Dietary Protein or Arginine Deficiency Impairs Constitutive and Inducible Nitric Oxide Synthesis by Young Rats

Abstract

Effects of dietary protein or arginine deficiency on constitutive and lipopolysaccharide (LPS)-induced nitric oxide (NO) synthesis were determined in young rats by quantifying urinary nitrate excretion. In Experiment 1, 30-d-old rats (n = 16) were divided randomly into two groups (n = 8/group) and pair-fed on the basis of body weight semipurified isocaloric diets containing 20 or 5% casein. In Experiment 2, 30-d-old rats (n = 24) were divided randomly into three groups (n = 8) and pair-fed on the basis of body weight purified isonitrogenous and isocaloric diets (composed of amino acids) containing 0.0, 0.3 or 1.0% L-arginine. In both experiments, daily collection of urine was initiated 10 d after the start of pair-feeding. On d 17 after the pair-feeding was initiated, LPS (1 mg/kg body wt) was injected intraperitoneally into rats, and urine was collected daily for an additional 7 d. In Experiments 3 and 4, activities of constitutive and inducible NO synthases were measured in macrophages and various tissues from protein- or arginine-deficient rats (n = 6). Body weight was lower in rats fed the 5% casein diet or the 0.0 and 0.3% arginine diets than in those fed 20% casein or 1% arginine, respectively. Dietary protein or arginine deficiency decreased serum concentrations of arginine and urinary nitrate excretion before and after LPS treatment, indicating impaired constitutive and inducible NO synthesis. Protein malnutrition reduced constitutive and inducible NO synthase activities in brain, heart, jejunum, lung, skeletal muscle and spleen, and inducible NO synthase activity in macrophages. Because NO is a mediator of the immune response and is the endothelium-dependent relaxing factor, impaired NO synthesis may help explain immunodeficiency and cardiovascular dysfunction in protein- or arginine-deficient subjects.

Arginine synthesis is regulated by dietary arginine intake in the enterally fed neonatal piglet

“…In rats, Wu et al (34) observed a reduction in NO synthesis by constitutive NO synthase and inducible NO synthase during arginine deficiency, although the magnitude of the response was smaller in the rats than in the present study. To the authors' knowledge, no comparable studies of the influence of dietary arginine on NO synthesis exist in healthy neonates.…”

Antihypertensive Effect of Quercetin in Rats Fed with a High-Fat High-Sucrose Diet

“…The total nitrate and nitrite concentrations in the urine and plasma were measured by reacting with the Greiss reagent according to the procedure described by Wu et al 22) The NO metabolites excreted in the urine are expressed as total nitrate and nitrite per creatinine in the urine. Creatinine excreted in the urine was determined by using a commercial diagnostic kit (creatininetest) from Wako Pure Chemicals.…”

Variation in L-arginine intake follow demographics and lifestyle factors that may impact cardiovascular disease risk

“…Recent studies suggest that supplemental L-arginine may be helpful in preventing harmful oxidation and reversing endothelial dysfunction [6]. In addition, supplementation with Larginine may reverse the endothelial dysfunction associated with hypercholesterolemia, smoking, and hypertension [7][8][9][10][11][12][13][14]. Some of L-arginine's antioxidant and anti-inflammatory effects are independent of NO production [15,16].…”