Interrelationships between cadmium, zinc and copper in human kidney cortex

The concentrations of cadmium, copper, and zinc have been determined in tissue samples of kidney cortex collected from 399 deceased persons autopsied in Dusseldorf and Duisburg, West Germany. The mean concentrations (geometric means) were: Cd: 17.0 μg/g wet weight (range <0.4-94.3 μg/g); Cu: 1.6/ μg/g (range 0.5-8.7 μg/g); Zn: 29.1 μg/g (range 6.3-91.6 μg/g). Zinc was shown to accumulate with age in the kidney cortex in a way similar to cadmium with peak concentrations at ages between 30 and 50 years. In contrast to cadmium and zinc, the copper content did not increase with age. The calculation of the regression line between individual cadmium and zinc concentrations, expressed as μmol/g wet weight, gave a slope constant 0.723 (regression equation: ZnKc = 0.723 CdKc + 0.342; r=0.46, P <0.001), which corresponds to a somewhat less than equimolar increase of zinc. There was a significant increase of the Cd/Zn ratio in kidney cortex during the first decades of life followed by a decrease at ages over 70 years. The “basal zinc”; content in kidney cortex showed a slight decrease until age 70 years followed by an increase at higher ages.