Change of glutathione peroxidase synthesis along with that of superoxide dismutase synthesis in mice spleens after low-dose X-ray irradiation.
We have previously demonstrated that the activity of superoxide dismutase (SOD), an antioxidant, is enhanced by low-dose X-ray irradiation in various organs of animals such as rats. Since SOD is an enzyme that mediates the dismutation of O2- to H2O2, the question as to whether the resultant H2O2 is further detoxicated into H2O and O2 or not must still be evaluated. Hence, we studied the effect of low-dose X-ray irradiation on the synthesis of glutathione peroxidase (GSHPx), which is an antioxidant that catalyzes this reaction. The results suggest that H2O2 produced by increased SOD activity can be detoxicated into H2O and O2 due to simultaneous enhancement of the GSHPx activity by X-ray irradiation at 20 cGy, in contrast to irradiation at 400 cGy. The results also show the enhancement in enzyme activities by induction of their synthesis shortly after irradiation at 20 cGy. Moreover, as this phenomenon was observed in BALB/c mice (which are more radiation-sensitive compared to other mouse strains) and radiation-resistant C57BL/6NJcl mice, it was considered to be a common phenomenon in the rat spleen.
Bio-Science Department Komae Branch, Abiko Research Laboratory, Central Research Institute of Electric Power Industry, 2-11-1, Iwado-Kita, Komae-shi, Tokyo 201-8511, Japan. yamaoka.criepi.denken.or.jp
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Yamaoka
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Kojima
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Takahashi
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Nomura
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Iriyama
D000818:Animals; D004307:Dose-Response Relationship, Radiation; D004790:Enzyme Induction / Q000528:radiation effects; D005979:Glutathione Peroxidase / Q000096:biosynthesis* / Q000235:genetics; D006861:Hydrogen Peroxide / Q000378:metabolism; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011836:Radiation Tolerance; D051381:Rats; D013045:Species Specificity; D013154:Spleen / Q000201:enzymology* / Q000528:radiation effects*; D013482:Superoxide Dismutase / Q000096:biosynthesis*
D012333:RNA, Messenger; D006861:Hydrogen Peroxide; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase