title: Free amino acids in plasma, red blood cells, polymorphonuclear leukocytes, and muscle in normal and uraemic children.
abstract: BACKGROUND
  The aims of this study were to investigate free amino acid (AA) concentrations in plasma, red blood cells (RBC), polymorphonuclear granulocytes (PMN), and muscle, sampled at the same time, in normal and uraemic children.
  
  
  METHODS
  Twelve apparently well-nourished chronically uraemic children (five females) aged a mean of 9.4+/-4.8 (range 1.7--17.7) years and 13 age-matched normal children were studied. Venous blood and muscle samples for AA analyses were taken simultaneously after an overnight fast.
  
  
  RESULTS
  The intracellular AA patterns in the three cellular compartments were qualitatively similar, but the absolute intracellular concentrations were higher in muscle than in PMN, which had higher values than in RBC. The AA patterns in plasma, RBC, PMN, and muscle in the uraemic children have many similarities; typical features being low branched-chain AA (BCAA), tyrosine, and serine concentrations and variably high concentrations of some non-essential AA. Among the individual AA, there were only few correlations between their concentrations in the three cell compartments.
  
  
  CONCLUSIONS
  The lack of correlation between the concentrations in RBC, PMN, and muscle for most of the AA indicates that there is no close association in the same subject between individual free AA concentrations in various types of cells, presumably because of differences in metabolism and function. Consequently, one should be cautious in assuming that AA concentrations, determined in RBC or PMN, reflect the concentrations in muscle cells. Therefore, these preliminary observations do not support the hypothesis that RBC and PMN AA analysis can be considered as a suitable alternative to muscle AA determination.
authors.affiliation: Department of Nephrology, Istituto G. Gaslini, Genova, Italy. nefroigg@tin.it
authors.forename: Alberto
authors.initials: A
authors.lastname: Canepa
authors.forename: José Carolino Divino
authors.initials: JC
authors.lastname: Filho
authors.forename: Alberto
authors.initials: A
authors.lastname: Gutierrez
authors.forename: Alba
authors.initials: A
authors.lastname: Carrea
authors.forename: Ann-Marie
authors.initials: AM
authors.lastname: Forsberg
authors.forename: Eva
authors.initials: E
authors.lastname: Nilsson
authors.forename: Enrico
authors.initials: E
authors.lastname: Verrina
authors.forename: Francesco
authors.initials: F
authors.lastname: Perfumo
authors.forename: Jonas
authors.initials: J
authors.lastname: Bergström
mesh_terms: D000293:Adolescent; D000596:Amino Acids / Q000097:blood* / Q000378:metabolism*; D000601:Amino Acids, Essential / Q000097:blood / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009132:Muscles / Q000378:metabolism*; D009504:Neutrophils / Q000378:metabolism; D014511:Uremia / Q000097:blood* / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D000601:Amino Acids, Essential