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Dietary proline and glutamine contribute to arginine and citrulline synthesis in healthy adult men
Author(s) -
Tomlinson Christopher,
Rafii Mahroukh,
Ball Ronald O.,
Pencharz Paul
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.740.4
Subject(s) - arginine , proline , glutamine , citrulline , ornithine , amino acid , chemistry , biochemistry , medicine , endocrinology , biology
We have previously shown in human neonates and piglets that proline is the sole dietary precursor for arginine synthesis. It is unclear in adult humans whether proline is a dietary precursor for arginine. We performed a multitracer isotope study using 15 N 2 ‐ureido arginine, 15 N proline and 1‐ 13 C glutamine to further elucidate synthesis of citrulline and arginine. Primed, and intermittent infusion of labeled 15 N proline and 1‐ 13 C glutamine were given enterally to 5 healthy men fed a standardized milkshake diet. Blood was sampled at plateau enrichment between 1.5 and 3 hours. Plasma enrichment was seen for all tracers giving flux estimates of 93 μmol/kg/hr for arginine, 154 μmol/kg/hr for proline and 770 μmol/kg/hr for glutamine. Transfer of the label from proline and glutamine to arginine and the intermediaries, ornithine and citrulline, was seen in all subjects. The estimated rate of synthesis of arginine from proline was 3.7 μmol/kg/hr and from glutamine was 8.5 μmol/kg/hr. We have shown that in healthy adult humans, both proline and glutamine contribute significantly in providing the carbon chain for arginine synthesis.