239Pu metabolism in newborn and weanling pigs

Newborn (1-2 days old) and weanling (6 wk old) miniature pigs were injected intravenously with 239Pu citrate. Animals from each age group were killed at intervals over a 28-day period to obtain distribution and retention data. The most notable difference between the two age groups was in hepatic deposition and retention. One day after injection, the plutonium content of the liver in neonates was only one-third that in weanling pigs (4.3 vs 13.9% of administered 239Pu). Deposition and retention were not markedly different in individual skeletal components. Cumulative excretion during the first 7 days after injection was the same for each group--1.4% of the injected plutonium.