L-arginine analogues inhibit aldosterone secretion in rats.
L-Arginine analogues, e.g., NG-nitro-L-arginine methyl ester (L-NAME), increase arterial pressure and suppress renin release in the rat. On the basis of these observations, it was hypothesized that L-arginine analogues also would attenuate aldosterone secretion. This hypothesis was tested in anesthetized rats treated with L-NAME or NG-nitro-L-arginine (L-NNA, 185 mumol/kg ip). The aldosterone secretion rate, plasma renin activity, and adrenal blood flow were attenuated in rats treated with L-NAME and L-NNA compared with control animals. Similar experiments were performed in anephric rats to examine the effects of L-NAME on aldosterone secretion independent of the circulating reninangiotensin system. The administration of L-NAME reduced adrenal blood flow but failed to reduce aldosterone secretion in these anephric rats. Bilateral nephrectomy reduced plasma renin activity essentially to undetectable levels in these animals. In a third series of experiments, two groups of anephric rats were infused with angiotensin II (3 micrograms/kg body wt iv) to provide a stimulus for aldosterone secretion. Aldosterone secretion and adrenal blood flow were markedly reduced in angiotensin II-infused rats pretreated with L-NAME compared with the control anephric animals infused with angiotensin II. Overall these results suggest that L-arginine analogues attenuate aldosterone secretion by inhibiting the adrenal steroidogenic effects of endogenous or exogenous angiotensin II and/or by reducing plasma levels of renin/angiotensin.
Simmons
J C
JC
Department of Physiology, University of Missouri School of Medicine, Columbia 65212, USA.
Freeman
R H
RH
D000450:Aldosterone / Q000378:metabolism*; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000494:pharmacology; D008297:Male; D019331:NG-Nitroarginine Methyl Ester; D009392:Nephrectomy; D009569:Nitric Oxide / Q000037:antagonists & inhibitors; D019335:Nitroarginine; D051381:Rats; D017207:Rats, Sprague-Dawley
D000804:Angiotensin II; D019335:Nitroarginine; D009569:Nitric Oxide; D000450:Aldosterone; D001120:Arginine; D019331:NG-Nitroarginine Methyl Ester