The rare earth elements are being used in the field of electronics, super conductors, alloys, nagnetic materials. and luminous materials. In order to investigate biological effects of rare earth elements distribution of these elements in organs of mice was observed after administration of rare earth compounds. The effects of the administration of these elements on the concentrations of biologically essential elements such as Ca. Mg. Zn. Fe. and P in organs was also observed.
1. Quantitative methods for determination of yttrium(Y) and lanthanide elements in biological materials were developed. After dissolving organs of mice by simple wetwashing procedure, Eu. Tb, or Dy complex with 2.6-pyridinedicarboxylic acid was measured by fluorometry. The detection limit of each element in this method was ; I ng/mi in Eu, I ng/ml in Tb, or 5 ng/ml in Dy.
2. All of the elements used (Y. La, Ce, Nd, Sm. Eu, Gd, Tb, Dy. Ho, Er, and Yb) were available to determine using ion chlomatography combined with
post-column reaction using arsenazo-III solution. The detection limit of this method was 2.5 ng in each element. Sensitivities for Eu, Tb, and Dy were increased 5-20 fold by using 2, 6-pyridinedicarboxilic acid solution as post-column reaction reagent in comparison with arsenazo-III solution.
3. The concentrations of Y or lanthanides in various organs of mice were determined after intravenous administration of their chloride compounds (25 mg element/kg body weight). Twenty hours after the administration, high concentrations of elements administered were found in spleen, lung, and liver. Similar organ distribution was found in mice administered 10 mg/kg Eu, Tb, of Dy. By the simultaneous administration of Eu, Tb, and Dy at 10 mg /kg each almost equql amounts of these elements were incorporated in spleen, as well as in lung and liver.
4. The increase of Ca concentration was clealy observed in spleen, lung, and liver in which high concentrations of administered elements were found. No significant changes in Mg, Zn, Fe, and P concentrations by the administration with the rare earth elements were observed in all organs tested.
5. The concentrations of administered elements and increase ratio of Ca concentration (administered/control) were different depending on the organ and element used. The relation between these changes and chemical or physical properties of rare earth elements, however, was not clear. Less