Oral toxicity of methylcyclopentadienyl manganese tricarbonyl (MMT) in rats

Rats were given a single oral dose of MMT diluted in Wesson Oil. Eight groups of animals were used and the dosages varied from 15 to 150 mg/kg body weight. Necropsies were performed and tissues were taken for histopathological and Mn determinations from animals dying during the study and from a selected number of animals euthanatized at the end of the study. The $\text{LD}{}_{50}\text{14}$ was 58 mg MMT/kg body weight. Histopathological changes were found in the lungs, liver and kidney. The severity of the changes was related to the dose. Concentrations of Mn in selected tissues were elevated in animals dying from exposure. At 14 days post ingestion, the Mn concentrations had fallen to approximately normal values.