Phagocytic Response of Rat Liver Capillary Endothelial Cells and Kupffer Cells to Positive and Negative Charged Iron Colloid Particles

The purpose of the study was to examine whether the uptake of substances by Kupffer cells and capillary endothelial cells was related to the electrostatic charges of the substance. Morphologic observations were made on rat liver after introducing iron colloid particles of positive or negative charge with or without preliminary perfusion by Hanks' solution for removing blood. Iron colloid particles introduced into the portal vein without preliminary perfusion of Hanks' solution were taken up by Kupffer cells but not by capil-lary endothelial cells irrespective of the electrostatic charge, as revealed by Prussian blue reaction and by electron microscopy. In liver irrigated with Hanks' solution, the positive charged iron colloid particles were taken up by capillary endothelial cells, as well as by Kupffer cells. The negatively charged colloidal particles were taken up selectively by Kupffer cells but not by capillary endothelial cells. The mechanisms for the selective uptake of foreign sub-stances by reticuloendothelial cells and the pinocytic uptake of some sub-stances by capillary endothelial cells are discussed in relation to the electrostatic charge of the substances to which the cells show affinity.