[In vivo exploration of glutamine metabolism in man]

Glutamine is the most copious aminoacid in the body where it plays fundamental physiological roles. Its is a precursor of hepatic ureagenesis and renal ammoniagenesis; it acts as cellular fuel in tissues with fast turnover (intestine, skin, immune system) and is a potential regulator of protein synthesis. The sites of production (muscle) and utilization of glutamine have been established by multiple catheterization, while 15N-labelled tracers have made it possible to quantify its role as main inter-organ nitrogen carrier, to determine the origin of nitrogen used in its synthesis and to demonstrate in vivo the utilization of glutamine in the human bowel.