Blood copper concentrations and cuproenzyme activities in a colony of cats

There is little published information on plasma copper and whole blood copper concentrations in cats, and except for extracellular superoxide dismutase (EC SOD), we are unaware of published values for cat cuproenzyme activities.

In this study we determined plasma and whole blood copper concentrations, plasma ceruloplasmin (CP), EC SOD and diamine oxidase (DAO) activities, and erythrocyte superoxide dismutase (RBC SOD) activity in a specific pathogen-free colony of cats. Results were evaluated for differences based on age and sex.

Blood was obtained from 20 adult cats (10 males, 10 females; >1 year of age) and 20 immature cats (10 males, 10 females; <1 year of age). Copper concentrations were determined using atomic absorption spectrophotometry. EC SOD and RBC SOD activities were determined using the pyrogallol oxidation method, and CP activity was determined by the oxidation of 0 dianisidine dihydrochloride. DAO activity was measured using a colorimetric assay. Differences among groups were analyzed using ANOVA.

There were significant differences in mean plasma copper concentration, and CP and DAO activities (P=.001,.0001, and.02, respectively) among the 4 groups of cats. No age differences were identified. Male cats had significantly greater mean (+/- SEM) plasma copper (15.4 +/- 0.9 micromol/L versus 11.3 +/- 0.6 micromol/L; P =.001) concentrations, and CP (66.8 +/- 2.9 U/L versus 39.7 +/- 2.1 U/L; P=.0001) and DAO (6.68 +/- 0.16 U/L versus 6.15 +/- 0.1 U/L; P =.03) activities compared with female cats. Males had significantly greater whole blood copper concentrations (16.16 +/- 0.55 micromol/L versus 13.36 +/- 0.52 micromol/L; P =.002) than female cats.

Differences exist between male and female cats with respect to blood copper concentrations, and CP and DAO activities.