[Glucose metabolism in different regions of the rat brain under hypokinetic stress influence]

In rats kept under long-time hypokinetic stress influence the glucose metabolism was studied in 7 brain regions. The regional levels of glucose, lactate, glutamate, glutamine, aspartate, gamma-aminobutyrate and the incorporation of 14C from plasma glucose into these metabolites, in glycogen and protein were determined. From the content and activity data the regional glucose flux was approximated guantitatively. Under normal conditions the activity gradient cortex and frontal pole greater than cerebellum greater than thalamus and mesencephalon greater than hypothalamus and pons and medulla is identical with that of the regional blood supply (measured with I131 serum albumin as the blood marker). Within the first days of immobilization a functional hypoxia occurred in all brain regions, and the utilization of cycle amino acids for protein synthesis was strongly diminished. After the first week of stress the capillary volumes of all regions increased, the aerobic glucose metabolism was enhanced (factors 1.3--2.0), and the incorporation of glucose-14C via cycle amino acids into protein was considerably potentiated. The metabolic parameters normalized between the 7th and 14th week of stress. Blood supply and metabolic rate were most increased in the hypothalamus, reaching the value measured for the cerebral cortex in the initial state.