title: Effect of major and minor surgery on plasma levels of arginine, citrulline, nitric oxide metabolites, and ornithine in humans.
abstract: OBJECTIVE
  To determine the effect of surgical invasiveness on plasma levels of arginine, citrulline, ornithine, and nitric oxide (NO) in humans.
  
  
  BACKGROUND
  Surgical trauma may have a profound effect on the metabolism of NO. However, human studies reported both increased and decreased NO levels after hemorrhagic shock. Arginine, citrulline, and ornithine are key amino acids involved in NO metabolism, but studies evaluating these amino acids together with NO and during 2 types of surgery are lacking. This study tests the hypothesis that major surgery has a more profound effect on plasma levels of arginine, citrulline, NO, and ornithine than minor surgery.
  
  
  METHODS
  Fifteen patients undergoing minor surgery (vulvectomy) and 13 patients undergoing major surgery (laparotomy) were prospectively followed up for 4 days. Plasma was collected for evaluation of levels of arginine, citrulline, NO, and ornithine.
  
  
  RESULTS
  Throughout the experiment, arginine levels did not significantly differ between experimental groups. Perioperative plasma citrulline levels were significantly lower in the laparotomy group than in the vulvectomy group, whereas both groups showed a decrease in citrulline levels at the end of the operation and 24 hours postoperatively. Roughly the same pattern was seen for plasma NO and ornithine levels. However, ornithine levels in the laparotomy group showed a more drastic decrease at the end of the operation and 24 hours postoperatively than citrulline and NO levels.
  
  
  CONCLUSIONS
  The level of surgical invasiveness has the most profound effect on plasma levels of ornithine. In addition, heavier surgical trauma is paired with lower postoperative levels of citrulline and NO metabolites than lighter surgery. It is suggested that surgical trauma stimulates the laparotomy group to consume significantly more ornithine, possibly for use in wound healing.
authors.affiliation: Departments of *Anesthesiology; and †Psychiatry and Clinical Chemistry, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Jaap W
authors.initials: JW
authors.lastname: Hol
authors.forename: Felix
authors.initials: F
authors.lastname: van Lier
authors.forename: Madelous
authors.initials: M
authors.lastname: Valk
authors.forename: Markus
authors.initials: M
authors.lastname: Klimek
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Stolker
authors.forename: Durk
authors.initials: D
authors.lastname: Fekkes
mesh_terms: D000328:Adult; D001120:Arginine / Q000097:blood*; D002956:Citrulline / Q000097:blood*; D005260:Female; D006801:Humans; D007813:Laparotomy; D008875:Middle Aged; D013511:Minor Surgical Procedures; D009569:Nitric Oxide / Q000097:blood* / Q000378:metabolism; D009952:Ornithine / Q000097:blood*; D011446:Prospective Studies; D014845:Vulvar Diseases / Q000601:surgery*
chemical_list: D002956:Citrulline; D009569:Nitric Oxide; D001120:Arginine; D009952:Ornithine