Modification of the Clastogenic Effects of Cobalt by Calcium in Bone Marrow Cells of Mice in vivo

The interaction between cobaltous chloride and calcium chloride was observed using as endpoints mitotic index and frequency of chromosomal abonrmalities. The two salts were administered orally to laboratory-bred male mice in vivo singly or one followed by the other or both simultaneously. Chromosomes were studied from bone marrow preparations after 24 hr. In all cases, the administration of CaCl2 two hours before CoCl2 protected against the clastogenic effects of the latter to a significant extent. Simultaneous feeding of the two salts reduced the damage by CoCl2 only when CaCl2 was given in a higher concentration. The reduction of clastogenicity of cationic cobalt by calcium has been attribited to the competition between the two ions. This report of the use of Ca2+ in reducing the clastogenicity of Co2+ is a new one.