Chronic cadmium exposure during pregnancy in the mouse: influence of exposure levels on fetal and maternal uptake.

The uptake and distribution of orally administered cadmium-109 was studied in pregnant mice. Female outbred QS mice were given cadmium (Cd) supplemented drinking water for 1 mo before pregnancy and for the duration of pregnancy. The water contained either 0.0015 ppm Cd, 0.24 ppm Cd, or 40 ppm Cd. For the duration of pregnancy, 1.48 micrograms Cd/l (0.0015 ppm) in each solution was in the form of 109Cd (1 mCi/l). Control mice were given distilled/deionized water. On the day before term the mice were killed and a variety of adult and fetal tissues were examined in a gamma counter to determine their 109Cd concentrations. For each group the 109Cd concentration was highest in the maternal gastrointestinal tract, liver, and kidneys and lowest in the central nervous system (CNS) and blood. In general, the 109Cd concentrations in each organ were similar for each group of mice and were therefore independent of the overall oral Cd dose. A notable exception was the lower level in the duodenum in the 40 ppm group. In the fetal unit the chorioallantoic placenta contained the highest concentration of 109Cd. Concentrations in the fetuses were very low, comparable to those in the adult CNS. The 109Cd levels in the fetuses from group A were about fivefold greater than those of the fetuses from group C. There was no statistically significant evidence of specific localization in the fetal brain, kidney, or liver.