Theoretically, alpha-ketoglutarate is a precursor of glutamine, a fact that may be of importance given the key regulatory properties of this amino acid. Although the literature suggests that glutamine synthesis accounts only for a marginal part of the disposal of exogenously supplied alpha-ketoglutarate, administered alpha-ketoglutarate has a potent 'sparing' effect on endogenous glutamine pools. When alpha-ketoglutarate is supplied as an ornithine salt, a synergistic effect of the two parts of the molecule increases the synthesis of glutamine or the 'sparing' of endogenous glutamine pools. In addition, alpha-ketoglutarate in combination with ornithine dramatically increases the synthesis of arginine, proline and polyamines, which also play key roles in metabolic adaptation to trauma. The recent literature suggests that the administration of alpha-ketoglutarate in combination with ornithine improves gut morphology and functions, counteracts trauma-induced dysimmunity and exerts anabolic/anticatabolic actions on protein metabolism.