Species-directed variation and non-uniform distribution of glycogen in mammalian brains during starvation, diabetes and anesthesia.
An ordered distribution of glycogen across various areas of rat, guinea pig and mouse brain was found. The cortex contained the lowest concentration of glycogen, intermediate concentrations were found in the cerebellum, medulla oblongata, thalamus, pons and olfactory bulb, and the highest concentration of glycogen was in the hypothalamus. In rat brain glycogen concentration ranged from 0.07 to 0.21 mg/g tissue in different cortical areas to 1.17 +/- 0.07 mg/g in the hypothalamus. The concentration of glycogen in guinea pig and mouse brain was 1.5-3.5 and 1.5-4.3-fold higher than in rat brain, respectively. Starvation and diabetes caused a decrease in glycogen concentration in the thalamus, hypothalamus and medulla oblongata. Glycogen concentration in cortical areas was unchanged in starvation and increased in diabetic animals. The reduced glycogen concentration in thalamus, hypothalamus and medulla of diabetic rats could be corrected by insulin treatment, indicating that glycogen metabolism in these areas is insulin dependent. Pentobarbitone anesthesia caused a marked increase in glycogen concentration in all brain areas in normal and in diabetic rats. The effect of pentobarbitone was related to the depth of anesthesia and was reversed following recovery.
Nahas
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Biology and Biochemistry Department, Faculty of Science, Birzeit University, Occupied West Bank, Via Israel.
Abdul-Ghani
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AS