Renal response to L-arginine in salt-sensitive patients with essential hypertension.
This study examined whether disturbances in nitric oxide formation contribute to renal dysfunction in salt-sensitive essential hypertensive patients. We evaluated the effects of intravenous administration of L-arginine (500 mg/kg given over 30 minutes) on systemic and renal hemodynamics in 23 patients with mild essential hypertension during 1 week of a low NaCl diet (50 mmol/d) followed by 1 week of a high NaCl diet (340 mmol/d). Patients were classified as salt sensitive (n=10) or salt resistant (n=13) based on salt-induced changes in their blood pressures. Salt loading increased renal vascular resistance but not renal plasma flow in salt-sensitive patients. The L-arginine-induced renovascular relaxation was significantly reduced by a high NaCl diet (renal vascular resistance: low NaCl -12.4 +/- 2.3% versus high NaCl -7.1 +/- 1.8%, P < .001) in salt-sensitive patients, whereas it was unchanged in salt-resistant patients. The increase in plasma cGMP in response to L-arginine was also reduced by a high NaCl diet in the salt-sensitive patients (low NaCl 49 +/- 7% versus high NaCl 36 +/- 8%, P < .05) but not in the salt-resistant patients (low NaCl 51 +/- 6% versus high NaCl 58 +/- 6%). These findings suggest that NaCl loading in salt-sensitive patients with mild essential hypertension reduces the ability of L-arginine to produce nitric oxide in the endothelium of the renal vasculature.
Higashi
Y
Y
First Department of Internal Medicine, Hiroshima University School of Medicine, Japan.
Oshima
T
T
Watanabe
M
M
Matsuura
H
H
Kajiyama
G
G
D001120:Arginine / Q000008:administration & dosage*; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000378:metabolism / Q000503:physiopathology*; D007275:Injections, Intravenous; D007668:Kidney / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism*; D012982:Sodium, Dietary / Q000008:administration & dosage*
D012982:Sodium, Dietary; D009569:Nitric Oxide; D001120:Arginine