Dietary restriction augments superoxide generation in mouse peritoneal macrophages: an investigation using a...

It has not been clarified whether dietary restriction alters macrophage functions, although the augmentation of T cell functions by dietary restriction is well known. Forty percent dietary restriction on 9-week-old male C3H/He mice caused a decrease of body weight. However, one of the major macrophage functions, the generation of superoxide anion (O2), was augmented in proteose peptone-elicited peritoneal macrophages (MPs) from diet-restricted mice. This increase was more striking when the cells were stimulated by 12-o-tetradecanoylphorbol-13-acetate (TPA), which directly activated protein kinase C, than by opsonized zymosan which binded to receptors on the cells. These results strongly suggest that the augmentation of O2- generation in MPs by dietary restriction is due to the increased activity of protein kinase C which phosphorylate and activate O2-generating enzyme system NADPH oxidase. It is thought that one of the major factors for the reduced incidence of tumor and infection in diet-restricted animals is the augmentation of O2-generation in MPs.