Citrulline is created in the body by one of two pathways, either recycled from arginine (the conversion of arginine into nitric oxide leaves citrulline as a byproduct)[1][2] or produced from the nitrogen (and some carbon) contained in L-glutamine,[3] a process in which the enzyme ornithine transcarbamylase uses both ornithine and carbamoyl phosphate (which requires glutamine) to produce citrulline in enterocytes.[4][5]
It appears that the arginine pathway accounts for about 10% of circulating citrulline and the glutamine pathway accounts for 90%;[1] reducing plasma glutamine levels can reduce plasma citrulline.[6]
References
- ^Curis E, Nicolis I, Moinard C, Osowska S, Zerrouk N, Bénazeth S, Cynober LAlmost all about citrulline in mammalsAmino Acids.(2005 Nov)
- ^Rabier D, Kamoun PMetabolism of citrulline in man.Amino Acids.(1995-Dec)
- ^Tomlinson C, Rafii M, Ball RO, Pencharz PArginine synthesis from enteral glutamine in healthy adults in the fed state.Am J Physiol Endocrinol Metab.(2011-Aug)
- ^van de Poll MC, Ligthart-Melis GC, Boelens PG, Deutz NE, van Leeuwen PA, Dejong CHIntestinal and hepatic metabolism of glutamine and citrulline in humans.J Physiol.(2007-Jun-01)
- ^van de Poll MC, Siroen MP, van Leeuwen PA, Soeters PB, Melis GC, Boelens PG, Deutz NE, Dejong CHInterorgan amino acid exchange in humans: consequences for arginine and citrulline metabolism.Am J Clin Nutr.(2007-Jan)
- ^Rougé C, Des Robert C, Robins A, Le Bacquer O, Volteau C, De La Cochetière MF, Darmaun DManipulation of citrulline availability in humansAm J Physiol Gastrointest Liver Physiol.(2007 Nov)