Glutamine supplementation does not improve protein synthesis rate by the jejunal mucosa of the malnourished rat.
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 22%/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.
Tannus
Andrea Ferreira S
AF
Division of Nutrology, School of Medicine of Ribeirão Preto, São Paulo University, 14049-900 Ribeirão Preto, Brazil.
Darmaun
Dominique
D
Ribas
Durval F
DF
Oliveira
José Eduardo D
JE
Marchini
Julio Sergio
JS
D000596:Amino Acids / Q000097:blood; D000818:Animals; D001835:Body Weight / Q000187:drug effects*; D002247:Carbon Isotopes / Q000097:blood; D019587:Dietary Supplements; D004195:Disease Models, Animal; D005973:Glutamine / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D007413:Intestinal Mucosa / Q000378:metabolism*; D007583:Jejunum / Q000166:cytology / Q000187:drug effects; D007930:Leucine / Q000378:metabolism*; D008297:Male; D009584:Nitrogen / Q000652:urine*; D014176:Protein Biosynthesis / Q000187:drug effects*; D011502:Protein-Energy Malnutrition / Q000188:drug therapy* / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D012016:Reference Values
D000596:Amino Acids; D002247:Carbon Isotopes; D005973:Glutamine; D007930:Leucine; D009584:Nitrogen