Prevalence of low monoamine oxidase function in alcoholism.
Several studies have found a trend for low platelet monoamine oxidase activity (MAO) in alcoholism but with a great deal of overlap in MAO activity of alcoholics versus controls. The main objective of this study was to carry out a detailed assessment of MAO function that included the measurement of key kinetic parameters (i.e., Km, Vmax) in three groups of male subjects: (a) 51 hospitalized chronic alcoholics, (b) 16 recovering alcoholics with 2-10 years of abstinence, and (c) 21 controls. MAO activity was assayed radiochemically with [14C]tyramine as substrate (43-729 microM). The present study demonstrated that alcoholics had low platelet MAO activity (p less than 0.05). Kinetic analysis revealed a substantial reduction (p less than 0.01) in enzyme Vmax values of chronic and recovering alcoholics. Greater than 95% of the alcoholics had Vmax values lower than the smallest value of control subjects. Moreover, 100% of the alcoholics in both groups exhibited exceedingly low Vmax values that were below the 25th percentile of controls. In summary, results of MAO Vmax determinations provided us with a better separation of the alcoholics from controls. Measurements of platelet MAO function that include enzyme Vmax may provide us a reliable biochemical marker for alcoholism.
Faraj
B A
BA
Department of Radiology, (Division of Nuclear Medicine), Emory University School of Medicine, Atlanta, GA 30322.
Lenton
J D
JD
Kutner
M
M
Camp
V M
VM
Stammers
T W
TW
Lee
S R
SR
Lolies
P A
PA
Chandora
D
D
D000328:Adult; D000368:Aged; D000437:Alcoholism / Q000201:enzymology* / Q000628:therapy; D001792:Blood Platelets / Q000201:enzymology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008995:Monoamine Oxidase / Q000097:blood*; D014439:Tyramine
D008995:Monoamine Oxidase; D014439:Tyramine