1999 Fiscal Year Final Research Report Summary
PHYSIOLOGICAL ROLES OF SELENIUM WITH SPECIAL REFERENCE TO GUINEA PIGS
| Project/Area Number |
10672111
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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 |
Environmental pharmacy
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| Research Institution | Kitasato University |
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Principal Investigator |
HIMENO Seiichiro Kitasato University, School of Pharmaceutical Sciences, Associate Professor, 薬学部, 助教授 (20181117)
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| Project Period (FY) |
1998 – 1999
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| Keywords | selenium / guinea pig / glutathione peroxidase / vitamin C / thioredoxin reductase |
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| Research Abstract |
To elucidate physiological roles of selenium (Se) as an antioxidant, the expression and functions of selenoproteins in guinea pigs were examined. The guinea pigs have two distinct characteristics ; i.e., extremely low activity of glutathione peroxidase (GPx), which is the major selenoprotein in other mammals, and an inability of synthesizing vitamin C.We found that othter selenoproteins than GPx such as phospholipid hydroperoxide glutathione peroxidase and thioredoxin reductase (TrxR) are expressed substantially in guinea pigs. This suggests that the expression of not all selenoproteins is suppressed in guinea pigs. The highest activity of TrxR was found in adrenal glands, which had the highest concentration of vitamtin C.We confirmed the ability of TrxR for reducing dehydroascorbic acid (DHA) in the presence of thioredoxin. The activity of TrxR in guinea pig tissues hardly decreased when subjected to a Se-deficient diet. Similarly, DHA-reducing was hardly affected by Se deficiency in guinea pigs. These results were in contrast with a marked reduction of both activities of TrxR and DHA-reduction in rats. Thus, Se-containing TrxR in guinea pigs may play an important role in maintaining a reduced form of vitamin C.
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