Intra- and Extracellular Amino Acid Concentrations in Ammonium-Infused Rats. Evidence that Hyperammonemia Reduces BCAA Levels

2015 ◽  
pp. 552-554
Author(s):  
H. Leweling ◽  
E. Holm ◽  
U. Staedt ◽  
J.-P. Striebel ◽  
A. Tschepe
Keyword(s):  
Amino Acid ◽  
Amino Acid Concentrations ◽  
Extracellular Amino Acid

An intragastric amino acid mixture influences extracellular amino acid profiles in the lateral hypothalamic area of freely moving rats

1999 ◽  
Vol 77 (11) ◽  
pp. 827-834 ◽  
Author(s):  
Yang-Ho Choi ◽  
Nancy Chang ◽  
G Harvey Anderson
Keyword(s):  
Amino Acid ◽  
Amino Acid Mixture ◽  
Lateral Hypothalamic Area ◽  
Acid Mixture ◽  
Hypothalamic Area ◽  
Lateral Hypothalamic ◽  
Freely Moving Rats ◽  
Freely Moving ◽  
Amino Acid Concentrations ◽  
Extracellular Amino Acid

We tested the effect of equicaloric loads of glucose (0.89 g) or a balanced amino acid mixture (0.85 g) on extracellular amino acid concentrations in the brains of freely moving rats. At 15:30 hours, the microdialysis probe was inserted into the lateral hypothalamic area of ambulatory rats, and food and water were removed. Dialysates were collected every 20 min from 1 h prior to gavage (18:00 hours) and until 3 h after the gavage. Amino acid concentrations in the dialysate were determined by reverse-phase HPLC. Following the amino acid gavage, extracellular amino acid concentrations significantly increased from baseline for alanine, isoleucine, leucine, methionine, threonine, tyrosine, and valine. Those elevations occurred within 20-40 min following the amino acid load, and lasted up to 100 min. After the glucose and water treatments, amino acid concentrations were either not affected or gradually diminished from baseline. We conclude that extracellular amino acid concentration in the lateral hypothalamus is influenced by the composition of food consumed.Key words: blood-brain barrier, food intake, glucose, microdialysis, protein.

Neutral amino acid transport pathways in uptake of L-thyroxine by Ehrlich ascites cells

1975 ◽  
Vol 229 (1) ◽  
pp. 172-177 ◽  
Author(s):  
LK Stitzer ◽  
JA Jacquez
Keyword(s):  
Amino Acid ◽  
Amino Acid Transport ◽  
Extracellular Fluid ◽  
Neutral Amino Acid ◽  
Acid Transport ◽  
Transport Pathways ◽  
Ehrlich Ascites ◽  
Ehrlich Ascites Cells ◽  
Amino Acid Concentrations ◽  
Extracellular Amino Acid

Neutral amino acid pathways were investigated as possible mediators of L-thyroxine (T4) entry into ascites cells. 14C-Labeled T4, alpha-aminoisobutyric acid (AIB), L-phenylalanine (Phe), and cycloleucine (cLeu) uptakes were measured at initial extracellular amino acid concentrations of 1 muM in a modified Krebs-Ringer phosphate buffer, pH 7.4. T4 uptake was markedly slower than that of AIB, Phe, or cLeu over a 25-min period. T4 uptake was neither competitively stimulated nor inhibited by either AIB or Phe when these latter amino acids were varied over the concentration range 1.0 x 10(-6) to 1.0 x 10(-2) M. Preloading cells with 30 mM L-methionine did not enhance the uptake of T4. TJ efflux from preloaded cells was not affected by either AIB or Phe in the extracellular fluid (ECF). The uptakes of AIB, Phe, and cLeu were markedly altered by replacement of ECF Na+ with choline+, whereas T4 uptake was unchanged. It was concluded that neural amino acid transport pathways (specifically A, L, ASC, and beta) do not participate in the transmembrane transfer of L-thyroxine into Ehrlich ascites cells.

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