EFFECT OF A MATERNAL INJECTION OF PU-239 ON THE NUMBER OF CFU-S IN THE FETAL LIVER OF THE C3H AND BDF1 MOUSE

We investigated the effect of Pu-239 administered on day 4 of gestatio n on the number of CFU-S (spleen-colony forming units) in the foetal l iver on day 17 of gestation in the C3H and BDF1 mouse. CFU-S numbers i n the foetal liver were decreased significantly by Pu-239 at doses >30 kBq/kg body weight in the BDF1 mouse, but were not changed by up to 9 00 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 distributio n and concentration of Pu-239 between the foetoplacental units of thes e two strains. These findings suggest a strain difference in the effec t of Pu-239 alpha-irradiation on the development of the foetal haemato poietic systems in the mouse.