Dose-dependent stimulation and inhibition of proximal tubular sodium reabsorption by angiotensin II in the rat kidney
PJ Harris, JA Young - Pflügers Archiv, 1977 - Springer
PJ Harris, JA Young
Pflügers Archiv, 1977•SpringerThe effect of val 5-angiotensin II on steady-state sodium concentration gradients (Δc Na)
was studied in rat proximal tubules by stationary micro-perfusion combined with perfusion of
the peritubular capillaries. Angiotensin added to the peritubular perfusion fluid had a
biphasic action with stimulation of sodium reabsorption at low doses (10− 12–10− 10 M) and
inhibition at high doses (3× 10− 7–3× 10− 6 M). Stimulation of transport was also observed
with intraluminal angiotensin but only at a dose of 10− 9 M. Transepithelial potential …
was studied in rat proximal tubules by stationary micro-perfusion combined with perfusion of
the peritubular capillaries. Angiotensin added to the peritubular perfusion fluid had a
biphasic action with stimulation of sodium reabsorption at low doses (10− 12–10− 10 M) and
inhibition at high doses (3× 10− 7–3× 10− 6 M). Stimulation of transport was also observed
with intraluminal angiotensin but only at a dose of 10− 9 M. Transepithelial potential …
Summary
The effect of val5-angiotensin II on steady-state sodium concentration gradients (ΔcNa) was studied in rat proximal tubules by stationary micro-perfusion combined with perfusion of the peritubular capillaries. Angiotensin added to the peritubular perfusion fluid had a biphasic action with stimulation of sodium reabsorption at low doses (10−12–10−10 M) and inhibition at high doses (3×10−7–3×10−6 M). Stimulation of transport was also observed with intraluminal angiotensin but only at a dose of 10−9M. Transepithelial potential difference was calculated from the steady-state chloride distribution; no significant change was observed at low (10−11M) or high (10−6M) concentrations and a direct action on sodium transport is postulated. This biphasic effect is discussed in relation to the responses of the intact kidney to intra-renal infusion of angiotensin, and to the control of tubulo-glomerular feed-back.
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