Evidence for gamma-aminobutyric acid as the inhibitor of gamma-aminobutyric acid binding in the plasma of humans with liver disease and hepatic encephalopathy.

1. Gas-liquid chromatography and a radioreceptor assay were used to measure plasma gamma-aminobutyric acid (GABA) in patients with liver disease and hepatic encephalopathy. 2. There was a significant correlation between the results obtained by the two methods, and compared with controls plasma GABA was elevated. 3. These findings suggest that the increased GABA binding inhibitory activity of plasma of these patients is probably due to GABA itself.