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SOME DYNAMIC ASPECTS OF BRAIN METABOLISM IN RATS GIVEN A PORTOCAVAL ANASTOMOSIS
Author(s) -
CREMER JILL E.,
HEATH D. F.,
TEAL HAZEL M.,
WOODS MARGARET S.,
CAVANAGH J. B.
Publication year - 1975
Publication title -
neuropathology and applied neurobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.538
H-Index - 95
eISSN - 1365-2990
pISSN - 0305-1846
DOI - 10.1111/j.1365-2990.1975.tb00653.x
Subject(s) - glutamine , butyrate , metabolism , glutamate receptor , medicine , endocrinology , biology , amino acid , anastomosis , carbohydrate metabolism , biochemistry , surgery , receptor , fermentation
Some dynamic aspects of brain metabolism in rats given a portocaval anastomosis Three weeks after portocaval shunt, when the only ultrastructural change in the CNS is watery swelling of astrocytes, the chronic hyperammonaemia so induced is associated with an increase of brain glutamine (330%), and a decrease of glutamate (90%) and glucose (63%). The metabolic fate of [2– 14 C] glucose was followed over a time course of 40 min after an intravenous injection. Details are given of a compartmental analysis of metabolic kinetic relationships, particularly of brain glutamate and glutamine. When applied to [2– 14 C]glucose data there was no evidence of an increased rate of glutamine synthesis in the operated rats. The increased labelling of glutamine could be accounted for by a larger pool size with a slower fractional turnover coefficient. In control rats [l‐ 14 C]butyrate conferred label very rapidly on a small fraction of brain glutamine. Analysis showed there was little or no overlap between pools of amino acids labelled by [1– 14 C]butyrate and those labelled by [2– 14 C]glu‐cose. In operated animals there was a marked decrease in the total amount of labelled [l‐ 14 C]butyrate entering the brain. Analysis showed some overlap between labelling of amino acids by [ 14 C]butyrate and [ 14 C]glucose, as well as several other changes. The biochemical differences found are likely to be causally related to the ultrastructural changes in astrocytes and lend support to previous concepts of morphological assignments to metabolic compartments.