4-Aminobutyraldehyde as a substance convertible in vivo to GABA

[2,3-3H]4-Aminobutyraldehyde ([3H]ABAL) was injected subcutaneously into mice, which were sacrificed at various intervals following injection. [3H] gamma-Aminobutyric acid ([3H]GABA) synthesized in vivo from [3H]ABAL was extracted from the brains, separated, and quantitated. The results showed that in the brain, injected [3HABAL was rapidly transformed into [3H]GABA. [3H]ABAL may penetrate the blood--brain barrier into the central nervous system and then be oxidized to [3H]GABA.