Abstract
We previously reported a significant increase in body weights in B6C3F1 female mice continuously exposed to low dose-rate (20 mGy/ 22 h/ day) gamma-rays as compared to that of age-matched non-irradiated control mice. To clarify the underlying mechanisms of body weight gain observed after exposure to continuous low dose-rate irradiation, we examined adipose tissue weights, liver and serum lipid contents, and factors related to glucose and lipid metabolism (serum insulin and adipocytokines), as well as ovarian dysfunction in female B6C3F1 mice continuously irradiated with gamma-rays at 20 mGy/ 22 h/ day from 9 to 44 weeks of age. Significant body weight gains, related to tissue adiposity, were observed from 28 to 44 weeks of age (accumulated dose = 2.7–4.9 Gy) in the irradiated mice as compared to those of non-irradiated mice. Histopathological analyses of ovaries and vaginal smears showed depletion of viable oocytes leading to premature menopause occurs at the same period when increased body weight gain was observed in the irradiated mice. These results suggest a possibility that the radiation-induced premature menopause could trigger the induction of body weight gain due to adiposity in B6C3F1 female mice continuously irradiated with low dose-rate gamma-rays at 20 mGy/ 22 h/ day. This study was performed under contract with Aomori Prefectural Government, Japan.
