Effects of a human dose of Ca-DTPA on removal of plutonium in rats

The effects of a daily recommended human dose (1 g per 70 kg body weight=30 μmol/kg) of calcium diethylentriaminepentaacetic acid (Ca-DTPA) on removal of plutonium from rats injected with different amounts of plutonium were examined. Sixty female wistar rats were preinjected with doses of 0.185, 0.37 and 3.7 x 105 Bq/kg of plutonium as a nitrate, and half of the rats of each dose group were injected with 30 μmol/kg of Ca-DTPA for 3 days, beginning 1 h after plutonium injection on the first day. The 24-h urine and feces of rats were collected. The amount of urinary plutonium excretion in the Ca-DTPA groups was found to be significantly greater than that in the respective corresponding control groups at day 1-3. The amount of urinary plutonium excretion in the Ca-DTPA group at the 1st day was increased in response to the plutonium injected dose (correlation coefficient: r=0.628, vs. r=0.573 in the control group), that accumulated in the Ca-DTPA group for 3 days was r=0.800 vs. r=0.669 in the control group), while their rates of plutonium injected dose were decreased. Such findings were not obtained in the feces measurements. In conclusion, a human dose of Ca-DTPA chelation therapy enhances plutonium excretion as increasing plutonium intake, however the excreted rate of plutonium intake is decreased. (author)