The role of the liver, kidney and duodenum in tolerance in the copper-loaded rat.

The purpose of this study was to help characterize the pathway of copper in the liver, kidney and duodenum during copper loading and unloading in the rat. Male Wistar rats were allocated randomly into four groups: Group A (control) was composed of 16 animals fed a normal rodent diet. Group B had 16 animals fed a high copper diet (1500 ppm copper). Four rats from each group were killed at 1, 5, 10 and 15 weeks. Group C had 4 animals fed the high copper diet for 5 weeks and normal diet for 5 weeks. Group D consisted of 4 animals fed the high copper diet for 5 weeks, normal diet for 5 weeks, followed by 5 weeks of high copper diet. At termination of each experimental period liver, kidney and duodenum were collected for histochemistry and copper analysis by atomic absorption spectrophotometry. Hepatic copper concentration in Group B rose to 726 +/- 170 micrograms/g after 5 weeks; renal and duodenal copper levels were 285 +/- 14 micrograms/g and 134 +/- 49 micrograms/g, respectively. A significant (P < 0.005) decrease in copper concentration was observed after 15 weeks in all three organs. Duodenal copper concentration in group C was similar to control rats. Changes in copper tissue distribution and efficient unloading were demonstrated in all copper-loaded groups in the three organs studied.