Glutamine is one of the most abundant amino acids and participates in a variety of physiological functions, namely - as a major fuel source for enterocytes, as a substrate for neoglucogenesis in kidney, lymphocytes, and monocytes, a nutrient/substrate in muscle protein metabolism in response to infection, inflammation, and muscle trauma. Studies evaluating the role of glutamine have confirmed it's participation in maintaining mucosal integrity of the gastrointestinal tract following it's administration in patients with major bowel surgery. The role of glutamine as a protective agent in hepatobiliary dysfunction and as a supplement in total parenteral nutrition is well established, particularly, in patients under intensive care.
L-Glutamic acid (L-GA) physiologically exists as glutamate. Glutamate along with glutamine plays a major role in amino acid metabolism and thus in maintaining nitrogen balance in the body. Glutamate is a well-established excitatory neurotransmitter in the central nervous system. There has been convincing evidence on protective activity of L-GA and α-ketoglutarate in vincristine-induced neurotoxicity.
Based on the above information, a large number of studies have been carried out. The findings of recent clinical studies are presented below. Looking at the wide profile of activity, it has been proposed that though L-GA and glutamine were once considered nonessential for health, may now be considered as - 'conditionally essential' amino acids. While complete therapeutic role is yet to be elucidated, it may be anticipated that L-GA and glutamine may prove to be exciting molecules of interest to clinicians. The future research may therefore be directed at confirming the above activities and at investigating their role in other clinical conditions.
