TY - JOUR T1 - Changes in Salivary Amino Acid Composition During Aging JF - In Vivo JO - In Vivo SP - 853 LP - 856 VL - 24 IS - 6 AU - SHOJI TANAKA AU - MAMORU MACHINO AU - SAYOKO AKITA AU - YOSHIKO YOKOTE AU - HIROSHI SAKAGAMI Y1 - 2010/11/01 UR - http://iv.iiarjournals.org/content/24/6/853.abstract N2 - Background: It has been suggested that the features of saliva reflect the physiological and psychological state of primates as well as subprimates, however, studies revealing the relationship between aging and the concentrations of salivary amino acids are limited. In order to better understand their physiological role, age-related changes of salivary amino acids were investigated. Materials and Methods: Forty-five participants including 5 children [6.60±1.67 (5-9) years old], 20 adults [46.55±14.68 (23-64) years old), and 20 senior citizens [71.60±4.27 (66-82) years old] took part in this study. Whole saliva (one sample per each person) was collected in the daytime (10:00-11:00 or 14:00-15:00). Salivary amino acids were recovered after deproteinization with 5% trichloroacetic acid and determined by an amino acid analyzer. Results: Glycine was the most abundant amino acid in the saliva. Glycine and lysine levels increased significantly (p<0.05) with aging, regardless of gender difference. When the glycine and lysine levels were plotted, much higher correlation (p<0.001) was observed. On the other hand, there was no significant correlation between the salivary concentration of glutamic acid or histidine and age. Conclusion: Salivary amino acid levels may be regarded as markers of aging. ER -