The effect of 110m Ag on ceruloplasmin oxidase activity in rats

The effect was studied of single i.v. injection of 110mAgNO3 (0.183 mg Ag+.kg-1 b.wt.) in rats on the ceruloplasmin (Cp) oxidase activity and copper serum concentration. It was found that Cp oxidase activity in the serum decreased to 70% of the control value and simultaneously serum copper concentration decreased to 30% of the control level. In both cases, the decrease was independent of the time elapsed after silver administration. Comparing these results with those reported recently in mice, Cu deficit in the rat serum was approximately twice as high. This fact is considered to be an inter-species difference. The concentration of copper in the hepatic supernatant significantly decreased (to eight times from the control value) after silver injection. Only less than 10% of the total amount of Ag found in the whole liver was taken up to the hepatic supernatant. Gel permeation chromatography of the supernatant (Sephadex G-75) revealed that no Ag-metallothionein fraction is present. On the basis of the results obtained it was concluded that the mechanism of silver inhibition of Cp oxidase activity still remains to be clarified. (author). 2 tabs., 1 fig., 7 refs