In the previous paper dealing with the protein metabolism as well as the structural chemical aspects of the brain proteins in normal cat brain and the brain under chronic compression by means of infusion method, it was reported that organic changes of the brain affect the protein metabolism. This communication briefly describes the results of the experiment conducted by the infusion method on the amino acid metabolism studied with the use of [U-(14)C]-glucose while comparing with the same metabolism in normal cat brain. Further the effect of the functional changes mainly induced by Nembutal on the glucose metabolism in the brain was studied by means of brain perfusion. and this effect was compared with the effect of Nembutal anesthesia as studied by infusion method. The study was also focused on the metabolism of glutamic acid and aspartic acid which are the protein components of crude mitochondrial fractions in the brains of those placed under subacute compression and normal cat brain. After the infusion of [U-(14)C]-glucose, the incorporation of (14)C to free glutamic acid and aspartic acid of the brain was higher in the brain under subacute compression than in normal brain, i.e. the relative specific activity (RSA) was higher in the former than in normal brain. This tendency was more marked in aspartic acid. In observing the glucose metabolism by injecting Nembutal into carotid artery during the brain parfusion, the metabolic pattern at this stage showed a pattern intermediate between that during the high functional state and the low functional state of the brain under perfusion. This resembles the metabolic rates of glutamic acid and aspartic acid of the normal cat brain under a slight anesthesia by the infusion method. Only in the case of aspartic acid the relative specific acitivity (RSA) in the brain during the infusion was considerably lower than RSA during brain perfusion under the influence of Nembutal. In the protein component amino acid metabolism of crude mitochondrial fractions. RSA
of the protein component glutamic acid was higher under subacute compression state than RSA of normal brain.