Abstract
Pyridoxal-5′-phosphate (PLP) plays a crucial role in regulating the steady-state levels of γ-aminobutyric acid (GABA) in CNS. Adrenalectomy resulted in decreased conversion of dietary vitamin B6 to PLP. As a consequence of this, GABA levels in cerebral cortex decrease, since synthesis of GABA is determined by glutamate decarboxylase, a PLP-dependent enzyme. Feeding diet supplemented with vitamin B6 elevated the GABA levels in adrenalectomized animals, because of increased availability of the coenzyme for apodecarbox-ylase. The data suggest a role for corticosteroids in maintaining GABA levels, through their effects on PLP formation.