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Precursors for the synthesis of citrulline in mice fed arginine free diets
Author(s) -
Marini Juan C,
Didelija Inka Cajo,
Castillo Leticia,
Lee Brendan
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.740.26
Subject(s) - citrulline , arginine , ornithine , chemistry , glutamine , medicine , endocrinology , endogeny , biochemistry , amino acid , biology
Dietary arginine (Arg) is the main dietary precursor for citrulline (Cit) synthesis. To test the hypothesis that the contribution of dietary proline (Pro) and glutamine (Gln) increases during the feeding of an Arg free diet, rates of appearance (Ra) and precursor‐intermediate‐product relationships were established by the infusion of tracers in conscious mice. There was no difference in RaCit or RaArg due to the lack of Arg in the diet (152 and 564 μmol•kg −1 • h −1 , resp.); however, Ra ornithine (Orn) was greater in the Arg sufficient diet (332 vs. 180 μmol•kg −1 • h −1 ). There was an increase in the utilization of plasma Orn for the synthesis of Cit (47 vs. 34 μmol•kg −1 • h −1 ) in the Arg free diet. There was no difference in the utilization of plasma Arg between the two diets for Cit synthesis, either through plasma Orn (~26 μmol•kg −1 • h −1 ) or at the site of citrulline synthesis (~13 μmol•kg −1 • h −1 ). The contribution of dietary Pro to the synthesis of Cit was mainly at the site of Cit production rather than through plasma Orn (16.7 and 4.6 μmol•kg −1 • h −1 , resp.). Dietary Gln was utilized only at the site of Cit synthesis (4 μmol•kg −1 • h −1 ). Dietary Gln and Pro increased their contribution to the synthesis of Cit during Arg free feeding, but still remained a minor source, despite the absence of Arg in the diet. Endogenous Arg and Orn are able to support Cit synthesis during Arg free feeding. Support: USDA 2533771314 and NIH KO1 RR24173.