TY - JOUR
T1 - Source and amount of dietary nonspecific nitrogen in relation to whole- body leucine, phenylalanine, and tyrosine kinetics in young men
AU - Hiramatsu, T.
AU - Cortiella, J.
AU - Marchini, J. S.
AU - Chapman, T. E.
AU - Young, V. R.
PY - 1994
Y1 - 1994
N2 - We studied the effects of amount and source of nonspecific nitrogen (NSN) on the oxidation of leucine and hydroxylation of phenylalanine. In phase 1, seven adult males received for 6 d diets providing indispensable amino acid intakes to meet the 1985 FAO/WHO/UNU (FAO) requirements or our proposed requirement values (MIT). During one diet period with each diet, the NSN of the basal diets (total nitrogen intake: 107 mg N · kg-1 · d-1) was increased to a total of 160 mg N · kg-1 · d-1. On the morning of day 7, an 8-h constant intravenous tracer-infusion protocol (3-h fast; 5-h fed state) was conducted with L-[I-13C]leucine, L-[ring-2H5]phenylalanine, and L-[3,3,2H2]-tyrosine as tracers. In phase 2, six subjects were given three diets for 6 d, supplying 107 mg N · kg-1 · d-1; NSN was a mixture of dispensable amino acids in which glutamine accounted for 0%, 12.5%, and 100% of total NSN. Leucine oxidation and phenylalanine hydroxylation rates and whole-body leucine and phenylalanine balances were unaffected by addition of supplemental NSN to the diets in phase 1 or by amino acid source of NSN in phase 2. Leucine and phenylalanine balances were lower (P < 0.05) for FAO compared with MIT diets.
AB - We studied the effects of amount and source of nonspecific nitrogen (NSN) on the oxidation of leucine and hydroxylation of phenylalanine. In phase 1, seven adult males received for 6 d diets providing indispensable amino acid intakes to meet the 1985 FAO/WHO/UNU (FAO) requirements or our proposed requirement values (MIT). During one diet period with each diet, the NSN of the basal diets (total nitrogen intake: 107 mg N · kg-1 · d-1) was increased to a total of 160 mg N · kg-1 · d-1. On the morning of day 7, an 8-h constant intravenous tracer-infusion protocol (3-h fast; 5-h fed state) was conducted with L-[I-13C]leucine, L-[ring-2H5]phenylalanine, and L-[3,3,2H2]-tyrosine as tracers. In phase 2, six subjects were given three diets for 6 d, supplying 107 mg N · kg-1 · d-1; NSN was a mixture of dispensable amino acids in which glutamine accounted for 0%, 12.5%, and 100% of total NSN. Leucine oxidation and phenylalanine hydroxylation rates and whole-body leucine and phenylalanine balances were unaffected by addition of supplemental NSN to the diets in phase 1 or by amino acid source of NSN in phase 2. Leucine and phenylalanine balances were lower (P < 0.05) for FAO compared with MIT diets.
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U2 - 10.1093/ajcn/59.6.1347
DO - 10.1093/ajcn/59.6.1347
M3 - Article
C2 - 8198059
AN - SCOPUS:0028360451
VL - 59
SP - 1347
EP - 1355
JO - American Journal of Clinical Nutrition
JF - American Journal of Clinical Nutrition
SN - 0002-9165
IS - 6
ER -