OBSERVATIONS ON THE FUNCTIONAL HOMOGENEITY OF THE NEPHRON POPULATION IN THE CHRONICALLY DISEASED KIDNEY OF THE DOG*

Abstract

Glucose reabsorption has been measured during rising plasma glucose concentrations in dogs with one of 3 types of chronic unilateral renal disease. The glucose titration curves for the diseased kidneys were compared with those simultaneously obtained for the contralateral intact organs. Both in studies on individual animals and in a composite plot of group data for 12 experiments on 9 dogs, the patterns of diseased and contralateral kidneys were quite similar. Analysis of the group data demonstrated no appreciable titration splay for either diseased or normal kidneys; and no significant differences were found between the frequency distribution curves for the 2 sets of data. On the basis of these observations, it has been suggested that the balance between the volume of glomerular filtrate and the glucose reabsorptive capacity of the attached proximal tubules remained uniform for the surviving nephrons of the diseased organs, despite evidence of marked anatomic heterogeneity. Within the limitations of the glucose titration method, the residual functioning nephrons of the experimentally diseased kidney in the dog would therefore appear to constitute a basically homogeneous population.