title: Plasma amino acid concentrations in healthy elderly men and women.
abstract: Postabsorptive plasma concentrations of the large neutral amino acids (LNAAs) were measured in 74 elderly (age 71 +/- 8 y) and 138 young (age 26 +/- 5 y) healthy subjects. Plasma concentrations of valine, leucine, and isoleucine were significantly lower in young females than in young males. This gender-related difference was not observed among elderly subjects because aging was associated with a significant rise in plasma LNAAs in females but not in males. Multiple-regression analysis of plasma amino acid concentrations from female subjects revealed a significant and positive effect of age on plasma valine, leucine, isoleucine, phenylalanine, and tyrosine but not on plasma tryptophan or methionine. Tryptophan was the only amino acid to exhibit a significant response to age in males, consisting of a 14% decline in the elderly subjects. Percentile ranges are presented for young and elderly females and males for each of the amino acids.
authors.affiliation: Clinical Research Center, Massachusetts Institute of Technology, Cambridge.
authors.forename: B
authors.initials: B
authors.lastname: Caballero
authors.forename: R E
authors.initials: RE
authors.lastname: Gleason
authors.forename: R J
authors.initials: RJ
authors.lastname: Wurtman
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood*; D000596:Amino Acids / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012044:Regression Analysis; D012737:Sex Factors
chemical_list: D000596:Amino Acids