Amino acid metabolism in muscle and in the whole body of man before and after ingestion of a single mixed meal.
Whole-body energy expenditure, protein oxidation, and exchange of amino acids, glutathione, and other metabolites across forearm muscle were assessed before and for 4 h after ingestion of a single meal containing 3274 kJ (783 kcal) and 25.5 g protein (4.08 g nitrogen). The study 1) demonstrates the dominance of glutamine over all other amino acids in carrying N out of skeletal muscle (1.33 mumol.L muscle-1.min-1 between 0 and 4 h--equivalent to 71% of the amino acid release or 82% of the amino acid N release); 2) suggests that glucose-alanine recycling between muscle and liver is not increased in the postprandial period despite the large uptake of glucose by muscle; 3) provides no support for the hypothesis that a substantial amount of N is exchanged between blood and muscle in the form of glutathione; and 4) considers the overall quantitative importance of amino acid oxidation in the whole body and the accompanying exchange of amino acids in skeletal muscle.
Elia
M
M
Dunn Clinical Nutrition Centre, Cambridge.
Folmer
P
P
Schlatmann
A
A
Goren
A
A
Austin
S
S
D000328:Adult; D000409:Alanine / Q000378:metabolism; D000596:Amino Acids / Q000378:metabolism*; D003404:Creatinine / Q000652:urine; D004044:Dietary Proteins / Q000008:administration & dosage; D002149:Energy Intake; D004734:Energy Metabolism; D005502:Food; D005947:Glucose / Q000378:metabolism; D005973:Glutamine / Q000378:metabolism; D005978:Glutathione / Q000097:blood; D006801:Humans; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D008297:Male; D009132:Muscles / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism; D010101:Oxygen Consumption
D000596:Amino Acids; D004044:Dietary Proteins; D005973:Glutamine; D003404:Creatinine; D005978:Glutathione; D005947:Glucose; D009584:Nitrogen; D000409:Alanine