ISSN:
1432-1041
Keywords:
l-Arginine
;
Nitric oxide
;
Hypertension
;
renal function
;
insulin
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Medicine
Notes:
Abstract The pressor, renal and endocrine effect of the physiological precursor of endothelial derived nitric oxide, l-arginine was compared, with a substrate inactive on nitric oxide, hypertonic d-glucose, in hypertensive patients. Ten mild-moderate essential hypertensives were assigned to either l-arginine (n−5) or d-glucose (n−5). Substances were infused over 25 min at equiosmolal rates preceded and followed by saline infusion for 25 min. Blood pressure and heart rate were monitored at 3-min intervals, while hormonal and humoral variables, inulin and paraaminohippurate clearance and electrolyte excretion were measured at the end of each period under conditions of maximal diuresis. l-arginine and d-glucose increased serum osmolality comparably and caused similar haemodilution to that with control saline. During l-arginine infusion, systolic and diastolic blood pressure decreased by 16.6% and 11%, respectively, and recovered in the postinfusion period. Heart rate, plasma renin activity, and plasma noradrenaline did not change significantly. The percent blood pressure decrement induced by l-arginine was significantly greater than that by d-glucose. Glomerular filtration rate was stable and renal plasma flow was increased by both substances. However, natriuresis, kaliuresis and chloruresis were markedly stimulated only by l-arginine, which also promoted the development of systemic acidosis, possibly as a consequence of hydrochloridric acid generated during its metabolism. Circulating insulin, atrial natriuretic peptide, growth hormone and glucagon levels were increased and plasma aldosterone was unchanged during infusion of l-arginine. Insulin was stimulated and the other hormones inhibited during infusion of d-glucose. The greater magnitude and the infusion-related time of the hypotensive action suggests a specific mechanism of action of l-arginine, independent of a changing osmolality. l-arginine-mediated hypotension occurred without evident reflexogenic sympathetic activation and was accompanied by marked natriuresis, kaliuresis and chloruresis without changes in glomerular filtration rate. Both l-arginine and d-glucose increased renal plasma flow comparably.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00198298
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