Studies on the distribution of 137Cs in rats (II)

In this paper, the distributions of 137Cs in the pregnant rats and the parent rats during lactation are studied and discussed in comparison with the distribution in normal rats. The percentage of retention was observed to be lower with the pregnant rats than with the non-pregnant normal ones. The transfer of 137Cs to the fetus after the administration of 137Cs to the pregnant mother and the transfer of 137Cs to the baby from the parent during lactation after the administration of 137Cs to the parent are also studied. The fetus showed relatively low concentrations as compared with the pregnant mother. The tissue concentrations of the organs except blood were higher with the normal in the ratio roughly about two to one as compared with the parents during lactation. However, the concentration in blood was much higher with the rats during lactation than with the normal. Therefore it may be inferred that the tissue concentrations of the baby rats tend to be in equilibrium with those of the parent during lactation, if the baby is continuously fed with the milk of the parent that is receiving a continuous supply of 137Cs.