BACKGROUND Assessment of a quantifiable small intestinal function test is cumbersome. Fasting citrulline concentrations have been proposed as a measure of enterocyte function and elaborated into a citrulline generation test (CGT), which is applicable only when glutamine is administered orally. CGT is an oral test, limiting its use, for example, in critically ill patients. OBJECTIVE Assessment...

Of late, there has been a major increase in the marketing of sport nutraceuticals claiming to augment exercise performance and recovery due to their ability to increase nitric oxide (NO) release. NO is a labile molecule that is known to play a major role in regulating vasodilation, blood flow, platelet adhesion, immune system function, and mitochondrial respiration. Endogenous NO synthesis is c...

Although glutamine is considered the main precursor for citrulline synthesis, the current literature does not differentiate between the contribution of glutamine carbon skeleton vs. nonspecific nitrogen (i.e., ammonia) and carbon derived from glutamine oxidation. To elucidate the role of glutamine and nonspecific nitrogen in the synthesis of citrulline, l-[2-(15)N]- and l-[5-(15)N]glutamine and...

Activation, recruitment, and effector function of T lymphocytes are essential for control of mycobacterial infection. These processes are tightly regulated in T cells by the availability of l-arginine within the microenvironment. In turn, mycobacterial infection dampens T cell responsiveness through arginase induction in myeloid cells, promoting sequestration of l-arginine within the local mili...

Nitric oxide synthase (NOS) was evidenced in mature mouse spermatozoa by means of biochemical techniques and Western blot. During 120 min of incubation, 10(7) spermatozoa synthesized 7 +/- 2 pmol of L-[14C]citrulline. Besides, L-citrulline formation depended on the incubation time and on the concentration of L-arginine present in the incubation medium. Different concentrations of N(G)-nitro-L-a...

BACKGROUND To evaluate the effect of the amino acids L-arginine and citrulline on endothelial function in patients in stable diastolic and right heart failure using photoplethysmography. METHODS Thirty patients from the Heart Failure Clinic of the Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán" underwent photoplethysmography using the hyperemia technique. Index finger fl...

Weakly electric fish produce electric organ discharges (EODs) used for electrolocation and communication. In the brown ghost knifefish, Apteronotus leptorhynchus, several neuron types in brain regions that control the EOD or process electrosensory information express nitric oxide synthase (NOS). The present study used immunoreactivity for L-citrulline, a byproduct of the production of nitric ox...

L-Arginine (Arg) has been widely used due to its functional properties as a substrate for nitric oxide (NO) generation. However, L-citrulline (CIT), whose main natural source is watermelon, non-essential amino acid but which important health potential. This review provides comprehensive approach different studies of the endogenous synthesis CIT, metabolism, pharmacokinetics, and pharmacodynamic...

BACKGROUND The utility of L-arginine and L-citrulline in treatment of arterial hypertension by increasing vascular oxide nitric availability has been demonstrated. Photoplethysmography, a simple and low-cost optical technique, makes it possible to assess vascular function and to detect changes in blood flow, pulse and swelling of the microvascular tissular space. The aim of the study was to eva...

Our recent publication showed that pharmacological blockade of arginases confers kidney protection in diabetic nephropathy via a nitric oxide (NO) synthase (NOS)3-dependent mechanism. Arginase competes with endothelial NOS (eNOS) for the common substrate L-arginine. Lack of L-arginine results in reduced NO production and eNOS uncoupling, which lead to endothelial dysfunction. Therefore, we hypo...