TUMORIGENESIS IN F-1 OFFSPRING MICE FOLLOWING PATERNAL 12.5 CGY CF-252 FISSION NEUTRON-IRRADIATION

Experiments were conducted to determine whether following genetic dama ge at germ cell stages induced by paternal exposure to Cf-252 fission neutron could lead to tumorigenesis in the offspring. Seven-week-old C 3H/HeNCrj male mice were irradiated with 252Cf fission neutrons, at do ses of 0 and 12.5 cGy and were mated with nine-week-old C57BL/6NCrj fe males two weeks after the exposure. Three weeks later, it was found th at the proportion of abnormal sperm in the 12.5 cGy-irradiated males w as higher than that of 0 cGy-rradiated group. Embryo lethality among t he F-1 offspring was also found to be higher in the 12.5 cGy group tha n in the 0 cGy group, while the incidence of liver tumors among the F- 1 offspring increased in males only. These results suggest that the pa ternal 12.5 cGy radiation exposure may have caused genetic transmissio n of liver tumor-associated traits, which is in line with findings tha t show steep increase in incidence of tumorigenesis in B6C3F1.