COMPARTMENTATION OF AMINO ACID METABOLISM IN THE RAT POSTERIOR PITUITARY

—Isolated rat posterior pituitary glands were incubated with ¹⁴C]glucose or ¹⁴C]acetate and the incorporation of radioactivity into several amino acids was followed. The results indicated that radioactivity was incorporated from ¹⁴C]glucose into a large pool of glutamate which appeared to be responsible for a large proportion of GABA synthesis in the gland. The specific activity of glutamine was always less than that of glutamate when ¹⁴C]glucose was the precursor employed, whereas ¹⁴C]acetate labelled a glutamate pool which had approximately the same specific activity as that of glutamine. The results are discussed with reference to the compartmentation of amino acid metabolism in the nervous system.