Abstract
Under conditions in which the activity of the reticuloendothelial system is enhanced, acid and alkaline phosphatase activities of the mouse liver are increased. The acid phosphatase activity is localized in Kupffer cells, whereas the increased alkaline phosphatase activity is found within the endothelial linings of sinusoids. Changes in alkaline phosphatase activity occur earlier than those in acid phosphatase activity. The increase in acid phosphatase, but not the increase in alkaline phosphatase activity, could be inhibited by cortisone. Similar changes in alkaline phosphatase activity have been observed following histamine or serotonin injections and after partial hepatectomy. Peritoneal cells from mice infected with B.C.G. strain tubercle bacilli display more acid phosphatase activity than such cells from normal mice.