Subcellular localization of gadolinium injected as soluble salt in rats: a microanalytical study

The rare earth gadolinium (Gd) is used in modern industry. Solubilized DTPA Gd and DOTA Gd complexes are used as contrast media in nuclear magnetic resonance imaging. In order to determine the subcellular localization of Gd, rats were injected intraperitoneally with Gd nitrate. Two microanalytic methods, ion microanalysis and electron microprobe, enabled the distribution and the intracellular localization of Gd to be determined in the liver, spleen, bone marrow, kidneys and lung. The results showed: a) a punctual distribution of Gd in the tissues (liver, spleen, bone marrow and lung) as observed by ion microscopy; b) a selective concentration of Gd in the lysosomes of macrophages of the liver (hepatocytes), spleen (macrophages), bone marrow (macrophages) and lung (phagocyte cells), as determined by electron probe X-ray microanalysis. In all these sites the Gd is associated to phosphorus. Results are compared to those found for other rare earths and metal elements.