Citrulline possesses a highly specific metabolism that bypasses splanchnic extraction because it is not used by the intestine or taken up by the liver. The administration of citrulline may be used to deliver available nitrogen for protein homeostasis in peripheral tissues and as an arginine precursor synthesized de novo in the kidneys and endothelial and immune cells. Fresh research has shown t...

BACKGROUND Many human studies report that nitric oxide (NO) improves sport performance. This is because NO is a potential modulator of blood flow, muscle energy metabolism, and mitochondrial respiration during exercise. L-Citrulline is an amino acid present in the body and is a potent endogenous precursor of L-arginine, which is a substrate for NO synthase. Here, we investigated the effect of o...

1. The kinetics, specificity, pH-and Na +-dependency of L-citrulline transport were examined-2-in unstimulated and lipopolysaccharide (LPS) activated murine macrophage J774 cells. The dependency of nitric oxide production on extracellular arginine or citrulline was investigated in cells activated with LPS (1 μg ml-1) for 24 h. 2. In unstimulated J774 cells transport of citrulline was saturable ...

Endogenous nitric oxide synthase (eNOS) inhibitor asymmetric dimethylarginine (ADMA) is a cardiovascular risk factor. We tested the hypothesis that L-citrulline may ameliorate the endothelial function altered by ADMA in porcine coronary artery (PCA). Myograph study for vasorelaxation, electrochemical measurement for NO, RT-PCR, and Western blot analysis for expression of eNOS, argininosuccinate...

A characteristic consequence of a biotin deficiency in animals is a decreased ability to fix C402 into various tissue components including the amino acid arginine (1). Carbon dioxide is incorporated into arginine as a result of the conversion of ornithine to citrulline in the Krebs-Henseleit urea cycle (2). The methods developed by Cohen and Hayano (3, 4) for the synthesis of citrulline from or...

Citrulline (CIT), a non-protein amino acid in circulating blood, is almost exclusively contained in the enterocytes of small bowel mucosa and may represent a reliable marker of functioning enterocyte mass. The aim of this study was to evaluate the clinical utility of measuring serum citrulline levels in a group of patients affected by coeliac disease (CD). Fifty healthy volunteers, 21 patients ...

We investigated the composition of free amino acids in walnut (Juglans regia L.) seeds (embryo and cotyledons). We also examined xylem transport of free amino acids in young seedlings grown in the absence of external nutrients. A relatively high concentration of free alanine was found in seed tissue, whereas a relatively high concentration of citrulline was detected in young seedlings. Citrulli...

THE carbamido-acid citrulline, isolated by Koga & Odake in 1914 from the water melon, attracted no general attention until Wada [1930] established its constitution as cx-amino-&-carbamidovaleric acid, and showed [1933, 1] that it also occurred among the products of the tryptic digestion of caseinogen. The importance of the acid in nitrogen metabolism was revealed when Krebs & Henseleit [1932] d...

The study of the regulation of the arginine biosynthesis in Chlumydomonas [ 1, 21 is complicated by the degradation of arginine. As we reported earlier [3], the first enzyme of the catabolic pathway is arginine deiminase (L-arginine imino hydrolase, EC 3.5.3.6.). This enzyme causes the breakdown of arginine to citrulline and ammonia. Citrulline is then further degraded. Two pathways for the deg...

Arginine has vasodilatory effects, via its conversion by NO synthase into NO, and immunomodulatory actions which play important roles in sepsis. Protein breakdown affects arginine availability and the release of asymmetric dimethylarginine, an inhibitor of NO synthase, may therefore affect NO synthesis in patients with sepsis. The objective of the present study was to investigate whole-body in ...