Contribution of branched-chain amino acids to purine nucleotide cycle: a pilot study

2016 ◽  
Vol 71 (5) ◽  
pp. 587-593 ◽  
Author(s):  
F-C Tang ◽  
C-C Chan
1992 ◽  
Vol 70 (1) ◽  
pp. 132-141 ◽  
Author(s):  
T. E. Graham ◽  
D. A. MacLean

This review focuses on the ammonia and amino acid metabolic responses of active human skeletal muscle, with a particular emphasis on steady-state exercise. Ammonia production in skeletal muscle involves the purine nucleotide cycle and the amino acids glutamate, glutamine, and alanine and probably also includes the branched chain amino acids as well as aspartate. Ammonia production is greatest during prolonged, steady state exercise that requires 60–80% [Formula: see text] and is associated with glutamine and alanine metabolism. Under these circumstances it is unresolved whether the purine nucleotide cycle (AMP deamination) is active; if so, it must be cycling with no IMP accumulation. It is proposed that under these circumstances the ammonia is produced from slow twitch fibers by the deamination of the branched chain amino acids. The ammonia response can be suppressed by increasing the carbohydrate availability and this may be mediated by altering the availability of the branched chain amino acids. The fate of the ammonia released into the circulation is unresolved, but there is indirect evidence that a considerable portion may be excreted by the lung in expired air.Key words: glutamine, branched chain amino acids, glutamate dehydrogenase, purine nucleotide cycle.


Nutrients ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 95
Author(s):  
Imran Ramzan ◽  
Moira Taylor ◽  
Beth Phillips ◽  
Daniel Wilkinson ◽  
Kenneth Smith ◽  
...  

Elevated circulating branched-chain amino acids (BCAAs; isoleucine, leucine, and valine) are associated with obesity and type 2 diabetes (T2D). Reducing circulatory BCAAs by dietary restriction was suggested to mitigate these risks in rodent models, but this is a challenging paradigm to deliver in humans. We aimed to design and assess the feasibility of a diet aimed at reducing circulating BCAA concentrations in humans, while maintaining energy balance and overall energy/protein intake. Twelve healthy individuals were assigned to either a 7-day BCAA-restricted diet or a 7-day control diet. Diets were iso-nitrogenous and iso-caloric, with only BCAA levels differing between the two. The BCAA-restricted diet significantly reduced circulating BCAA concentrations by ~50% i.e., baseline 437 ± 60 to 217 ± 40 µmol/L (p < 0.005). Individually, both valine (245 ± 33 to 105 ± 23 µmol/L; p < 0.0001), and leucine (130 ± 20 to 75 ± 13 µmol/L; p < 0.05), decreased significantly in response to the BCAA-restricted diet. The BCAA-restricted diet marginally lowered Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) levels: baseline 1.5 ± 0.2 to 1.0 ± 0.1; (p = 0.096). We successfully lowered circulating BCAAs by 50% while maintaining iso-nitrogenous, iso-caloric dietary intakes, and while meeting the recommended daily allowances (RDA) for protein requirements. The present pilot study represents a novel dietary means by which to reduce BCAA, and as such, provides a blueprint for a potential dietary therapeutic in obesity/diabetes.


2010 ◽  
Vol 24 (S1) ◽  
Author(s):  
Sarah Everman ◽  
Lawrence J Mandarino ◽  
Guilherme M Puga ◽  
Christian Meyer ◽  
Christos S Katsanos

2009 ◽  
Vol 24 (10) ◽  
pp. 1268-1272 ◽  
Author(s):  
Athanasios Evangeliou ◽  
Martha Spilioti ◽  
Vai Doulioglou ◽  
Panagiota Kalaidopoulou ◽  
Anestis Ilias ◽  
...  

2018 ◽  
Vol 88 (1-2) ◽  
pp. 80-89 ◽  
Author(s):  
Zahra Shakibay Novin ◽  
Saeed Ghavamzadeh ◽  
Alireza Mehdizadeh

Abstract. Branched chain amino acids (BCAA), with vitamin B6 have been reported to improve fat metabolism and muscle synthesis. We hypothesized that supplementation with BCAA and vitamin B6 would result in more weight loss and improve body composition and blood markers related to cardiovascular diseases. Our aim was to determine whether the mentioned supplementation would affect weight loss, body composition, and cardiovascular risk factors during weight loss intervention. To this end, we performed a placebo-controlled randomized clinical trial in 42 overweight and obese women (BMI = 25–34.9 kg/m2). Taking a four-week moderate deficit calorie diet (–500 kcal/day), participants were randomized to receive BCAA (6 g/day) with vitamin B6 (40 mg/day) or placebo. Body composition variables measured with the use of bioelectrical impedance analysis, homeostatic model assessment, and plasma insulin, Low density lipoprotein, High density lipoprotein, Total Cholesterol, Triglyceride, and fasting blood sugar were measured. The result indicated that, weight loss was not significantly affected by BCAA and vitamin B6 supplementation (–2.43 ± 1.02 kg) or placebo (–1.64 ± 1.48 kg). However, significant time × treatment interactions in waist to hip ratio (P = 0.005), left leg lean (P = 0.004) and right leg lean (P = 0.023) were observed. Overall, supplementation with BCAA and vitamin B6 could preserve legs lean and also attenuated waist to hip ratio.


2007 ◽  
Vol 40 (05) ◽  
Author(s):  
AH Neuhaus ◽  
TE Goldberg ◽  
Y Hassoun ◽  
JA Bates ◽  
KW Nassauer ◽  
...  

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