Transient increase in platelet monoamine oxidase b activity during early abstinence in alcoholics: implications for research.

Some earlier studies have suggested that platelet monoamine oxidase (MAO)-B activity should be determined at time points other than early in the abstinence phase. However, the optimal times for blood sampling have not been precisely defined. We therefore assessed platelet MAO-B activity repeatedly in 13 male alcohol-dependent patients over the 2 months after the end of a period of heavy alcohol intake. Twelve healthy men were used as controls. In the alcohol-dependent patients, platelet MAO-B activity was transiently increased from 2 to 6 weeks after the end of alcohol intake and the values during this time period were not different from those of controls. Platelet MAO-B activity was, however, significantly lower in the alcohol-dependent patients at 1 week and at 2 months after the end of alcohol intake, in comparison to controls. It is concluded that the transient increase in platelet MAO-B activity after the end of alcohol intake in alcohol-dependent patients may conceal a difference from a control group. Therefore, it is suggested that when platelet MAO-B activity is determined, the preferential time point for obtaining those values in alcohol-dependent patients is after 2 months of abstinence.