In order to investigate the behavior of the urinary tubule and its surrounding interstitial tissue belonging to a glomerulus with reduced or abolished function, light and electron microscopic as well as microdissection and microangiographic studies of nephrons deprived both of glomerulic and beginning parts of proximal convolted tubules (aglomerular nephrons) were carried out. Those aglomerular nephrons were induced in rabbits by burn of the superficial layer of renal cortex according to the method of Fu jimoto et al. (1978). The results obtained were as follows: 1. In the aglomerular nephron induced in this way, there developed disuse atrophy and sclerosis of the proximal part of the nephron ultimately absorbed by surrounding tissue, dilatation of the lumen of Henle's loop, especially of its ascending limb, and following transformation of distal convoluted tubule into solid cell masses. Development of foci of massive coagulation necrosis in the superficial layer of renal cortex brought about stenosis or occlusion of arterioles supplying these areas, inducing secondary anemic atrophy and sclerosis of the aglomerular nephrons as well as the adjacent well preserved renal tissue. 2. An observation by microdissection and other means revealed the process of regeneration and covering by tubular epithelium at the proximal end of aglomerular nephron, along with cystic dilatation of the ascending limb of the Henle's loop and stagnation of some precipitates in the lumens. 3. About 2 months after burn injury a solid mass of cells with clear cytoplasms associated with development of capillaries appeared in the terminal portion of aglomerular nephron. Electron microscopy demonstrated that these cells contained a decreased number of organelles with no distinct microvilli or basal infolding, suggesting no active secretion or reabsorption. 4. Microangiography and other examinations showed that arterioles draining the injured area became heavily constricted without thickening of the intima about 1 month after injury, followed by marked constriction due to thickening of the intima, which led to anemic atrophy and sclerosis of the tissue drained thereby.
