A comparative study of lysosomal enzyme contents in blood and liver of rats following partial hepatectomy.

Lysosomal enzyme contents (acid phosphatase and beta-glucuronidase) in blood and liver were comparatively studied with histochemical methods after 70 per cent hepatectomy in rats. The major source of these enzymes released into the circulation was investigated. The serum lysosomal enzymes were substantially increased immediately after hepatectomy (6 and 12 hours), with the simultaneous peak elevation of serum glutamic oxaloacetic transaminase (SGOT). This increment decreased thereafter. However, the second significant increment was observed between 48 and 72 hours postoperatively, when SGOT activity was almost normalized. Histochemically, lysosomes in regenerating liver were significantly increased at 6 and 12 hours, mainly in the hepatocytes, and at 36 hours exclusively in the Kupffer cells, after hepatectomy, From these observations, the initial significant increment of lysosomal enzymes in the serum, seems to be due to enzymatic leakage following surgical trauma to the remnant liver. The comparative study may indicate that the major source of lysosomal enzymes released substantially into the circulation, from 48 to 72 hours, could be the Kupffer cells which contained numerous amounts of lysosomes at 36 hours following hepatectomy. A possible mechanism for the enzymatic release in our study seems to be "reverse endocytosis".