Effect of a maternal injection of 239Pu on the number of CFU-S in the foetal liver of the C3H and BDF1 mouse.

We investigated the effect of 239Pu administered on day 4 of gestation on the number of CFU-S (spleen-colony forming units) in the foetal liver on day 17 of gestation in the C3H and BDF1 mouse. CFU-S numbers in the foetal liver were decreased significantly by 239Pu at doses > 30 kBq/kg body weight in the BDF1 mouse, but were not changed by up to 900 kBq/kg in the C3H strain. Quantitative autoradiography on days 6, 8 and 10 of gestation and liquid scintillation counting on days 13 and 17 of gestation revealed no significant differences in the distribution and concentration of 239Pu between the foetoplacental units of these two strains. These findings suggest a strain difference in the effect of 239Pu alpha-irradiation on the development of the foetal haematopoietic systems in the mouse.