“…Changes in the homeostasis of essential elements, especially zinc and copper, by toxic metals have been studied with a view to understand the harmful action of these elements on the organism. Disturbances in the metabolism of endogenous metals may be induced in experimental animals by the administration of cadmium (Bonner et al, 1979;Ha"atek et al, 1990;Chmielnicka and Sowa, 1996), inorganic mercury (Bogden et al, 1980;Chmielnicka and Komsta-Szumska, 1980;Chmielnicka et al, 1986), alkilmercury compounds Chmielnicka, 1981, 1985a,b;Chmielnicka et al, 1989), nickel (Chmielnicka et al, 1982), tin , bismuth (SzymanH ska et al, 1993), and lead (Victery et al, 1982;Zare & ba and Chmielnicka, 1989). The most signi"cant changes in the essential copper and zinc concentration in the liver and kidney are correlated with an increase in the level of metallothionein.…”