2004 Fiscal Year Final Research Report Summary
Development of methodology to study in vivo changes in polyamines levels and its application
| Project/Area Number |
13672261
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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 |
Physical pharmacy
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| Research Institution | Josai University |
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Principal Investigator |
SAMEJIMA Keijiro Josai University, Faculty of Pharmaceutical Sciences, Professor, 薬学部, 教授 (00072413)
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| Co-Investigator(Kenkyū-buntansha) |
NIITSU Masaru Josai University, Faculty of Pharmaceutical Sciences, Assistant Professor, 薬学部, 助教授 (00077976)
GODA Hitomi Josai University, Faculty of Pharmaceutical Sciences, Research Associate, 薬学部, 助手 (30170690)
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| Project Period (FY) |
2001 – 2004
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| Keywords | polyamine / spermidine synthase / inhibitor / IS-MS / regenerating liver / PCNA / stable isotope / trans-4-methylcyclohexylamine |
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| Research Abstract |
The purpose of this study was to examine the influence of in vivo inhibition of spermidine synthase(spd-syn) on the growth of rat tissues. This was because in vitro inhibition of spd-syn causes a similar change in spermidine(spd) and spermine(spm) levels to that observed whenever cell growth is arrested. First, the method of polyamine determination by ionspray ionization mass spectrometry was semi-automated to treat many samples, by developing the polyamine tracer method using ^<15>N-labeled polyamines and the method for determining N^1,N^<12>-diacetylspermine in the urine of cancer patients. Second, analogs of n-butylamine and trans-4-methylcyclohexylamine (4MCHA), which are potent competitive inhibitors at the putrescine binding site of spd-syn, were prepared and their inhibitory activities tested. This revealed that 5-amino-1-pentene(APE) and 4MCHA had the lowest IC_<50> value. In parallel with this research, the structure of the putrescine binding site was investigated. A possible
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three-dimensional structure of mammalian spd-syn, constructed with homology modeling and identification of the cysteine residues, showed the difficulty of designing an inhibitor from the active site structure. Third, APE and 4MCHA were administered orally to rats (once daily for 1 week), and 4MCHA alone showed a decrease in spd combined with a moderate increase in spm in rat tissues. The changes in spd and spm levels were dose-dependent, and the body-weight gain of the rats tended to decrease with increasing doses of 4MCHA. The altered polyamine levels were maintained during the extended 1-month period, with growth-dependent alteration. The results show it is possible to produce experimental rats with a higher spm:spd ratio than control rats to investigate the physiological significance of spd downregulation and spm upregulation in vivo. As an application, liver regeneration was compared between the model rats and control rats. The results showed that the inhibition of spd-syn repressed proliferation of the regenerating liver. Studies are now in progress. Less
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Research Products
(12 results)
