AJP - Renal Physiology, Vol 243, Issue 4 393-F403, Copyright © 1982 by American Physiological Society
Glucose transport in chronically altered rat nephrons
R. A. Kramp and W. B. Lorentz
Microinjection experiments were performed in anesthetized rats to study the
tubular absorptive capacity for glucose (TG) in normal and chronically
altered tubules, i.e., tubules that sustained anatomical repair and
compensatory changes of their previously normal configuration after acute
damage. TG was complete when the glucose load injected in normal or altered
early or late proximal convolutions was less than or equal to 1.5 or less
than or equal to 10 pmol . s-1, respectively. In normal tubules, TmG was 10
and 5 pmol . s-1 after early and late proximal microinjections,
respectively. After early proximal microinjections in altered tubules,
different levels of TmG were found. They related to the degree of
compensatory growth. TmG was approximately 12, 24, or 35 pmol . s-1,
respectively, in altered tubules with minor, moderate, or major
compensatory growth. After late proximal microinjections, TmG was 15 pmol .
s-1. TG variability was greater in altered than in normal tubules.
Correlation between structural and functional compensatory changes was thus
demonstrated. Furthermore, an important, albeit latent, absorptive capacity
for glucose of the proximal straight tubule was found.
