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. Copyright (C) 1998 Elsevier Science B.V.