4-3H]-γ-amino butyric acid was fcrmed from theβ-cyano propionic acid by catalytic reduction in ethanol medium
using tritium gas. β-cyano propionic acid was prepared from glutamic acid by oxidization with chloramine-T. The specific activity of product was 1.51TBq/ mmol
while the radiochemical purity was over 95% by paper chromatography.