Developmental changes in the concentrations of glutamine and other amino acids in plasma and skeletal muscle of the Standardbred foal1

• Published in: Journal of animal science 2009-08, Vol.87 (8), p.2528-2535
• Main Authors: Manso Filho, H. C., McKeever, K. H., Gordon, M. E., Manso, H. E., Lagakos, W. S., Wu, G., Watford, M.
• Format: Article
• Language: English
• Subjects: Amino acids; Animal sciences; Horses
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/jas.2009-1845

Glutamine is concentrated within skeletal muscle, where it has been proposed to play a regulatory role in maintaining protein homeostasis. The work presented here addressed the hypothesis that glutamine would be the most abundant free α-AA in plasma and skeletal muscle in the foal during the first year of life. Glycine, however, was the most abundant free α-AA in plasma at birth and between 3 and 12 mo of age. The concentration of glutamine, the second most abundant AA at birth, increased through the first 7 d (P < 0.05) and then returned to values similar to those at birth. This resulted in glutamine being the most abundant free α-AA in plasma from 1 d through 1 mo of age. The most abundant free α-AA in skeletal muscle at birth was glutamine, but the concentration fell by more than 50% by d 15 and continued to decrease, reaching about one-third of the original values by 1 yr of age (P