L'hypertrophie compensatrice du rein : réaction différente de divers segments du néphron, et influence de tissue rénal laissé en place après section des vaisseaux, ou injecté dans le péritoine après homogénéisiation

White male rats between 5 and 7 months old, were nephrectomized unilaterally, and the increase of wet weight and mitotic activity in the remaining kidney were studied after various treatments. Animals received colchicine intraperitoneally 3 or 4 hrs before sacrifice. Renal weight was expressed per body surface. Nephron segments were well identified by PAS staining and Harris hematoxylin after fixation in ethylalcohol+formaldehyde+5% acetic acid (figg. 1-8). Between 10.000 and 20.000 nuclei were counted in the proximal tubule, convoluted part only (PCT), and between 10.000 and 30.000 in the distal convoluted tubule (DCT); the numbers of mitoses were registered. Results showed: 1)mitotic activity in the PCT is independent of that in the DCT in the same kidney. 2)No correlation exists between renal weight increase and mitotic activity either in a single tubular segment, nor in both segments combined; 3)the reciprocal of the generation time in both segments is normally distributed; 4)weight increase 2 and 7 days after operation is not modified by the presence of necrotizing kidney in the retroperitoneal space, nor mitotic activity after 2 days; 5)kidney homogenate administered intraperitoneally twice, corresponding to 2x 1/10 of a kidney, had no influence on weight increase. Mitotic activity in DCT was not changed significantly but variation s2 between animals was increased. In the PCT mitoses are significantly depressed from 9 per 1000 nuclei in control animals injected with saline, to 4.3 per 1000 after homogenate injections (p