Subcellular localization of aluminum and indium in the rat kidney

Previous studies. using electron probe microanalysis (EPMA) have shown that several elements are selectively concentrated in the lysosomes of the proximal tubule cells (PTC) of the kidney. In these lysosomes the elements are precipitated as nonsoluble phosphate salts, before being eliminated with the urinary flow as submicroscopic particles. However, in these studies, large. sub-toxic doses were administered, and this particular mechanism of "concentration-precipitation-elimination" was not initially considered as a physiological process, but, only as a pathological consequence of the toxic doses. Due to the high sensitivity of secondary ion mass spectrometry (SIMS), images can be obtained representing the distributions of these elements at a concentration several orders of magnitude lower than that required by EPMA.