[Effect of large doses of manganese on erythropoietic activity]

The effect of intraperitoneal administration of 3 different doses of MnCl2 on erythro-poiesis was investigated in rats. Significant changes in 59Fe uptake by erythrocytes, bone marrow and spleen were observed in rats given the highest dose of 1 mg Mn/100 g of body weight. Six injections were necessary to produce a rise in the basic haematological indices, with the exception of reticulocytes whose number changed considerably during the period of investigations. The results of rat plasma filtrate administration to mice and total circulating blood volume determination which was unchanged after administration of MnCl2 suggested that the observed effects were produced by manganese. Histological examination of the liver, spleen and kidneys showed congestion and stasis of blood in them, especially in glomerular vessels.