The Effect of Dietary Diammonium Citrate on Glutamine and Glutamic Acid Concentration in the Blood Plasma of Chicks

GLUTAMINE forms a major fraction of the non-protein nitrogen in the blood plasma of humans and other mammals (Hamilton, 1945; Prescott and Waelsch, 1947; Bessman et al., 1948), and it has been suggested that blood glutamine functions as a non-toxic carrier of ammonia (Meister, 1956), and provides the major source of ammonia excreted in the urine (Van Slyke et al., 1943). Recently it has been reported that the blood plasma of the chicken also contains considerable glutamine (Olsen et al., 1962) and it seems likely that in the avian species glutamine plays a particularly important part in ammonia metabolism since it is a major contributor of nitrogen during the synthesis of uric acid (Buchanan and Hartman, 1959). The experiments to be described were designed to provide evidence that the chick uses glutamine as an ammonia carrier in the blood. To this end the response of plasma glutamine to the ingestion…