Studies on the Biological Effects of Rare Earth Elements. V. Relationship between the Concentration of Rare Earth Elements and 9 Minerals in Various Organs in the Rat after Intravenous Administration of Dy, Eu, Yb and Y by Low or High Dose.

Abstract

The relationships of the concentration of rare earth elements (REEs) and 9 minerals (Ca, Mg, P, Fe, Na, K, Zn, Cu and Mn) in the liver, kidney, spleen, lung, femur and whole blood were investigated in the male rats of Wistar strain. High or low dose of dysprosium chloride (DyCl3), europium chloride (EuCl3), ytterbium chloride (YbCl3) and yttrium chloride (YCl3) was administered intravenously from the caudal vein. High doses were 20 mg/kg (as REEs) for Dy, Eu and Yb or 10 mg/kg (as REEs) for Y, and low doses were 10 mg/kg (as REEs) for Dy, Eu and Yb or 5 mg/kg (as REEs) for Y. These doses were similar to μmol of each REE per rat. The contents of REEs and 9 minerals in the liver, kidney, spleen, lung, femur and whole blood were estimated by the wet digestionICP-AES method 1 day after the intravenous administration. Results were as follows : 1) The concentrations and distribution rates (% of dose) of REEs in the liver, spleen and lung increased by several times in the rats administered high dose of Dy, Eu and Y [Dy (H), Eu (H) and Y (H)] contrary to the decrease of distribution rate of REEs in the kidney. Distribution rate did not change by dose in the rats administered Yb. 2) Ca concentrations in the liver, spleen and lung increased by several or several decade times in the rats of Dy (H), Eu (H) and Y (H) groups. There were the tendency of Na concentration to be higher and K concentration lower in these rats. Zn concentration in the liver increased slightly by REEs administration. There were no effects of REEs administration otherwise. 3) There were strong positive correlations (p<0.001) between REEs and Ca concentrations in the liver, spleen and lung in the rats administered Dy, Eu or Y ; Ca concentration increased proportionally to REEs concentration. There was no correlation between Ca and Yb concentration. Therefore, it was suggested that there might exist the threshold of REEs dose for the increase of Ca concentrations proportionally to REEs concentrations in the liver, spleen or lung, and the appearence of Yb toxicity might be different from other 3 REEs (Dy, Eu and Y) toxicities.