Abstract
Our aim was to determine the effects of glutamine or alanyl glutamine parenteral supplementation on the liver oxidant/antioxidant balance and on cytochrome P450-mediated detoxication in rats. Animals were infused for 5 days with standard total parenteral nutrition (TPN), glutamine-enriched TPN or alanyl glutamine-enriched TPN. The hepatic concentration of glutathione was reduced and the levels of thiobarbituric acid reactive substances (TBARS) increased in animals receiving standard TPN. Both glutamine and alanyl glutamine supplementation normalized glutathione, but TBARS concentration was only lowered by alanyl glutamine. This effect was parallel to a partial recovery of the activity of antioxidant enzymes. Cytochrome P450 liver content, cytochrome P450-dependent monoxygenases and antipyrine clearance were not modified by glutamine or alanyl glutamine. Our data suggest a better protection against free radicals by alanyl glutamine supplementation and an absence of effects of both glutamine and alanyl glutamine on liver oxidative metabolism.

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