Glycosidases of rat Kupffer cells, hepatocytes and peritoneal macrophages

Abstract

The acid glycosidase content of rat liver Kupffer cells was compared with that of hepatocytes and resident peritoneal macrophages. Homogenates of all these cells were able to hydrolyze the p-nitrophenyl glycosides of N-acetylglucosamine, N-acetylgalactosamine, glucose, galactose, fucose and mannose, but not xylose. Activity was greatest against the N-acetylglucosaminoside. With Kupffer cell homogenates, most of the glycosidases behaved as if they were lysosomal enzymes. When expressed as rates of hydrolysis per 10(6) cells, activities against a given substrate by homogenates from the three cell types generally agreed within a factor of 2-4. Significant differences between cell types were found, however, when ratios of glycosidase activities were compared. Furthermore, even though the quantity of glycosidase per cell was similar in Kupffer cells and hepatocytes, the glycosidase concentrations were much higher in the former cells, since Kupffer cells are much smaller than hepatocytes.