Ionizing radiation has become a health concern emanating from natural sources like space travel and artificial sources like medical therapies. Although the risk of degenerative diseases by radiation has been reported, the detailed mechanisms are poorly understood. By revealing the underlying mechanisms, ionizing radiation can be used as a method to construct disease model systems. The regulation of adipocytes can be considered as a way to balance both glucose uptake and energy expenditure in order to derive the amount of fat stored. Thus, increases in glucose uptake or decreases in energy expenditure results in elevated fat deposition. In this study, we showed that cirradiation could trigger the biological response resulting in the fat accumulation of white adipose tissue in mice and that this can be a useful model for evaluation of anti-obestic drugs. To induce the fat accumulation by c-irradiation, 2-months-old female C57BL/6 mice were irradiated at 5Gy and further raised for 6 months.