Increases in NO2-/NO3- excretion in the urine as an indicator of the release of endothelium-derived relaxing factor during elevation of blood pressure.
1. Under hormonally constant conditions, the effects of a sudden increase in blood pressure on the release of endothelium-derived relaxing factor were evaluated by measuring urinary excretion of NO2-/NO3- in rats with renal denervation. 2. Elevation of blood pressure from 136 +/- 2 to 153 +/- 3 mmHg by an aortic clamp below the renal arteries induced a significant increase in urinary excretion of NO2-/NO3- from 76.6 +/- 4.2 x 10(2) to 108.1 +/- 8.3 x 10(2) pmol min-1 g-1 kidney weight (P less than 0.05). 3. Infusion of NG-monomethyl-L-arginine (1 mg min-1 kg-1) without an aortic clamp raised mean blood pressure to a similar level; however, urinary excretion of NO2-/NO3- was decreased significantly. 4. During infusion of NG-monomethyl-L-arginine, aortic occlusion caused a significant increase in blood pressure without any changes in NO2-/NO3- excretion in the urine. 5. These results suggest that the formation of NO, an indicator of endothelium-derived relaxing factor release, was increased by mechanical pressure elevation without apparent changes in hormonal and neural factors.
Suzuki
H
H
Department of Internal Medicine, School of Medicine, Keio University, Tokyo, Japan.
Ikenaga
H
H
Hishikawa
K
K
Nakaki
T
T
Kato
R
R
Saruta
T
T
D000818:Animals; D001013:Aorta, Thoracic; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001794:Blood Pressure / Q000502:physiology*; D003250:Constriction; D008297:Male; D009566:Nitrates / Q000652:urine*; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009573:Nitrites / Q000652:urine*; D051381:Rats; D011921:Rats, Inbred WKY; D013997:Time Factors; D019323:omega-N-Methylarginine
D009566:Nitrates; D009573:Nitrites; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D001120:Arginine