Adaptation to a long term (4 weeks) arginine- and precursor (glutamate, proline and aspartate)-free diet.
OBJECTIVE
It is not known whether arginine homeostasis is negatively affected by a "long term" dietary restriction of arginine and its major precursors in healthy adults. To assess the effects of a 4-week arginine- and precursor-free dietary intake on the regulatory mechanisms of arginine homeostasis in healthy subjects.


METHODS
Ten healthy adults received a complete amino acid diet for 1 week (control diet) and following a break period, six subjects received a 4-week arginine, proline, glutamate and aspartate-free diet (APF diet). The other four subjects continued for 4 weeks with the complete diet. On days 4 and 7 of the first week and days 25 and 28 of the 4-week period, the subjects received 24-h infusions of arginine, citrulline, leucine and urea tracers.


RESULTS
During the 4-week APF, plasma arginine fluxes for the fed state, were significantly reduced. There were no significant differences for citrulline, leucine or urea fluxes. Arginine de novo synthesis was not affected by the APF intake. However, arginine oxidation was significantly decreased.


CONCLUSIONS
In healthy adults, homeostasis of arginine under a long term arginine- and precursor-free intake is achieved by decreasing catabolic rates, while de novo arginine synthesis is maintained.
Tharakan
John F
JF
Laboratory of Human Nutrition and Clinical Research Center, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
Yu
Yong M
YM
Zurakowski
David
D
Roth
Rachel M
RM
Young
Vernon R
VR
Castillo
Leticia
L
D000328:Adult; D000704:Analysis of Variance; D001120:Arginine / Q000008:administration & dosage* / Q000172:deficiency / Q000378:metabolism*; D001224:Aspartic Acid / Q000008:administration & dosage / Q000172:deficiency / Q000378:metabolism; D002247:Carbon Isotopes; D002956:Citrulline / Q000378:metabolism; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage; D005260:Female; D018698:Glutamic Acid / Q000008:administration & dosage / Q000172:deficiency / Q000378:metabolism; D006706:Homeostasis; D006801:Humans; D007262:Infusions, Intravenous; D007553:Isotope Labeling / Q000379:methods; D007700:Kinetics; D007930:Leucine / Q000378:metabolism; D008297:Male; D009587:Nitrogen Isotopes; D010084:Oxidation-Reduction; D011392:Proline / Q000008:administration & dosage / Q000172:deficiency / Q000378:metabolism; D013997:Time Factors; D014508:Urea / Q000378:metabolism
D002247:Carbon Isotopes; D004044:Dietary Proteins; D009587:Nitrogen Isotopes; D002956:Citrulline; D001224:Aspartic Acid; D018698:Glutamic Acid; D014508:Urea; D001120:Arginine; D011392:Proline; D007930:Leucine