title: Importance of sites of tracer administration and blood sampling in relation to leucine metabolism. Practical considerations.
abstract: For the same infusion site of L-[1-14C]leucine, sampling downstream of arterial blood underestimates leucine turnover, whereas sampling of venous blood overestimates turnover. Further, the lungs release a small but consistent amount of leucine into the blood. Unlabelled leucine also is produced by the portal-drained viscera, and some is removed immediately by the liver. These sources of leucine should thus be considered in turnover calculations.
mesh_terms: D000818:Animals; D001158:Arteries; D001800:Blood Specimen Collection; D002250:Carbon Radioisotopes; D007930:Leucine / Q000097:blood / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D012756:Sheep; D014680:Veins
chemical_list: D002250:Carbon Radioisotopes; D007930:Leucine