Efficacies of intraperitoneal injection of stable manganese for enhancing the elimination of incorporated 54Mn was studied in mice. At the start of the experiment, each mouse was given 37kBq of 54Mn and initial whole-body radioactivities were measured. Forty-eight hours after the injection, mice were given intraperitoneally a single dose of stable manganese at 0.3, 1.0, 3.0 and 10mg/kg, respectively. Then Whole-body retentions and principal organ distributions were measured at suitable intervals.
Whole-body retentions of 54Mn decreased markedly following the stable manganese injection, and the efficacies for elimination were estimated to be 45.3% for 0.3mg/kg, 59.6% for 1.0mg/kg, 71.4% for 3.0mg/kg and 78.0% for 10mg/kg. The substitution rates of incorporated 54Mn for the injected stable manganese were 61.5, 70.8, 79.5 and 83.7%, respectively, suggesting that most of the manganese exists in free or exchangeable state in the body. The concentrations of 54Mn in organs also decreased by stable manganese injection, however, the efficacies for elimination varied with organs. It was generally effective in the soft tissues, and it was ineffective in the bone.
In conclusion, intraperitoneal injection of stable manganese was very effective to eliminate the incorporated 54Mn and it could reduce the risk of possible future biological effects.
