Embryotoxicity of silver ions is diminished by ceruloplasmin--further evidence for its role in the transport of copper.

The effect of alimentary administration of silver salts upon embryogenesis in rats was studied. Feeding of female rats throughout the term on a regular diet supplemented with AgCl did not cause alterations of their physiological functions, despite the fact that enzymatically active copper-containing ceruloplasmin (CP) was eliminated from the blood plasma. However, developmental abnormalities of embryos, their prenatal death or the 100% mortality of the newborns in the first 24 h of life was seen. Copper content in placenta and fetal tissues was strongly diminished. Cu, Zn-superoxide dismutase (SOD) activity decreased in cytoplasm of embryonic cells along with a drop, though less pronounced, in the tissues of the pregnant females. Embryotoxicity of AgCl was seriously diminished by repetitive injections of native CP to the pregnant rats. Such treatment resulted in an increase of SOD activity in placenta and embryonic tissues. The mortality of the newborns also became less. It is suggested that the embryotoxic effect of AgCl is caused by its ability to interfere with copper metabolism, in particular by altering the copper-transporting function of CP.