Influences of gold on zinc, copper and metallothionein kinetics in liver and kidney of the rat.

1. Single, very low dose of gold (500 micrograms/kg body weight) was given intramuscularly to male Sprague-Dawley rats (mean body weight: 200 g) as aurothiokeratinate (Auro-Detoxin(R) dissolved in 0.9% NaCl. 2. Blood, liver and kidney were samples at autopsy 0.5, 1, 2, 3, 6 and 12 h after the gold injection (six animals per time). 12 rats were treated with 0.9% saline only as controls. The zinc (Zn), copper (Cu), gold and metallothionein (MT) concentrations were determined in homogenates and cytosols of liver and kidney using atomic absorption spectrometry and gel chromatography, respectively. 3. The main changes in metal and MT concentrations occurred in the kidney, where an increase of gold was found 0.5 h after the injection, followed by an increase in Cu and MT concentrations after 6 h. Zn homeostasis did not change. 4. The results suggest that gold by itself induces an increase of MT-like peptides in the kidney cytosol, which was accompanied by an increase in the concentration of Cu mainly bound to these MT-like peptides.