[Effects of glutamine on antioxidants systems and hepatic detoxification in rats: influence of formulation].
OBJECTIVE
The goal of this study is to assess the effect that supplementing parenteral diets with L-glutamine or with L-alanyl-L-glutamine has on the balance of oxidants/antioxidants in the liver and on detoxification systems mediated by P-450 cytochrome in rats.


METHODS
Central catheters were inserted in the animals (n = 60) and they were randomly assigned to one of the following groups: a control group (C) with oral feeding and I.V. infusion of saline solution, a total parenteral nutrition group without glutamine (TPN without GLN), a parenteral nutrition group with glutamine supplement (TPN GLN), and a total parenteral nutrition group with a supplement of alanine-glutamine dipeptide (20 g/L) (TPN ALA-GLN). The parenteral nutrition provided was all isocaloric and isonitrogenated, and the infusions were administered at a speed of 2 ml/h over 5 days.


RESULTS
In the animals of the group without GLN, the liver concentration of glutathione was reduced while the levels of thiobarbituric acid reaction products (TBARS) increased. Supplementing with either glutamine or alanine-glutamine normalized the levels of glutathione but the TBARS levels only fell in the group with the dipeptide. This effect was parallel to the partial recovery of the antioxidant enzyme activities analyzed. The liver concentrations of P-450 cytochrome, P-450 cytochrome dependent mono-oxygenases and the clearance of antipyrine were not modified by the supplements of glutamine or alanine-glutamine.


CONCLUSIONS
Our data suggest a greater protection by alanine-glutamine supplements against the injury produced by free radicals during TPN and the absence of any effect with either glutamine or alanine-glutamine supplements on the oxidative metabolism of the liver.
Ortiz de Urbina
J J
JJ
Servicio de Farmacia, Hospital de León. jortizu@medynet.com
Jorquera
F
F
Culebras
J
J
Villares
C
C
González-Gallego
J
J
Tuñón
M J
MJ
D000818:Animals; D000975:Antioxidants / Q000502:physiology*; D003577:Cytochrome P-450 Enzyme System / Q000187:drug effects* / Q000502:physiology*; D005973:Glutamine / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects*; D010288:Parenteral Nutrition; D051381:Rats; D017208:Rats, Wistar
D000975:Antioxidants; D005973:Glutamine; D003577:Cytochrome P-450 Enzyme System