Proliferation of the reticuloendothelial system in the liver

Abstract

The rate of removal from blood of intravenously injected colloidal carbon was used to measure the functional capacity of liver phagocytes. The carbon disappearance rate constant was initially reduced and gradually returned to normal following injection into mice of saccharated iron oxide or colloidal carbon. This index of phagocytic activity increased above normal after zymosan, estradiol or bacterial endotoxin administration. To determine whether these increases were associated with cell proliferation, liver DNA synthesis was measured. Incorporation of radioactive phosphate into DNA of mouse livers rose markedly after administration of these substances. To characterize the cell type responsible for the large increases in DNA synthesis, radioautographs of liver sections were prepared from mice previously given tritium-labeled thymidine. The label was rarely seen in parenchymal cells, whereas many littoral cells were labeled.