Quantitation of acid phosphatase and aryl sulphatase in rat hepatic parenchymal and kupffer cells.

The two acid hydrolases ‘acid phosphatase’ (orthophosphoric monoester phosphohydrolase, EC 3.1.3.2) and ‘aryl sulphatase’ (aryl-sulphate sulphohydrolase, EC 3.1.6.1) are both enzymes which are known to be present in the lysosomes of almost all cell types [cf. l] . Histochemical studies have revealed apparent activity of acid phosphatase in both hepatic parenchymal and Kupffer cells [2,3] , and parenchymal liver cells have been claimed to show enzyme activity in granular form as revealed by light microscopy of sections incubated at pH 5 5 [4] ; however, histochemical methods have so far failed to reveal the situation in the Kupffer cells [5] . Evidence from studies of other tissues have suggested that lysosomes are heterogeneous with regard to content of lysosomal enzymes, and it has been claimed on the basis of results of histochemical studies that the distribution of aryl sulphatase may not completely agree with the distribution of acid phosphatase [4,6] . Furthermore, higher purification of aryl sulphatase than for instance acid phosphatase was obtained in lysosomes isolated from rat liver [7] . Methods have recently been worked out for the separation of parenchymal and Kupffer cells in highly purified fractions of rat liver [8-lo]. In the present study these methods were utilized with the aim of elucidating and comparing the activities of aryl sulphatase and acid phosphatase in the two main cell types of the liver.