Intracellular distribution of copper and zinc in the liver of copper-exposed cattle from northwest Spain

Total liver Cu concentration had little influence on subcellular Zn distribution, with hepatic Cu concentrations being only moderately correlated with Zn concentration in the large-granule fraction. There was a strong association between the proportion of total Cu bound to metallothionein (MT) and the proportion of total Zn in the large-granule fraction, suggesting that Zn displaced from MT is taken up by the lysosomes for excretion. This pattern of Cu accumulation, as in sheep, may be due to the limited capacity for metallothionein binding of Cu and excretion in bile.