DOSE DEPENDENCE OF GASTRO-INTESTINAL ABSORPTION AND BIOLOGICAL HALF-TIME OF CADMIUM IN MICE

Doses of cadmium varying from 1 μg Cd/kg body wt to 37.5 mg Cd/kg body wt were given to mice as a single dose of 109CdC12 by gavage. The whole-body retention of the administered dose was followed by whole-body counting during 4 months and thereafter the organ retention was determined at sacrifice. Mice given the lowest dose absorbed 0.5 percent of the amount of cadmium administered, mice given intermediate doses (15 μg Cd/kg body wt or 750 μg Cd/kg body wt) absorbed 1.4 percent, and animals given the highest dose absorbed 3.2 percent. The biological half-time of the retained dose of 109Cd was 70-90 days in mice from the low and intermediate dose groups and 2-3 times longer, i.e. 236 ± 40 days (mean ± S.D.) at the highest dose. The greater absorption and the longer biological half-time lead to a 10-fold higher proportion of the dose to be retained after 4 months in mice exposed to the highest Cd-dose, compared to mice given the lowest dose and to a 7-fold higher proportion compared to mice given the intermediate doses. The retention of radiolabelled cadmium in the organs of mice were increased accordingly. The liver/kidney Cd-ratios increased with dose. © 1979 Elsevier/North-Holland Scientific Publishers, Ltd.