Studies on the Metabolism of Arginine and Histidine

THE experiments described in this paper were undertaken in the hope of confirming the suggestion, advanced by Ackroyd and Hopkins [1916], that arginine and histidine are utilised in the animal body as precursors of purines. Not only did Abderhalden and his collaborators [1909, 1910], in testing this very idea, fail to obtain evidence in support of it, but since 1916 the validity of Ackroyd and Hopkins' conclusions has been called in question by several workers. Thus Lewis and Doisy [1918], maintaining normal men on purine- free high-protein diets of high and low content of arginine and histidine, found that no differences in the excretion of purines followed the ingestion of the two types of diet. More recently, Christman and Lewis [1923] have observed a marked diminution in the daily elimination of allantoin following the feeding of amino acids (glycine, alanine and glutaminic acid) to rabbits-results in agreement with those of Abderhalden and Einbeck [1909], who found the excretion of allantoin decreased when histidine was fed to dogs. On the other hand, Harding and Young [1919], feeding placenta (which is rich in arginine and histidine) to young dogs, with a control diet containing an equivalent amount of muscle protein (which is poor in these amino acids) found that the uric acid and allantoin excretions were parallel, and were markedly increased during the placenta feeding.