Differences in Cu-Transport by Hepatocytes and Fibroblasts

Abstract

The liver rapidly and preferentially takes up Cu when administered orally or intravenously. Both kinetic and thermodynamic contributions may be involved. Kinetic factors are expected to determine the relative rates of Cu-transport by different cell-types. Thermodynamic factors may help determine the amounts of copper accumulated at steady-state. Kinetic studies with hepatocytes suggestgd that albumin-Cu was not directly available for Cu-uptake. Histidine increased Cu-uptake¹ from media which also contained albumin.^l Apparently, the His₂Cu complex which forms when histidine is in excess delivers Cu to a transport protein, and Cu is transported as the free ion. Cu-transport by fibroblasts is reported here as an example of Cu-transport by an extrahepatic cell type which is relevant to Cu-metabolism and Menkes disease.