METABOLISM OF THE ASPARTYL MOIETY OF N-ACETYL-l-ASPARTIC ACID IN THE RAT BRAIN

The metabolism of N-acetyl-l -aspartic acid (NAA) was studied in rat brain. Aspartyl-U-¹⁴C]NAA was metabolized predominantly by deacylation. Studies of NAA biosynthesis from l -U-¹⁴C]aspartic acid have confirmed previous reports that NAA turns over slowly in rat brain. However, intracerebrally-injected N-acetyl-l -U-¹⁴C]asparticacid was rapidly metabolized. Exogenous NAA appears to be taken up rapidly into a small, metabolically-active pool. This pool serves as substrate for a tricarboxylic acid cycle associated with the production of glutamate for the biosynthesis of glutamine. The bulk of the NAA content in brain appears to be relatively inactive metabolically.