Effects of oral supplementation with glutamine and alanyl-glutamine on glutamine, glutamate, and glutathione status in trained rats and subjected to long-duration exercise.
OBJECTIVE
We investigated the effect of supplementation with the dipeptide L-alanyl-L-glutamine (DIP) and a solution containing L-glutamine and L-alanine, both in the free form, on the plasma and tissue concentrations of glutamine, glutamate, and glutathione (GSH) in rats subjected to long-duration exercise.


METHODS
Rats were subjected to sessions of swim training. Twenty-one days before sacrifice, the animals were supplemented with DIP (1.5 g/kg, n = 6), a solution of free L-glutamine (1 g/kg) and free L-alanine (0.61 g/kg; GLN + ALA, n = 6), or water (CON, n = 6). Animals were sacrificed before (TR, n = 6) or after (LD, n = 6) long-duration exercise. Plasma concentrations of glutamine, glutamate, glucose, and ammonia and liver and muscle concentrations of glutamine, glutamate, and reduced and oxidized (GSSG) GSH were measured.


RESULTS
Higher concentrations of plasma glutamine were found in the DIP-TR and GLN + ALA-TR groups. The CON-LD group showed hyperammonemia, whereas the DIP-LD and GLN + ALA-LD groups exhibited lower concentrations of ammonia. Higher concentrations of glutamine, glutamate, and GSH/GSSG in the soleus muscle and GSH and GSH/GSSG in the liver were observed in the DIP-TR and GLN + ALA-TR groups. The DIP-LD and GLN + ALA-LD groups exhibited higher concentrations of GSH and GSH/GSSG in the soleus muscle and liver compared with the CON-LD group.


CONCLUSIONS
Chronic oral administration of DIP and free GLN + ALA before long-duration exercise represents an effective source of glutamine and glutamate, which may increase muscle and liver stores of GSH and improve the redox state of the cell.
Cruzat
Vinicius Fernandes
VF
Department of Food Science and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil.
Tirapegui
Julio
J
D000284:Administration, Oral; D000409:Alanine / Q000008:administration & dosage / Q000494:pharmacology; D000641:Ammonia / Q000097:blood; D000818:Animals; D019587:Dietary Supplements; D004151:Dipeptides / Q000008:administration & dosage / Q000494:pharmacology*; D018698:Glutamic Acid / Q000378:metabolism*; D005973:Glutamine / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D005978:Glutathione / Q000097:blood*; D008099:Liver / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D010805:Physical Conditioning, Animal; D051381:Rats; D017208:Rats, Wistar
D004151:Dipeptides; D005973:Glutamine; D018698:Glutamic Acid; D000641:Ammonia; D005978:Glutathione; D000409:Alanine; C054122:alanylglutamine