Method(s): LC-MS/MS (1).
What is homoarginine?
L-Homoarginine is a naturally occurring, non-proteinogenic, guanidinated, cationic amino acid. It is formed in the liver in a reaction catalyzed by L-arginine:glycine amidinotransferase (AGAT) when transferring the amidino group from arginine to lysine. It is an alternative substrate for nitric oxide (NO) synthase, increases the availability of NO and thereby affects endothelial function. Homoarginine may exert further actions that are relevant to cardiovascular health, including inhibition of platelet aggregation and stimulation of insulin secretion. Recent studies demonstrate that low serum homoarginine is a strong predictor of cardiovascular mortality (2).
Performance of the assay
Lower limit of detection (LOD): 0.10 µmol/L.
Within-day CV: 6-7 %; between-day CV: 5-8 %.
Assessment of endothelial function and cardiovascular risk.
Specimen, collection and processing
Matrix: EDTA plasma and serum.
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.
Transportation; for general instruction on transportation, click here.
Frozen, on dry ice.
Reported values, interpretation
Reported values: 2-6 µmol/L
Intraclass correlation coefficient (ICC): 0.65.
1. Midttun, O., Kvalheim, G., and Ueland, P.M. (2013). High-throughput, low-volume, multianalyte quantification of plasma metabolites related to one-carbon metabolism using HPLC-MS/MS. Anal Bioanal Chem 405, 2009-017.
2. Atzler, D., Schwedhelm, E., and Choe, C.U. (2015). L-Homoarginine and cardiovascular disease. Curr Opin Clin Nutr Metab Care 18, 83-88.