<b>Immunohistochemical localization of argininosuccinate synthetase in the liver of control and citrullinemic </b><b>patients </b>

Abstract

In order to clarify the pathogenesis of a quantitative reduction of argininosuccinate synthetase (ASS) protein in a specific type of citrullinemia. in Japan, immunohistochemical techniques were used to locate ASS in the liver of control and citrullinemic patients whose enzymatic analysis had already been performed. In the controls, ASS was located only in the cytoplasm of hepatocytes, but not in bile duct cells or endothelial cells, and was distributed almost homogeneously in the lobulus with slightly denser staining in the periportal region than in the pericentral region. Staining of the liver from patients with the quantitative type of citrullinemia indicated the presence of two types of abnormality. In the first group, the liver was stained more weakly than in the controls, but homogeneously in the lobulus. In the second group, the liver was stained heterogeneously in the lobulus showing a mixture of densely stained and lightly stained hepatocytes.