DISTRIBUTION AND FATE OF MN54 IN RAT, WITH SPECIAL REFERENCE TO CNS

In view of the still prevalent problem, in certain mining communities, of chronic manganese toxicity affecting the C.N.S., and the paucity of experimental data explaining the mechanism of this, the distribution and fate of isotopic Mn54 in different organs and tissues and in the whole body of the rat was studied over a period from 15 min to 34 days after intraperitoneal injection of an Mn54 maleate solution. While the curve for the whole body and for most organs could be resolved into two exponential components, the slower component was not present for the C.N.S. The blood seemed to serve as a transport medium receiving and discharging the Mn54 rapidly. While most organs showed a gradual decline with time in the counts per minute per gram of tissue and in the retained dose, the brain and the spinal cord exhibited a steady rise from the beginning to end. The suprarenal, pituitary, heart and bone also evidenced this to some extent. A greater capacity for relative retention of a small dose of manganese by the C.N.S. might be responsible for its selective vulnerability in chronic manganism. © 1969 The Physiological Society