Evaluation of the Cell Separation Hypothesis of Autoregulation of Renal Blood Flow and Filtration Rate

Glucose Titrations in Normal and Anemic Dogs

¹ From the Department of Physiology, Cornell University Medical College, New York City

Glucose titrations were performed in dogs at normal and low hematocrits. The relationship between glucose load and tubular reabsorption was analyzed for splay. The splay was no greater with low than with normal hematocrit, demonstrating that nephrons saturate at the same plasma level of glucose, despite variations in red cell concentration. This is interpreted to mean that the glucose filtering capacities of glomeruli are matched to the reabsorptive capacities of their attached tubules with both normal and low hematocrits. Pappenheimer and Kinter have suggested that plasma skimming within the interlobular arteries plays an important role in autoregulation of glomerular filtration rate and renal plasma flow. Our data are inconsistent with any significant degree of preglomerular plasma skimming in dogs with normal hematocrit.

Note:
with the technical assistance of Anita Maceo and Marianne Aebli