AJP - Renal Physiology, Vol 260, Issue 6 868-F873, Copyright © 1991 by American Physiological Society
Kinin and tubuloglomerular feedback in normal and hydronephrotic rats
P. Morsing and A. E. Persson
Department of Physiology and Biophysics, University of Lund, Sweden.
The role of bradykinin in resetting the tubuloglomerular feedback (TGF)
mechanism was studied with the stop-flow technique in control and
hydronephrotic Inactin-anesthetized rats. Glomerular function was assessed
by measuring stop-flow pressure (Psf); the maximal decrease in stop-flow
pressure (delta Psf) with increased loop of Henle perfusion and the
perfusion that elicited half-maximal delta Psf, the turning point (TP),
were determined. Bradykinin infusion resulted in resetting of TGF in both
control and hydronephrotic rats but in different directions. A decreased
sensitivity was found in control rats (TP increased from 18.6 to 26.4 and
16.8 to 22.1 nl/min on systemic and intratubular administration,
respectively). In hydronephrotic rats the sensitivity of TGF increased. TP
decreased from 19.9 to 15.2 nl/min with bradykinin administered
systemically and from 18.4 to 15.0 nl/min on intratubular administration.
These results show that exogenous kinin administration mimics the effects
of extracellular volume expansion on TGF resetting and demonstrate a
difference in resetting in hydronephrotic and control kidneys.
