Plutonium in the Tissues of Foetal, Neonatal and Suckling Mice after Pu-administration to Their Dams

Summary

Twelve-week-old female (C3H × 101)F₁ mice were injected intravenously with an ultrafiltered solution of ²³⁹Pu in 1 per cent trisodium citrate, and mated to uninjected PCT males. The plutonium content was examined radiochemically and autoradiographically in placentae and foetuses on the 12th and 18th days of gestation, and in neonates during the 24 hours after birth and also at 18 days post-natally.

Plutonium was distributed in most tissues of the late foetus and the suckling as it is in adult mice. However, on both the 12th and 18th days of gestation the concentration in the yolk-sac splanchnopleure was much higher than in any other foetal tissue. The amount of ²³⁹Pu in 18-day-old sucklings was between two and seven times as great as in 1-day-old neonates because of ingestion of milk from the lactating dams. In the first litter following administration of the radionuclide to the dam, about 0·02 per cent of the plutonium injected was transferred to an individual offspring by the time of birth, and a further 0·08 per cent by the time of weaning.