Yamaoka K, Sato E F, Utsumi K
Radiation Safety Group, Central Research Institute of Electric Power Industry, Tokyo, Japan.
Physiol Chem Phys Med NMR. 1994;26(3):205-14.
Four hours after 0.25 Gy X-irradiation, the enzymatic activity of copper and zinc activated superoxide dismutase (Cu/Zn-SOD) in the spleen of mature rats showed a significant quantitative increase (by 25%); this was accompanied by a marked increase (by 70%) in the mRNA for this enzyme as compared to the control (sham irradiation) group. Irradiation had no effect on the enzymatic activity of manganese activated superoxide dismutase (Mn-SOD). Moreover, the expression of the mRNA for Mn-SOD was similar to that of the unirradiated control group. On the other hand, the enzymatic activity of both Cu/Zn-SOD and Mn-SOD in the liver of fetal rats showed a significant quantitative increase (by 15-35%); the expression of the mRNA for the two species of SOD increased (by 20-30%) at 4 hours after 1 Gy X-irradiation as compared to the control group. These findings suggest that the increase in SODmRNA level is due to novel transcription of SODmRNA by low dose irradiation.
