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Extrarenal citrulline utilization in mice
Author(s) -
Marini Juan C,
Didelija Inka C
Publication year - 2013
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.27.1_supplement.113.8
Subject(s) - arginine , citrulline , chemistry , medicine , kidney , endocrinology , nephrectomy , biochemistry , amino acid
Citrulline (Cit) is an amino acid produced in the gut and used by the kidney, in what is called the intestinal‐renal axis of arginine (Arg) synthesis. However, other sites of Cit utilization may exist given the widespread presence of enzymes needed to carry out this process. To test the hypothesis that the disposal of Cit can take place in extrarenal tissue, studies in chronic (conscious) and acute (anesthetized) nephrectomized mice were conducted. (ureido)[ 15 N]‐citrulline and [ 15 N 4 ] arginine were utilized to determine the rate of Cit appearance (RaCit) and disposal, and the rate of conversion of Cit into Arg (RcCA). Whereas Cit concentration correlated with the extent of kidney ablation (control, 1/2 and 5/6 nephrectomy, 21, 38 and 111 μmol/L, resp.), RaCit remained unchanged (121 μmol•kg −1 •h −1 ). RcCA (108, 75 and 54 μmol•kg −1 •h −1 ) and Cit clearance (103, 56, 30 mL•kg −1 •h −1 ), however, decreased. Acute kidney ligation reduced Cit disposal rate (0.018 vs. 0.031/min, LIG and SHAM resp.) which resulted in a 74% and 93% increase in Cit half life and mean residence time. SHAM resulted in a rapid conversion of Cit into Arg, whereas LIG showed a slow but sustained process, suggesting an extrarenal source for plasma arginine. This source accounted for 25% of the plasma arginine produced. Together these data demonstrate that extrarenal sources for citrulline utilization exist, ant that some of them contribute to plasma arginine.