1988 Fiscal Year Final Research Report Summary
The Biochemistry of Lipophorin: Lipophorin and Adipokinetic hormone
| Project/Area Number |
60440004
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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 |
動物発生・生理学
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| Research Institution | Hokkaido University |
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Principal Investigator |
CHINO Haruo Instit. Low Temp. Sci., Hokkaido Univ., Professor, 低温科学研究所, 教授 (00012253)
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| Co-Investigator(Kenkyū-buntansha) |
YAZAWA M. Faculty of Science,Hokkaido Univ., Lecturer, 理学部, 講師 (50101134)
TAKAHASHI K. Faculty of Agriculture,Hokkaido Uni., Assist Professor, 農学部, 助教授 (40001432)
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| Project Period (FY) |
1985 – 1988
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| Keywords | Locusts / long flight / Lipophorin / Apolipophorin-III / Adipokinetic hormone in vitro action of AKH / アポーIII / カルシウムイオン |
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| Research Abstract |
The major purpose of this research project is to elucidate the molecular mechanism of a long flight in insects such as locusts. We have previously found that when insect adipokinetic hormone (AKH) is injected to adult locusts, the loading of diacylglycerol by lipophorin from the fat body is stimulated to a large extent, which results in the dramatical shift of lipophorin density to a lower value and significant increase in size of lipophorin particles. In addition to these changes, the AKH injection causes the association of a low molecular weight apoprotein, apolipophorin-III (apo-III) with lipophorin. These changes in lipophorin induced by AKH seems to facilitate the supply of diacylglycerol as fuel to flight muscle.
In order to further elucidate the mechanism of AKH action, it is essntial to establish the in vitro system, in which the above mentioned action of AKH observed in vivo can entirely be demonstrated in vitro. We have recently achieved to establish the reconstracted incubation system in which the purified lipophorin and apo-III are incubated with the isolated fat body in the presence of AKH under the contineous supply of excess oxygen. We demonstrated using this system that 1) the action of AKH requires calcium ion, 2) the full action of AKH requires the addition of 9 moles apo-III per each mole lipophorin, 3) the action of AKH is all or nothing, 4) the presence of apo-III is essential for the action of AKH, and 5) the amount of diacylglycerol loaded by lipophorin depends on the amount of apo-III added.
The establishemnt of the reconstracted system seems to greatly facilitate to develop this research field including the elucidaton of physiological role of apo-III.
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