Developmental changes in hepatic copper proteins in the guinea pig.

We have suggested that Wilson's disease is caused by failure to adapt from the fetal to adult mode of copper metabolism and that the study of liver copper ontogeny might provide clues to the pathogenesis of Wilson's disease. This study traces the developmental changes in hepatic copper binding proteins in the guinea pig. During the last trimester, as fetal hepatic copper increases, metallothionein is the major copper binding peak in both the soluble and particulate supernatant fractions. After birth this peak decreases in parallel with the fall in liver copper. Metallothionein is absent from adult soluble supernatant and copper is associated with superoxide dismutase and a high molecular weight protein. A novel low molecular weight copper binding component is present in the particulate supernatant of neonatal liver, but is absent from the adult. Unlike many other animals, but similar to man, the switch from the fetal to adult mode of copper metabolism occurs at birth. Comparison of the copper protein profiles of the fetus and neonate with Wilson's disease are required to test the hypothesis that Wilson's disease is caused by developmental arrest of copper ontogeny.