Effect of copper deficiency on the activity levels of ceruloplasmin and superoxide dismutase in tissues of young and old rats.

Six- and 24-month-old rats were fed a copper deficient diet for 10 weeks; the copper content of the diet was one fourteenth that of a control diet. After the 10-week feeding period, the copper contents of the cerebrums, livers, lungs, and serum were decreased by 20-17, 49-47, 48-37, and 84-83%, respectively, while those of hearts and muscles were unchanged or only slightly decreased. There was no difference in the decreases in copper content of tissues between young and old rats. Copper deficiency decreased the activity level of ceruloplasmin in the serum of young and old rats by 95%, and the copper/zinc superoxide dismutase (CuZn-SOD) activity levels of cerebrums, lungs, and livers of young rats by 16, 36, and 34%, respectively, but did not change the CuZn-SOD activity levels of tissues of old rats. Although copper deficiency affected catalase activity, vitamin E concentration, and reduced glutathione concentration in several tissues, no consistent trends were observed. On the basis of the survival time of rats exposed to more than 96% oxygen, it is suggested that a decrease in CuZn-SOD activity due to copper deficiency increases oxygen susceptibility.