Harman (1-methyl-beta-carboline) in blood plasma and erythrocytes of nonalcoholics following ethanol loading.

Eleven subjects having no history of substance abuse or dependence who agreed to abstain from alcohol for one week prior to the investigation were selected to participate in the present study. On two occasions, separated by four to six weeks, blood was drawn over an 8-hour period (0, 0.5, 1, 2, 4 and 8 hours). On the first occasion, subjects were given an oral dose of ethanol (1 g/kg) after the first blood sample was drawn (ethanol-loading condition). On the second occasion no ethanol was administered (control condition). On both occasions no detectable harman was found in the plasma of subjects. In the control condition harman was detected in the erythrocytes of 7 subjects which remained relatively stable over time. In the ethanol-loading condition, however, a time-dependent increase of harman in the erythrocytes was observed. The concentration of ethanol, acetaldehyde, and erythrocyte-harman showed a parallel trend over time. These findings demonstrate an increased level of harman following ethanol loading in humans.