AJP - Regulatory, Integrative and Comparative Physiology, Vol 258, Issue 1 82-R86, Copyright © 1990 by American Physiological Society
Mechanism of prostaglandin E2-induced increase of proximal sodium reabsorption in the rat
Y. Kinoshita and F. G. Knox
Department of Physiology, Mayo Clinic, Rochester, Minnesota 55905.
Prostaglandin E2, when infused directly into the renal interstitium,
enhances sodium reabsorption by the superficial proximal convoluted tubules
of anesthetized Sprague-Dawley rats. The present study was designed to
investigate the role of angiotensin II in the prostaglandin E2-induced
stimulation of proximal sodium reabsorption. Micropuncture at the
superficial late proximal tubule demonstrated a significant increase in the
fractional reabsorption of sodium from 39.9 +/- 2.3% in control conditions
to 51.8 +/- 3.0% (n = 9, P less than 0.01) during the renal interstitial
infusion of prostaglandin E2. The stimulatory effect of prostaglandin E2 on
proximal sodium reabsorption was markedly attenuated by pretreatment with
saralasin. During intravenous saralasin infusion, prostaglandin E2 did not
significantly change the fractional reabsorption of sodium from 42.2 +/-
5.8 to 45.4 +/- 6.0% (n = 7, NS). In summary, the stimulatory effect of
renal interstitial infusion of prostaglandin E2 on proximal sodium
reabsorption was attenuated by pretreatment with saralasin. Therefore renal
interstitial infusion of prostaglandin E2 may enhance proximal sodium
reabsorption, at least in part, through stimulation of angiotensin II
production in the rat kidney.
