AJP - Renal Physiology, Vol 260, Issue 5 643-F649, Copyright © 1991 by American Physiological Society
Renal interstitial hydrostatic pressure and PGE2 in pressure natriuresis
J. M. Gonzalez-Campoy, C. Long, D. Roberts, T. J. Berndt, J. C. Romero and F. G. Knox
Department of Physiology, Mayo Clinic and Foundation, Rochester, Minnesota 55905.
The present study tested the hypothesis that the presence of renal
prostaglandin E2 (PGE2) is necessary for full natriuretic response to
increased renal interstitial hydrostatic pressure (RIHP) during increased
renal perfusion pressure (RPP). In control untreated
pentobarbital-anesthetized dogs (n = 7), fractional excretion of sodium
(FENa) was 1.17 +/- 0.48, 1.07 +/- 0.24, and 2.69 +/- 0.57% at RPP of 90,
122, and 148 mmHg, respectively. These changes in FENa were associated with
effective renal blood flows (ERBF) of 1.43 +/- 0.20, 1.49 +/- 0.23, and
1.99 +/- 0.40 ml.min-1.g kidney wt-1, respectively. Similarly, glomerular
filtration rate (GFR) was 0.53 +/- 0.10, 0.71 +/- 0.10, and 0.72 +/- 0.14
ml.min-1.g kidney wt-1, respectively. Treatment with indomethacin, a
cyclooxygenase inhibitor, significantly lowered FENa to 0.45 +/- 0.13, 0.77
+/- 0.21, and 1.19 +/- 0.59% at RPP of 91, 121, and 146 mmHg, respectively.
Additionally, indomethacin treatment lowered ERBF (0.51 +/- 0.15, 0.52 +/-
0.10, and 0.85 +/- 0.21 ml.min-1.g kidney wt-1) and GFR (0.28 +/- 0.09,
0.34 +/- 0.09, and 0.47 +/- 0.09 ml.min-1.g kidney wt-1) at low, middle,
and high RPP, respectively. PGE2 replacement (n = 6) into renal artery at
0.01 microgram.min-1.kg body wt-1 returned FENa, ERBF, and GFR to control
levels over the same range of RPP, whereas prostacyclin (PGI2) infusion (n
= 7) at the same dose did not. RIHP was 4.2 +/- 1.2, 4.2 + 0.5, and 7.5 +/-
1.7 mmHg with increasing RPP in control untreated group and increased to
similar levels with indomethacin treatment and during PGE2 or PGI2
replacement.(ABSTRACT TRUNCATED AT 250 WORDS)
