Comparison of clastogenicity of inorganic Mn administered in cationic and anionic forms in vivo

A comparison of the cytotoxic activity of cationic (MnSO4) and anionic (KMnO4) salts of inorganic manganese in the mouse in vivo indicated that the former was more strongly clastogenic than the latter. Mice were administered different doses of the salt orally over a period of 3 weeks. In general, both the frequencies of chromosomal aberrations in bone marrow cells and micronuclei were increased significantly by both salts. Sperm-head abnormalities showed a significant enhancement as well. The clastogenic effects were directly related to the concentrations used and were not markedly influenced by the duration of treatment. In view of the known affinity of Mn2+ for chromosomal components, it has been suggested that the effects were mediated by these ions produced directly from MnSO4 and indirectly from KMnO4 following conversion under acidic pH of the gastric juices.