Possible Interaction: Leucine and Phenylalanine

“In addition, a component of Na(+)-independent tryptophan, tyrosine and phenylalanine transport in 1-cell and 2-cell conceptuses and in blastocysts resisted inhibition by L-leucine.”

“Brain concentrations of tyrosine, phenylalanine and tryptophan were significantly reduced in animals receiving supplements of leucine for two and six weeks.”

“The combination of L-phenylalanine and L-leucine will improve the sensitivity (92.3%) and specificity (91.7%) for early diagnosis of OSCC.”

“When a large dose of phenylalanine or threonine was administered, incorporation of the tracer leucine was significantly increased (from 0.036 to 0.”

“Relationships were determined between the labeling of leucine and phenylalanine at the intracellular site of protein synthesis in the pancreas and labeling of plasma leucine, its keto acid, alpha-ketoisocaproate (KIC), and phenylalanine.”

“Plasma concentrations of essential amino acids, including threonine, methionine, isoleucine, valine, tyrosine, and phenylalanine were significantly decreased by leucine infusion.”

“According to arteriovenous differences across the leg, the net balance of phenylalanine , valine, and lysine shifted toward greater retention during leucine infusion, whereas alanine balance did not change.”

“ Leucine infusion decreased plasma concentrations of several amino acids and decreased whole body valine flux and valine oxidation (using L-[1-13C]valine as a tracer) and phenylalanine flux (using [2H5]-phenylalanine as a tracer).”

“Endothelial cell transport of L‐leucine was markedly inhibited during perfusion with 1 mM‐BCH (beta‐2‐aminobicyclo‐(2,2,1)‐heptane‐2‐carboxylic acid, system L analogue), L‐leucine, D‐leucine, L‐phenylalanine , L‐methionine and L‐DOPA.”

“Administration of certain large neutral amino‐acids (valine, isoleucine, leucine–VIL ) appears to reduce phenylalanine concentrations in the cerebrospinal fluid of humans and in the brain of rats.”

“During the infusion of leucine its concentration rose four- to six-folds, while the concentrations of several other amino acids declined continually, the effect being most pronounced for isoleucine (-55% of initial value), methionine (-55%), valine (-40%), tyrosine (-35%) and phenylalanine (-35%).”