Distribution of ²⁴¹am in offspring from BALB/c mice injected with ²⁴¹am at 14 days of gestation: Relation to calcium and iron metabolism and comparison with distribution of ²⁴¹am after injection of adults

Pregnant mice were given intravenous injections of ²⁴¹Am citrate at 14 days of gestation. The fetal skeleton had a higher or similar uptake of ²⁴¹Am per gram of fresh tissue than the liver. In comparison, the liver in adults concentrated 5 to 20 times more ²⁴¹Am per gram of fresh tissue than the bones. Measurement of changes in calcium and iron content and concentration with time, showed that in the developing mice intensive calcification of bones determined the uptake of ²⁴¹Am. The ²⁴¹Am uptake was related to the calcium concentration of the fetal bones, which was greater at 14 days of gestation in the anterior bones, the mandibles and calvaria, than in the ribs and femurs. Transfer of ²⁴¹Am to pups via milk resulted in further accumulation of ²⁴¹Am in the skeleton and liver. The incorporation in the skeleton persisted after weaning and contributed to the lifetime body burden. The ²⁴¹Am concentration decreased rapidly with time after injection in relation to the growth of the organs. Radiation dose rates and cumulative radiation doses were calculated for liver and bones of contaminated offspring.