Specificity of the Acute Tryptophan and Tyrosine plus Phenylalanine Depletion and Loading Tests Part II: Normalisation of the Tryptophan and the Tyrosine Plus Phenylalanine to Competing Amino Acid Ratios in a New Control Formulation:

International Journal of Tryptophan Research

Abdulla A.-B.Badawy¹ 

关键词: acute tryptophan depletion;    loading;    acute tyrosine depletion test;    amino acid formulations;    branched-chain amino acids;    catecholamines;    competing amino acids;    dopamine;    isoleucine;    leucine;    noradrenaline;    phenylalanine;    tryptophan;    tyrosine;    valine;   

DOI  :  10.4137/IJTR.S5169

学科分类：生物科学（综合）

来源: Sage Journals

【 摘 要 】

Current formulations for acute tryptophan (Trp) or tyrosine (Tyr) plus phenylalanine (Phe) depletion and loading cause undesirable decreases in ratios of Trp or Tyr + Phe to competing amino acids (CAA), thus undermining the specificities of these tests. Branched-chain amino acids (BCAA) cause these unintended decreases, and lowering their content in a new balanced control formulation in the present study led to normalization of all ratios. Four groups (n = 12 each) of adults each received one of four 50 g control formulations, with 0% (traditional), 20%, 30%, or 40% less of the BCAA. The free and total [Trp]/[CAA] and [Phe + Tyr]/[BCAA+ Trp] ratios all decreased significantly during the first 5 h following the traditional formulation, but were fully normalized by the formulation containing 40% less of the BCAA. We recommend the latter as a balanced control formulation and propose adjustments in the depletion and loading formulations to enhance their specificities for 5-HT and the catecholamines.

【 授权许可】

CC BY