Copper accumulation and metabolism in primary monolayer cultures of rat liver parenchymal cells

Abstract

The characteristics of hepatic copper accumulation and metabolism were studied using primary monolayer cultures of adult rat liver parenchymal cells. Accumulation of copper from serum-free medium was temperature dependent and strongly inhibited by cyanide and N-ethylmaleimide. Addition of various concentrations of zinc to the medium did not alter copper accumulation by the cells. Furthermore, it was found that supplementation of the cell cultures with dexamethasone significantly stimulated zinc accumulation without affecting the accumulation of copper. Cycloheximide substantially stimulated accumulation of copper from the culture medium, whereas actinomycin D had no effect. Effux experiments showed that copper is rapidly sequestered by intracellular components and becomes unavailable for exchange soon after it is transported into the cells. Gel chromatography of liver cytosol demonstrated that most of the copper that is initially accumulated is bound to the low molecular weight cytoplasmic protein metallothionein.