The influence of age on the efficiency of delayed therapy with Ca-DTPA for cerium in rats.

The influence of age on the effectiveness of chelation therapy starting 24 h after cerium administration was studied in 2- and 6-week-old rats. 141Ce was administered IP, followed after 24 and 48 h by IP administration of trisodium calcium diethylenetriaminepentaacetate (Ca-DTPA). The whole body and organ retention of 141Ce was determined 6 days after its administration. The chelation therapy significantly reduced cerium retention in both age groups but was more efficient in older animals. This age-related effect was, however, less pronounced than after immediate treatment with DTPA observed in our previous experiments, indicating that age as one of the factors which influence the efficacy of chelation treatment is probably more important in conditions of early than in conditions of delayed therapy.