The lysosomal copper concentration in the liver in primary biliary cirrhosis.

The copper concentration in the lysosomes of periportal hepatocytes of nine patients with primary biliary cirrhosis was determined by X-ray microanalysis in ultrathin sections, the chlorine concentration of the embedding medium being taken as internal standard. A positive correlation was found between the lysosomal and the total liver copper concentration. No correlation was found between the lysosomal copper concentration and the grade of orcein staining for lysosomal copper-associated protein in paraffin sections. It is concluded that in contrast to the grade of orcein staining, the lysosomal copper concentration is a reliable measure of the total liver copper concentration in primary biliary cirrhosis.

Changes in lysosomes during ageing of parenchymal and nonparenchymal liver cells.

Intact and viable parenchymal and non-parenchymal liver cell preparations were isolated by enzyme perfusion techniques from young and old rats. The distribution of the lysosomal enzymes acid phosphatase, beta-galactosidase, cathepsin D, acid DNAse, and arylsulphatase B over parenchymal and non-parenchymal cells was determined. In addition, morphological and morphometric changes which occur in parenchymal cells with age were investigated. All lysosomal enzymes studied are present in both cell classes, but non-parenchymal cells possess much ligher activities per mg protein than do parenchymal cells. This phenomenon is most pronounced for cathepsin D with a 13-times higher specific activity in non-parenchymal cells. Electron microscopic observations demonstrated that the lysosomal activities in non-parenchymal cells can be attributed mainly to the large and numerous lysosomal structures in Kupffer cells. Parenchymal cells from old rats have higher lysosomal enzyme activities per mg protein than do hepatocytes from young rats. This observation is in agreement with the general increase with age in the cytoplasmic volume fraction occupied by lysosomal structures in parenchymal cells. In general, non-parenchymal cells show no increase in specific enzyme activities with age. The results obtained suggest an increase in the heterogeneity--in both appearance and enzyme content--of the lysosomal structures in parenchymal cells with age.