In vitro effects of hormones and autacoids on the hydrogen peroxide production and the morphology of endotoxin-activated rat peritoneal macrophages

Peritoneal macrophages activated in vitro by endotoxin exhibit alterations of their capability to produce hydrogen peroxide after phorbol ester stimulation when certain hormones or autacoids are present in the culture medium. They also show morphological changes, mainly concerning cell size and nuclear appearance. Agents known to increase the intracellular levels of cyclic AMP, e.g. adrenalin and PGE2 reduce the hydrogen peroxide production. Insulin, which is known to decrease cyclic AMP levels, produces opposite results. Agents postulated to act via phospholipase C, e.g. serotonin, augment the production of hydrogen peroxide. We assume that this form of modulation may represent a regulatory mechanism of macrophage activation.