Training and muscle ammonia and amino acid metabolism in humans during prolonged exercise
Research output: Contribution to journal › Journal article › Research › peer-review
Standard
Training and muscle ammonia and amino acid metabolism in humans during prolonged exercise. / Graham, T E; Turcotte, L P; Kiens, Bente; Richter, Erik A.
In: Journal of Applied Physiology, Vol. 78, No. 2, 1995, p. 725-735.Research output: Contribution to journal › Journal article › Research › peer-review
Harvard
APA
Vancouver
Author
Bibtex
}
RIS
TY - JOUR
T1 - Training and muscle ammonia and amino acid metabolism in humans during prolonged exercise
AU - Graham, T E
AU - Turcotte, L P
AU - Kiens, Bente
AU - Richter, Erik A.
PY - 1995
Y1 - 1995
N2 - We studied the responses of NH3 and amino acids (AA) to prolonged exercise (3 h) in trained (Tr; n = 6) and untrained (Utr; n = 6) men. Each subject exercised the knee extensor muscles of one leg at 60% of maximum capacity. Thigh blood flow and femoral arteriovenous differences (0, 30, 60, 120, 150, and 180 min) as well as muscle biopsies (0, 120, and 180 min) were taken for NH3 and AA measurements. In both groups, muscle Glu decreased (P < 0.05) and Asp increased (P < 0.05), but the intramuscular AA pool, including the essential AA, remained constant despite a total AA efflux of 22.4 +/- 8.3 and 24.4 +/- 6.8 mmol/kg wet wt in Tr and Utr, respectively. Tr had greater (P < 0.05) muscle Tau, Phe, Ala, and Glu. Both groups had a large Glu uptake and effluxes of NH3, Gln, and Ala as well as essential AA. The latter implies that there was a net protein catabolism. The efflux of NH3 and Gln was much greater than that expected from AMP deamination, suggesting that deamination of AA was occurring. Many of the AA responses use Glu, and Tr maintained the intramuscular Glu pool at a higher concentration (P < 0.05), implying that they derived more Glu from protein catabolism and/or AA transaminations. Under these conditions, prolonged dynamic knee extensor exercise is associated with a large release of alpha-amino moieties both as NH3 and as Gln as well as a net protein catabolism; these responses are similar in Tr and Utr.
AB - We studied the responses of NH3 and amino acids (AA) to prolonged exercise (3 h) in trained (Tr; n = 6) and untrained (Utr; n = 6) men. Each subject exercised the knee extensor muscles of one leg at 60% of maximum capacity. Thigh blood flow and femoral arteriovenous differences (0, 30, 60, 120, 150, and 180 min) as well as muscle biopsies (0, 120, and 180 min) were taken for NH3 and AA measurements. In both groups, muscle Glu decreased (P < 0.05) and Asp increased (P < 0.05), but the intramuscular AA pool, including the essential AA, remained constant despite a total AA efflux of 22.4 +/- 8.3 and 24.4 +/- 6.8 mmol/kg wet wt in Tr and Utr, respectively. Tr had greater (P < 0.05) muscle Tau, Phe, Ala, and Glu. Both groups had a large Glu uptake and effluxes of NH3, Gln, and Ala as well as essential AA. The latter implies that there was a net protein catabolism. The efflux of NH3 and Gln was much greater than that expected from AMP deamination, suggesting that deamination of AA was occurring. Many of the AA responses use Glu, and Tr maintained the intramuscular Glu pool at a higher concentration (P < 0.05), implying that they derived more Glu from protein catabolism and/or AA transaminations. Under these conditions, prolonged dynamic knee extensor exercise is associated with a large release of alpha-amino moieties both as NH3 and as Gln as well as a net protein catabolism; these responses are similar in Tr and Utr.
KW - Adult
KW - Amino Acids
KW - Ammonia
KW - Blood Glucose
KW - Blood Pressure
KW - Ergometry
KW - Exercise
KW - Humans
KW - Lipids
KW - Male
KW - Muscle, Skeletal
KW - Physical Education and Training
KW - Regional Blood Flow
KW - Thigh
M3 - Journal article
C2 - 7759446
VL - 78
SP - 725
EP - 735
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
SN - 8750-7587
IS - 2
ER -
ID: 154754985