Pigment epithelial cells in culture. Metabolic pathways required for phagocytosis

The phagocytosis of bovine rod outer segments as measured by the uptake of 3H-labeled outer segments was studied in a culture system. Phagocytosis was markedly inhibited by the lack of glucose and by two inhibitors of the tricarboxylic acid cycle-cytochrome system, dinitrophenol and malonate. Lactate production was increased in phagocytizing cells, but the hexose monophosphate shunt was not stimulated. The data support the conclusion that the tricarboxylic acid cycle and its associated cytochrome system play an important role as an energy source for phagocytosis in these cells. Compromise of this energy source rapidly leads to a suppression of the phagocytic process.