These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Effect of aging on intestinal absorption of aromatic amino acids in vitro in the rat.
    Author: Navab F, Winter CG.
    Journal: Am J Physiol; 1988 Apr; 254(4 Pt 1):G631-6. PubMed ID: 3354681.
    Abstract:
    Whole-thickness everted jejunal rings were used to measure uptake of L-tyrosine (L-Tyr), L-phenylalanine (L-Phe), and L-tryptophan (L-Trp) in 6-, 12-, and 24-mo-old rats. The rate of uptake of all three amino acids (1 mM) was significantly reduced after 20 min of incubation in 24-mo-old compared with 6-mo-old rats. Results of influx (2 min) of 0.5-40.0 mM L-Phe and L-Trp suggested an increased affinity but decreased capacity for the transporter with age; these differences were significant for L-Trp (P less than 0.05). Respective values for apparent Kt and Vmax were the following: L-Phe 6-mo-old rats, 5.46 mM and 1.03 mumol.g-1.2 min-1; 24-mo-old rats, 2.54 mM and 0.51 mumol.g-1.2 min-1; L-Trp 6-mo-old rats, 5.09 mM and 0.38 mumol.g-1.2 min-1; 24-mo-old rats, 3.20 mM and 0.25 mumol.g-1.2 min-1. Values for 12-mo-old rats fell in between the other two age groups.
    [Abstract] [Full Text] [Related] [New Search]