Abstract
The intraperitoneal injection of native hen's egg white into rats produces morphological changes in the proximal convolutions of the nephron. Normally rod shaped mitochondria are replaced by large dense granules. Previous studies are in disagreement concerning the relation of these granules to the mitochondria. In this work succinoxidase activity was measured using a quantitative tetrazolium method on acetone fixed sections of normal and treated rat kidneys. Osmium fixed sections from the same animals were studied with the electron microscope. At 24 hours after injection intracellular granules in proximal tubule cells are numerous and there is a 35% decrease in succinoxidase activity. The enzymatic decrease is shown to occur only in the proximal conrolutions. With the electron microscope structures are seen which appear to be transitional between mitochondria and granules. At 72 hours after injection the mitochondrial morphology and the enzyme content have returned to normal.