Plasma alpha amino-n-butyric acid to leucine ratio: an empirical biochemical marker of alcoholism.

The plasma ratio of alpha-amino-n-butyric acid to leucine was elevated in ambulatory and hospitalized alcoholics as well as in baboons fed alcohol along with an adequate diet. There was a statistically significant positive correlation between this ratio and the degree of alcoholism assessed by three separate medical and psychological criteria in patients maintained on methadone.