Ovariectomy uncovers purinergic receptor activation of endothelin-dependent natriuresis

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Publisher: American Physiological Society
Document Type: Author abstract; Report
Length: 251 words

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Abstract :

We recently reported that natriuresis produced by renal medullary salt loading is dependent on endothelin (ET)-1 and purinergic (P2) receptors in male rats. Because sex differences in ET-1 and F2 signaling have been reported, we decided to test whether ovarian sex hormones regulate renal medullary ET-1 and P2-dependent natriuresis. The effect of medullary NaCl loading on [Na.sup.+] excretion was determined in intact and ovariectomized (OVX) female SpragueDawley rats with and without ET-1 or P2 receptor antagonism. Isosmotic saline (284 mosmol/kg[H.sub.2]O) was infused in the renal medullary interstitium of anesthetized rats during a baseline urine collection period, followed by isosmotic or hyperosmotic saline (1,800 mosmol/kg[H.sub.2]O) infusion. Medullary NaCl loading significantly enhanced [Na.sup.+] excretion in intact and OVX female rats. [ET.sub.A + B] or P2 receptor blockade did not attenuate the natriuretic effect of medullary NaCl loading in intact females, whereas [ET.sub.A + B] or P2 receptor blockade attenuated the natriuretic response to NaCl loading in OVX rats. Activation of medullary P2[Y.sub.2] and P2[Y.sub.4] receptors by UTP infusion had no significant effect in intact females but enhanced [Na.sup.+] excretion in OVX rats. Combined [ET.sub.A + B] receptor blockade significantly inhibited the natriuretic response to UTP observed in OVX rats. These data demonstrate that medullary NaCl loading induces ET-1 and P2-independent natriuresis in intact females. In OVX. activation of medullary P2 receptors promotes ET-dependent natriuresis, suggesting that ovarian hormones may regulate the interplay between the renal ET-1 and P2 signaling systems to facilitate [Na.sup.+] excretion. endothelin-1; purinergic receptors; renal medulla; sodium excretion doi: 10.1152/ajprenal.00098.2017.

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Gale Document Number: GALE|A504340395