DETERMINATION OF [C-14] GLUTAMINE SPECIFIC ACTIVITY IN PLASMA

Glutamine is a key amino acid participating in various metabolic pathw ays. Study of the physiology of its carbon skeleton has been hampered by lack of a simple and precise method to measure its [C-14] specific activity in plasma. The present report describes an automated, sensiti ve and specific method to determine plasma [C-14] glutamine specific a ctivity which can be used to measure glutamine carbon turnover and sub strate-product interactions in vivo. An orto-phtalaldehyde derivative is analysed on a reverse phase column by UV detection. With this proce dure mu Mol amounts of glutamine and other plasma compounds can be ass ayed for [C-14] specific activity. The method is sufficiently fast (25 samples in 24 hrs) and reproducible (CV<5.5%) for accurate measuremen ts in a large volume of samples.