Investigator |
HIROSAWA Kazushige The University of Tokyo, The Institute of Medical Science, 医科学研究所, 教授 (30009980)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUMOTO Emiko The University of Tokyo, The Institute of Medical Science, 医科学研究所, 助手 (20173891)
SAWADA Hajime The University of Tokyo, The Institute of Medical Science, 医科学研究所, 助教授 (90101112)
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| Project Period (FY) |
1986 – 1987
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| Keywords | vitamin A-storing cell / fat-storing cell, / vitamin A / Suncus s / small intestine / villous fibroblasts |
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| Research Abstract |
Vitamin A (VA), not synthesized by animals, is stored in the animal body. A main depot has been considered to be hepatic fat-storing cells, but in the case of hypervitaminosis A, it is also stored in fibroblasts of the lung, adrenal, gastrointestinal tract, et. We have defined these cells as "vitamin A-storing cell system". First of all, this working hypothesis is summarized in a paper titled " an introduction of vitamin A-storing cell system" in a Japanese journal. This topics has become international, and a symposium was held at Kyoto, Septemter 1986. Histological demonstration of VA-storing cells was further carried out on the liver of Watase threw. Though the cell number was smaller than that of ordinary laboratory animals, fat-storing cells were identified in the liver. (presented at 92nd annual meeting of Anatomists). In vivo and in vitro studies on the VA uptake by fibroblasts have been continued. An in vivo study of villous fibroblasts was done on the Suncus small intestine. We
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identified two types of fibroblast in the intestinal lamina propria; one was ^3H-VA labeled fibroblasts and the other was non-labeled ones. Serial sections were examined throughly, and a conclusion was reached that the non-labeled cells had no lipid droplets at all. Labeled cells were localized in the middle of lamina propria, while non-labeled ones were found beneath the basal lamina of epithelium. Serial sections of both types of cells were reconstructed three dimensionally with an image analyser, JIM 5000. This results will be published in the J. Electron Microscopy. Dissociated fat-storing cells were primary-cultured for several days and were administered with ^3H-VA in the culture medium. It was confirmed that cultured fibroblasts incorporated VA. The result was published in the "Hepatology" (Japanese text). Cutaneous fibroblasts were cultured and various concentrations of VA acetate were added. Even at a physiological concentration, in vitro fibroblasts incorporated VA into cytoplasmic lipid droplets. HPLC analysis revealed that the stored VA were palmitic and oleic esters. As the concentration increased, various non-physiological VA esters were found in lipid droplets, suggesting that VA metabolism was disturbed in the cytoplasm. The result will be published in the Exp. Cell Rex. Less
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