INFLUENCE OF ZINC AND COPPER ADMINISTRATION ON METAL DISPOSITION IN RATS WITH CADMIUM-METALLOTHIONEIN-INDUCED NEPHROTOXICITY

Only a few studies have investigated the effects of the interaction be tween Cu, Zn, and Cd on the toxicity of Cd in vivo and the metabolism of these metals. The present study is concerned with these effects. Ob servations of the distribution of these metals in liver and renal cort ex and of their excretion in urine were made. Sixty male Wistar rats w ere divided into 10 groups of six (a full factorial design complemente d by a center point and a control group) and were administered Zn (0 o r 25 mg/kg body mass), Cu (0 or 12.5 mg/kg), and CdMT (cadmium--metall othionein; 0.1 or 0.4 mg Cd/kg) by sc injection. The rats were given Z n and/or Cu 24 hr prior to the CdMT injection. The data were analyzed by linear multiple regression. After CdMT injection, the Cd retention level was markedly reduced in renal cortex and increased in liver by C u pretreatment, while the urinary excretion of Cd was significantly lo wer in these rats. The levels of endogenous Zn in renal cortex and liv er increased significantly in rats pretreated with Cu. The production of MT in liver and renal cortex was induced more efficiently by Cu tha n by Zn. The results obtained may be of importance in understanding th e mechanism of CdMT toxicity and the potential influence of Zn and Cu on the chronic nephrotoxicity of cadmium. (C) 1994 Academic Press, Inc .