X-ray microanalysis of pyroantimonate complexes in rat kidney.

X-ray microanalysis was employed to define the cation content of electron-dense pyroantimonate complexes that occur in the proximal tubule of the rat kidney, along the intracellular aspect of plasma membranes and within the interchromatin regions of cell nuclei, when exposed to potassium pyroantimonate [KSb(OH)(6)] in vivo. Standard micropuncture technics were utilized to perfuse single proximal tubules in vivo with KSb(OH)(6) before fixation with a glutaraldehyde-formaldehyde fixative. Unstained, 1000 A-thin sections cut from Epon-embedded material were viewed directly with transmission electron microscopy and then subjected to x-ray microanalysis to determine their elemental content. Calcium, magnesium and potassium ions, in addition to sodium ions, were also present within the electron dense pyroantimonate complexes. Heavy concentrations of potassium and antimony in unrinsed tissue, presumably in the form of KSb(OH)(6). complexes, probably resulted from nonspecific precipitation secondary to exposure to alcohol solutions during dehydration, since KSb(OH)(6), is insoluble in alcohol.