Summary
The effects of adrenal cortical hormone and thyroxine on brain glutamic acid, γ-amino
butyric acid (GABA) and glutamine were studied in rats fed on the amino acid imbalanced
diet (8% casein diet supplemented with 0.3% L-threonine). The studies revealed that
the decrease in brain glutamic acid and GABA levels in threonine imbalance was recovered
by hydrocortisone supplementation. The increased level of brain glutamine in threonine
imbalance could not, however, be reversed by hydrocortisone supplementation. Thyroxine
supplementation was found to have no impact on any of the members of glutamic acid
family in the brain of rats receiving the threonine-imbalanced diet.
It was suggested that the decreased levels of brain glutamic acid and GABA in threonine
imbalance were caused by diminished adrenal cortical function and the influence of
adrenal cortical hormone could be suggested to reside at the level of formation of
both glutamic acid and GABA.
Key-Words
Amino Acid Imbalance - Threonine Imbalance - Brain - Glutamic Acid - GABA - Glutamine
- Adrenal Cortical Hormone - Hydrocortisone - Thyroid Hormone - Thyroxine