Total serum copper and ceruloplasmin levels following administration of copper aspirinate to rats and guinea-pigs.

Total serum copper and ceruloplasmin oxidase activities have been measured over a 24-h period in rats and guinea-pigs treated with 100 mg/kg body weight of copper (II) aspirinate. In the rat, administration s.c. produced higher total serum copper levels than oral administration at all time intervals studied, whereas in the guinea-pig, oral administration produced the higher level after 1 h and s.c. administration the higher level after 5 h. In both species, the rate of elimination of the additional copper was faster following oral administration. Ceruloplasmin oxidase activity appeared to be inhibited in certain cases but rose in all cases except for orally treated rats after 24 h. The initial rise in serum copper was due mainly to copper present on albumin. The increased albumin copper was detected directly by electrophoresis of serum samples and subsequent determination of the copper level in the portions of the strip which contained proteins. After s.c. administration to the rat, the amount of ultrafilterable copper was raised by a detectable amount. 7 h after s.c. or oral administration of copper aspirinate, the thiol concentration of the serum was reduced in both rats and guinea-pigs. The relationship of these levels to the anti-inflammatory action of copper (II) aspirinate in rats and guinea-pigs is discussed.