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<000.1); 6)Glucose in the drinking water stimulated mitotic activity in the DCT; 7)Parenteral NaCl 8.5/1000 stimulated mitotic activity in PCT. A formula is proposed that represents the accumulation of mitoses under colchicine administration. Available evidence for mechanisms of compensatory hyperplasia is discussed, and our results under 5) are seen to support mitotic control by internal secretion.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