Abstract
A simple and senisitve gas-chromatographic method for the determination of N-acetyl-L-aspartic acid (NA-Asp), N-acetyl-.alpha.-aspartylglutamic acid (NA-Asp-Glu) and .beta.-citryl-L-glutamic acid (.beta.-CG) was developed. The organ, regional and phylogenetic distributions of these compounds were studied. NA-Asp and NA-Asp-Glu were highly concentrated in nervous tissue, and less than 1% of the amounts in the nervous tissues were found in nonnervous organs. These 2 compounds showed a reciprocal relationship in their regional distribution in mature brains, but such a relationship was not evident or was even reversed in immature brains. The 2 compounds also showed different developmental changes in different regions of the brain. Fish [carp, Cyprinus carpio] brain contained a relatively high concentration of NA-Asp, but only a trace amount of NA-Asp-Glu. A 10 times higher concentration of NA-Asp-Glu than NA-Asp was found in frog [Rana nigromacultta] brain. Reptilian [turtle, Clemmys japonica] brain contained similar amounts of each compound. Avian and mammalian brain had NA-Asp at a roughly 10 times higher concentration than NA-Asp-Glu. .beta.-CG occurred at the highest concentration in the immature brain of rat and guinea pig, but disappeared in the mature brains. The adult frog brain contained a large amount of .beta.-CG. In the adult rat, testis contained the highest concentration of .beta.-CG.