Effects of inflammation on copper antioxidant enzyme levels.

Inflammation increases plasma levels of ceruloplasmin, a copper protein with possible antioxidant function. This paper describes modulation of these increases by copper intake, and describes combined effects of inflammation and copper intake on Cu-Zn and extracellular (EC) superoxide dismutase (SOD) activities. Turpentine injections in rats fed 1 of 4 copper levels increased ceruloplasmin activities, but values were sensitively limited by copper intake. Cu-Zn SOD activities in the liver, but not in erythrocytes or lungs, were reduced by inflammation in each dietary copper group. Inflammation in rats fed a standard mixed feed diet reduced plasma EC superoxide dismutase activities measured by inhibition of pyrogallol autoxidation. Different results were obtained with 3 xanthine oxidase based SOD assays which were each subject to assay interference. Studies in humans found a group of rheumatoid arthritis patients to possess relatively low erythrocyte SOD and relatively high ceruloplasmin activities. Activity levels of SOD, but not of ceruloplasmin, increased after 4 weeks of copper supplementation (2 mg/day). The fate of cellular Cu-Zn SOD activity contents in inflamed tissues is largely uninvestigated. However, interleukin-1, a hormone released at inflammation sites, elevated Cu-Zn SOD activities in cultured fibroblasts.