@article{7e832708b1694a9f97e93aa64a91489f,
title = "Elevation of plasma tyrosine after a single oral dose of L-tyrosine",
abstract = "Plasma tyrosine concentrations in twelve normal, fasting human subjects were significantly elevated 2-8 hours after they ingested 100 mg/kg or 150 mg/kg tyrosine. Mean plasma tyrosine levels were maximal after 2 hours, rising from 69 ± 3.9 to 154 ± 9.5 nmols/ml(X ± SEM) after the 100 mg/kg dose and to 203 ± 31.5 nmols/ml after the 150 mg/kg dose (p ≤ 0.001 for both doses). The mean tyrosine ratio (defined as the ratio of plasma tyrosine concentration to the sum of the concentrations of six other neutral amino acids that compete for the same blood-brain barrier uptake system) increased from 0.10 ± 0.02 to 0.28 ± 0.04 (X ± SEM) 2 hours after the 100 mg/kg dose (p ≤ 0.001) and to 0.35 ± 0.05 2 hours after the 150 mg/kg dose (p ≤ 0.005). No side effects of orally-administered L-tyrosine were noted.",
author = "Glaeser, {Bruce S.} and Eldad Melamed and Growdon, {John H.} and Wurtman, {Richard J.}",
note = "Funding Information: Circulating tyrosine is the major physiological precursor of brain dopamine and norepinephrine (1) ; its availability to brain neurons can influence the rates at which neurons synthesize these transmitters (2,3) . Tyrosine enters the brain by an uptake system in the blood-brain barrier that is shared with other neutral amino acids (NAA) such as valine, leucine, isoleucine, phenylalanine, methionine, and tryptophan (4) . The flux of tyrosine into the brain, as well as steady-state brain tyrosine levels, generally depend on the ratio of the plasma tyrosine concentration to the 1 These studies were supported in part by grants from the National Institutes of Healt{\"u} (AM-14228) and the National Aeronautics and Space Administration (NGR-22-009-627) . Dr . Melamed is an NIH-Fogarty International Fellow (F05 TW 02579-01) . Dr . Growdon is the George Cotzias Fellow of the American Parkinson's Disease Association .",
year = "1979",
month = jul,
day = "16",
doi = "10.1016/0024-3205(79)90294-7",
language = "אנגלית",
volume = "25",
pages = "265--271",
journal = "Life Sciences",
issn = "0024-3205",
publisher = "Elsevier Inc.",
number = "3",
}