Distributions of 54Mn and 65Zn in mouse fetuses

Female mice on gestational day 17 were injected intravenously with a single dose of 54Mn or 65Zn solution, and organ distributions of these radionuclides in the fetuses were studied 3, 6, 24 and 48 hours after administration using gamma counting and macroautoradiography. The fetuses of a litter incorporated 19% of the administered 54Mn and 50% of the administered 65Zn in the uterus. The pancreas showed the highest concentration of 54Mn in fetuses, followed by the gastrointestinal tract, kidneys and liver. 54Mn distribution pattern in fetuses was similar to that in dams, but the uptake in the bone and brain seemed to be greater in fetuses than in adults. 65Zn was markedly accumulated in the fetal liver, while no detectable amount of 65Zn was found in the brain. Although fetal distribution of 65Zn was similar to maternal one, 65Zn concentrations in fetal tissues were generally higher than those in dams. (author)