AJP - Renal Physiology, Vol 253, Issue 1 66-F75, Copyright © 1987 by American Physiological Society
Endogenous prostaglandins modulate autoregulation of renal blood flow in young rats
R. L. Chevalier, R. M. Carey and D. L. Kaiser
After uninephrectomy in the young rat, renal blood flow (RBF) increases at
normal renal perfusion pressure (RPP) but not at reduced RPP. To evaluate
the role of endogenous prostaglandins on these effects, RBF was measured
during reduction in RPP in rats that were uninephrectomized within 1 wk of
age and studied at 33-41 days of age. After acute cyclooxygenase
inhibition, autoregulation improved; RBF was unchanged at normal RPP but
increased at lower pressures with concomitant decrease in renal venous
plasma renin activity (PRA). Prostaglandin inhibition also improved
autoregulatory efficiency in acutely uninephrectomized and sham-operated
young rats. Infusion of a thromboxane synthesis inhibitor had no effect on
the pressure-flow relationship or on PRA, whereas angiotensin converting
enzyme inhibition increased RBF at all measured RPP without affecting
autoregulation. We conclude that increased RBF at normal RPP in the
uninephrectomized young rat is not maintained by increased prostaglandin
synthesis or decreased thromboxane- or angiotensin-dependent
vasoconstriction. However, by maintaining increased vasoconstriction at
reduced RPP, prostaglandin-dependent renin release reduces autoregulatory
efficiency in the young rat.
