Effects of calcium and magnesium acetates on tissue distribution of carcinogenic doses of cadmium chloride in wistar rats

Abstract

Previous studies have shown that magnesium, unlike calcium, prevents cadmium carcinogenesis at the subcutaneous injection site, and that neither magnesium nor calcium has any significant influence on the production of testicular tumors by cadmium in rats. The present investigation attempts to disclose the nature of those different effects by comparing the results of administration of both physiological metals on the uptake and distribution of carcinogenic doses of cadmium in rats. Male Wistar rats received a single subcutaneous (s.c.) injection of 109CdCl 2 (0.02 mmol/kg or 0.04 mmol/kg) and s.c. injections (one daily) of calcium acetate (CaAcet; 0.16 mmol/kg), or magnesium acetate (MgAcet; 4 mmol/kg), or saline on the day before, the day of and the day after the 109CdCl 2 dosing. The concentration of cadmium in tissues was determined by gamma-counting on the 4th, the 15th and the 45th day after the 109CdCl 2 injection. The concentration of cadmium in tissues on day 4 was ranked as follows: liver > kidney > the injection site skin > pancreas > spleen > heart > lung > distant skin > testes > blood. Administration of CaAcet increased by over 20% and that of MgAcet decreased by over 30% the initial uptake of both cadmium doses at the injection site. Thus MgAcet may prevent cadmium carcinogenesis by inhibiting the uptake of cadmium by the injection site tissues. In the testis and in all other tissues investigated, except kidney, the effects of the physiological metals were reserved, CaAcet tended to decrease and MgAcet tended to increase the uptake of cadmium. CaAcet and MgAcet exerted no noticeable effects on the uptake of cadmium by the kidney. The observed results of CaAcet and MgAcet administration on the concentration of cadmium in distal tissues seem to depend on the alterations in cadmium uptake at the injection site.