ABSTRACT
Three sources contributing to the pool of ROS in animal cells are discussed in this chapter-ROS production by macrophages, respiration, and lipid peroxidation of mitochondrial polyunsaturated membranes. There is still some debate about the major pathways of production of ROS in the cell. This state of affairs is due in part to the multiplicity of routes of ROS production, complex chemistry of ROS, great variability and modulation of rates of formation of ROS by a given pathway, technical difculty in quantifying ROS production in living organisms, as well as multiple and often redundant mechanisms of ROS detoxication. The case of ROS production by macrophages was chosen because it is possible to denitively identify these disease-ghting cells as a major benecial source of ROS for killing pathogens in humans. However, chronic or excessive ROS production by macrophages can cause peripheral damage to cells, triggering disease.
