Pyridoxine deficiency was produced in weanling kittens by dietary means. Clinically, the deficient animals showed failure to gain weight, ataxia, and, if left on the diet, seizures and death. In vitro study of isolated cerebral cortex slices from the deficient animals showed decreased formation of γ-aminobutyric acid and decreased oxygen uptake when glucose was the substrate. Addition of pyridoxal phosphate to the incubation media corrected both of these defects toward the levels found in normal littermate controls. The decreased oxygen uptake was also corrected by the addition of γ-aminobutyric acid to the media. It is suggested that in pyridoxine deficiency, cerebral oxidative metabolism is impaired by blockage of the γ-aminobutyric acid ‘shunt’ pathway at the glutamic decarboxylase step. The role of this shunt pathway in normal neuronal metabolism is discussed.
