Growth of rats during a subchronic intake of the heavy metals Pb, Cd, Zn, Mn, Cu, Hg, and Be.

Adult female SPF Sprague-Dawley rats were given 100 ppm Pb (CH3COO)2, CdCl2, MnCl2, ZnSO4, CuCl, Hg2(NO3)2, or BeSO4 for 91 days with their drinking water. The body weight gain of the rats changed during the 91 days of continuous inclusion of the heavy metal salts. During examination, body weights increased after the daily intake of MnCl2, ZnSO4 or BeSO4, but the other salts of Pb, Cd, Cu, Hg decreased the body weights, each compared with the controls. These effects were possibly caused by changes in feeding and drinking habits: The daily consumption of standard diet (pellets) increased during dosing with the salts of Mn, Zn or Be and decreased during treatment with the other heavy metal salts. The salts of Be and Mn enhanced consumption of drinking water, and the salts of Zn, Pb, Cu, Cd or Hg reduced consumption of drinking water, each compared with the controls. Most effective was Hg2(NO3)2. Perhaps, the heavy metal salts cause a change in the regulation of the appetite in the central nervous system.