Changes with age in cadmium and copper levels in C57BL/6J mice.

Cadmium concentrations in C57BL/6J male mice were found to increase with age in kidney from 0.1 ng/mg dry wt. at 45 days of age to 1.7 ng/mg dry wt. at 880 days of age. Cadmium in liver increased exponentially with age with a doubling time of 242 days, from a value of 0.03 ng/mg dry wt. at 45 days of age to 0.29 ng/mg dry wt. at 880 days of age. Kidney copper declined by only 14% between 45 and 400 days of age and remained unchanged between 400 and 880 days of age. Liver copper declined 41% between 45 and 500 days of age and showed no change between 500 and 880 days of age. Most of the decline in kidney and liver copper concentrations occurred before 240 days of age, possibly reflecting developmental changes. Feeding cadmium chloride in drinking water at concentrations of up to 100 microgram/ml did not change the copper concentrations in kidney, liver, heart or brain of young mice. Feeding copper gluconate did not change the cadmium concentration in livers of old mice. However, these treatments did change the cadmium/copper ratios in tissues.