Brain glutamate and gamma-aminobutyrate (GABA) metabolism in thiamin-deficient rats.
The brain metabolism of glutamate and gamma-aminobutyrate (GABA) was investigated in thiamin-deficient and pair-fed control rats, in order to determine whether the GABA shunt may provide an important alternative to 2-oxo-glutarate dehydrogenase (EC 1.2.4.2) in energy-yielding metabolism in thiamin deficiency. Brains from thiamin-deficient animals contained less glutamate, 2-oxo-glutarate and GABA than those from control animals. The brain content of ATP was unaffected by thiamin deficiency. After intracerebroventricular injection of [14C]glutamate, the specific radioactivity of GABA in the brains from deficient animals was 45-50% higher than that in controls, suggesting a considerable increase in the metabolic flux through the GABA shunt in thiamin deficiency. Brain GABA showed a marked circumannual variation, with a peak in mid-summer and a minimum value in mid-winter.
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Department of Biochemistry, University College and Middlesex School of Medicine, London.
Ankoma-Sey
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Coulson
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Bender
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D000818:Animals; D001921:Brain / Q000378:metabolism*; D005971:Glutamates / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013832:Thiamine Deficiency / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D005971:Glutamates; D005680:gamma-Aminobutyric Acid