Ultrastructural cytochemistry of the ischemic (endocrine) kidney.

Partial ligation of the aorta between the renal arteries induces marked atrophy of the cortical tubules (including the macula densa) of the left (endocrine) kidney with a remarkable increase in the number and granularity of hypersecretory juxtaglomerular granulated cells (JGC) which are found not only at the glomerular pole of arterioles but also in the walls of arteries and arterioles far removed from the glomerulus. Staining of fine sections of Araldite-embedded endocrine kidneys according to the periodic acid-thiocarbohydrazide-silver proteinate technique of Thiery reveals abundant glycogen in the JGC and less in the blood vessels and tubules. Juxtaglomerular granules are argentaphobic, but their rim is positively stained when ultrathin sections of glutaraldehyde-fixed, glycol methacrylate-embedded kidneys are exposed to phosphotungstic acid at a low pH. A positive reaction is also shown by the cell coat and lysosomes of JGC as well as by the thickened basal lamina, cell coat, cytosomes, and cytosegresomes of the atrophic tubules. Atrophy is most pronounced in the proximal convoluted tubules, which lose their apical microvilli, their basal infoldings and the majority of their mitochondria and cytosomes.