The basic amino acid arginine serves as an essential precursor for the synthesis of biological important molecules including ornithine, proline, polyamines, creatine, glutamate, homoarginine, methylated arginines (ADMA and SDMA) and nitric oxide (NO) (2). NO is an important ubiquitous gaseous signalling molecule involved in vasodilation, platelet aggregation, inflammation and neurotransmission. Although NO synthesis accounts for a small fraction of total arginine utilization, there is a dose-response-relationship between NO synthesis and arginine intake, a relationship that is expected to be strong in subjects with low basal NO synthesis, as in many pathological conditions. The arginine-NO system has been studies in variety of conditions, including cardiovascular disease, hypertension, preeclampsia, diabetes, insulin resistance and obesity.
Should be measured together with asymmetric dimethylarginine (and homoarginine) for the assessment of endothelial function and cardiovascular risk.
Patient/subject: Prandial status affects concentration, which increases after arginine intake.
Matrix: EDTA plasma and serum. Arginine decreases (up to 70%) in samples with hemolysis.
Volume: Minimum volume is 50 µL, but 200 µL is optimal and allows reanalysis.
Preparation and stability: The blood sample must be centrifuged and the plasma/serum fraction put on ice, and frozen.
Reported values: 10-100 µmol/L
Intraclass correlation coefficient (ICC): 0.53.