Glutamine supplementation does not improve protein synthesis rate by the jejunal mucosa of the malnourished rat

Author(s)

Tannus, Anclxea Ferreira S. ^[1] ; Darmaun, Dominique ^{[2, 3]} ; Ribas, Durval F. ^[4] ; Oliveira, Jose Eduardo D. ^[1] ; Marchini, Julio Sergio ^[1]

Affiliation

^[1] Univ Sao Paulo, Sch Med, Div Nutrol, BR-14049900 Ribeirao Preto - Brazil

^[2] Univ Nantes, Nantes - France

^[3] INRA, UMR 1280, F-44026 Nantes - France

^[4] Catanduva Padre Albino Fdn, Sch Med, Dept Med, Div Nutrol, BR-15801150 Catanduva - Brazil

• Document type: Journal article
• Source: Nutrition Research; v. 29, n. 8, p. 596-601, AUG 2009.
• Web of Science Citations: 10

Abstract

It has been demonstrated that glutamine, a conditionally essential amino acid, improves nitrogen balance, acts as a stimulant of protein synthesis, and decreases proteolysis in myopathic children. In contrast, other studies have shown no beneficial effect of glutamine supplementation on burn victims or critically ill patients. Nonetheless, we hypothesized that glutamine supplementation would increase the fractional protein synthesis rate (FSR) in the jejunal mucosa of malnourished male Wistar rats. Thus, the objective of the present study was to test the effect of daily oral glutamine supplementation (0.42 g kg(-1) d(-1) for 14 days) on the FSR of the jejunal mucosa of healthy and malnourished rats. A 4-hour kinetic study with L-{[}1-(13)C]leucine was subsequently performed, and jejunal biopsies were obtained 1.5 cm from the Treitz angle and analyzed. Malnourished rats showed a 25% weight loss and increased urinary nitrogen excretion. Plasma amino acid concentration did not differ between groups. (13)C enrichment in plasma and jejunal cells was higher in the malnourished groups than in the healthy group. The FSR (percent per hour) was similar for the control and experimental groups (P > .05), with a mean range of 220%/h to 27%/h. Oral glutamine supplementation alone did not induce higher protein incorporation by the jejunal mucosa in malnourished rats, regardless of total food intake or the presence or absence of glutamine supplementation. (C) 2009 Elsevier Inc. All rights reserved. (AU)