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Tubuloglomerular feedback responses to acute contralateral nephrectomy
R C Blantz1, O W Peterson, S C Thomson
1Department of Medicine, University of California, San Diego, School of Medicine, La Jolla 92093.
The American Journal of Physiology
|May 1, 1991
Summary
Following kidney removal, the remaining kidney adapts within hours. Tubuloglomerular feedback (TGF) mechanisms do not suppress, but may adjust to increased single-nephron glomerular filtration rate (SNGFR).
Area of Science:
- Nephrology
- Renal Physiology
Background:
- Unilateral nephrectomy necessitates adaptive changes in the remaining kidney to maintain function.
- Early adaptive events include anticipation of increased glomerular filtration rate (GFR) and renal hypertrophy.
Purpose of the Study:
- To investigate tubuloglomerular feedback (TGF) and single-nephron GFR (SNGFR) responses at 2-4 and 12 hours post-nephrectomy.
- To determine if TGF activity is altered during the early adaptive phase after contralateral nephrectomy.
Main Methods:
- Micropuncture and microperfusion techniques were used in rats.
- Late proximal tubule flow (VLP) was manipulated to assess TGF responses and SNGFR.
Main Results:
- At 2-4 hours post-nephrectomy, SNGFR was reduced, and TGF operating points shifted, suggesting activation.
- By 12-14 hours, SNGFR and flow rates increased, with TGF parameters not significantly different from controls.
- Increased urinary excretion did not correlate with TGF alterations.
Conclusions:
- TGF activity and sensitivity are not suppressed early after nephrectomy.
- Observed changes in TGF may be adaptive responses to increased SNGFR rather than causal factors for the filtration rate increase.