Conversion of glucose to amino acids by brain and liver of the new-born mouse.

In previous studies, 1 day-old mouse brain incubated with uniformly labeled C14-glucose was shown to incorporate significant amounts of radioactivity into the “protein” fraction (1). All of the non-essential amino acids except proline and all of the essential ones except threonine were radioactive and had roughly comparable specific activities (2). The turnover was of such a magnitude as to indicate that 5 to 12 per cent of the protein-bound amino acids were replaced with amino acids derived in part or in whole from glucose (2, 3). Thus, relatively extensive formation of essential amino acids in this system was indicated. The incorporation of uniformly labeled glucose into the protein-bound amino acids of certain other mouse tissues has now been investigated in vitro and in viva in order to determine whether such turnover occurs generally.