Effect of 5-fluorouracil on liver and plasma vitamin A in female rats [proceedings].

at 250nm and/or bound cadmium. Thus the presence of cadmium-metallothionein in the liver cytoplasm of these animals seems unlikely. When PM 10-concentrated cytosol fiactions were dialysed against IOmM-sodium phosphate buffer, pH7.4, none of the cadmium passed through the dialysis membrane. By contrast, after attempts to fractionate the material with (NH4)*S04, dialysis of the redissolved pellets resulted in the loss of much of the cadmium through the dialysis membrane. Similarly, adjustment of the PM 10-concentrated fraction to a final concentration of 10% (v/v) trichloroacetic acid also caused the cadmium to become freely soluble in the aqueous supernatant. After removal of the trichloroacetic acid-insoluble material, these supernatant fractions were neutralized. When they were subjected to ultrafiltration with a PM 10 membrane, none of the cadmium was retained by the membrane. These results are consistent with the formation of a complex between cadmium and one or more components of high molecular weight, distinct in character from the lower-molecular-weight protein, metallothionein. A similar distribution of cadmium was observed when gill tissue from the same animals was fractionated in an analogous manner to that described above for liver tissue. The concentration of cadmium administered to the fish in these experiments was considerably lower than those used in other investigations in which a metallothionein response has been observed (Overnell et al., 1977; Marafante, 1975).