EFFECTS OF SALICYLATE ON AMINO ACID INCORPORATION INTO PROTEIN

¹ Section on Cerebral Metabolism, Laboratory of Clinical Science, National Institute of Mental Health, National Institutes of Health, U. S. Department of Health, Education and Welfare, Public Health Service, Bethesda, Maryland

Salicylate, like thyroxine, stimulates amino acid incorporation into protein in cell-free rat liver homogenates. The optimal concentration is approximately 3 x 10^-3 M in preparations from euthyroid rats. The maximum effect is moderately lower than that of thyroxine, and equivalent effects are obtained with salicylate concentrations approximately twenty times that of thyroxine. Like the thyroxine effect, the action of salicylate is decreased in liver preparations from thyroidectomized rats. Although the actions of thyroxine and salicylate on this process are similar, there is no significant potentiation of the effects of one by the other. The mechanism of the salicylate effect differs in at least one important respect from that of thyroxine; it is not dependent on the presence of mitochondria and an oxidizable substrate and is observed when these components are replaced by a creatine phosphate-ATP generating system.