The Effect of the Adrenal and Thyroid Glands Upon the Rise of Plasma Amino Acids in the Eviscerated Rat

The mechanism of action of the adrenal cortical hormones upon the nitrogen metabolism has not as yet been elucidated. Previous observations (Engel, Schiller and Pentz, 1949; Bondy, Engel and Farrar, 1949) have suggested that their chief action is probably to promote the breakdown of protein to amino acids, rather than to alter the rate of deamination of amino acids and the formation of urea. Since urea is formed chiefly in the liver, it seemed possible that further information bearing on this point might be obtained by studying the effects of the adrenocortical hormones upon the nitrogen metabolism of the liverless animal. It has also been shown (Rupp, Paschkis and Cantarow, 1949) that the thyroid exerts a protein-catabolic effect under certain circumstances. Previous workers have suggested that this effect may be separate from the effect of the adrenal cortex (White and Dougherty, 1947). An attempt was made to verify this contention in the present experiments.