The feeding route (enteral or parenteral) affects the plasma response of the dipetide Ala-Gln and the amino acids glutamine, citrulline and arginine, with the administration of Ala-Gln in preoperative patients

Abstract

Enhancement of depressed plasma concentrations of glutamine and arginine is associated with better clinical outcome. Supplementation of glutamine might be a way to provide the patient with glutamine, and also arginine, because glutamine provides the kidney with citrulline, from which the kidney produces arginine when plasma levels of arginine are low. The aim of the present study was to investigate the parenteral and enteral response of the administered dipeptide Ala-Gln, glutamine, citrulline and arginine. Therefore, seven patients received 20 g Ala-Gln, administered over 4 h, parenterally or enterally, on two separate occasions. Arterial blood samples were taken before and during the administration of Ala-Gln. ANOVA and a paired t test were used to test differences (P,0·05). Ala-Gln was undetectable with enteral administration, whereas Ala-Gln remained stable at a plasma concentration of 268 mmol/l throughout parenteral infusion and rapidly decreased towards zero after infusion was stopped. The highest level of glutamine was observed with parenteral infusion of the dipeptide, although enteral infusion also significantly increased plasma levels of glutamine. The highest plasma response of citrulline was observed with the enteral administration of the dipeptide, although parenteral administration also increased plasma levels of citrulline. Plasma arginine increased significantly with parenteral infusion, but not with enteral administration of Ala-Gln. In conclusion, administrations of Ala-Gln, parenteral or enteral, resulted in an increased plasma glutamine response, as compared with baseline. Interestingly, in spite of the high availability of citrulline with enteral administration of the dipeptide, only parenteral infusion of Ala-Gln increased plasma arginine concentration.

Glutamine Supplementation to Critically Ill Patients?

“…Th ese data have also been applied to enteral administration of supplementation, although enteral doses only marginally aff ect plasma concentration [10]- [12]. If the pharmaconutrition philosophy is applied, higher doses are usually given, although the rationale for doses beyond what may be needed to restore a low plasma concentration is purely hypothetical.…”

Metabolic effects of enteral versus parenteral alanyl-glutamine dipeptide administration in critically ill patients receiving enteral feeding: A pilot study

“…Little data are available comparing the metabolic effects of Gln when given by enteral versus parenteral routes (14,26). Also, metabolic results with enteral Gln administration have been inconsistent across studies (27,28).…”

“…There is evidence suggesting that Gln supplementation in PN may be superior to the enteral route in terms of clinical outcomes [11] and repletion of plasma Gln [12]. However, in critically ill patients possessing active intestinal function and receiving EN, whether Gln should be given enterally or parenterally is not clear as data comparing the metabolic effects of intravenous Gln versus enteral Gln in critically ill patients are lacking [14][15]. Therefore, the purposes of this study were to compare metabolic effects of alanyl-Gln given by enteral and parenteral routes versus an unsupplemented control group and to obtain initial data on the potential effects of route of Gln administration.…”

Influence of glutamine on morphological and functional changes of liver in the presence of extrahepatic biliary obstruction in rats

“…Several studies in literature have been evaluating the effects of enteral and parenteral glutamine supplementation. Studies in critically ill patients and surgical patients showed that the parenteral administration was more effective in increasing plasma concentrations in relation to oral administration 16,17 . Another study in mice showed that when L-alanyl-L-glutamine was enterally administrated, there was a more significant increase for the synthesis of L-citrulline and L-arginine in relation to the parenteral administration 18 .…”