Decrease in plasma levels of 3,4-dihydroxyphenylethyleneglycol in major depression.

Plasma levels of free and sulfoconjugated 3,4-dihydroxyphenylethyleneglycol (DOPEG), the main deaminated metabolite of norepinephrine, were measured in a group of 45 hospitalized patients presenting a major depression and a group of 45 healthy subjects, matched for sex and age. Compared to healthy subjects, depressed patients had significantly lower plasma levels of free and sulfoconjugated DOPEG. The ratio of free over conjugated DOPEG was not statistically different in the two groups. The reduction of plasma DOPEG levels in the depressed patients did not appear to be related to the duration of drug-free period and was similar in males and females. There was no statistically significant correlation between plasma DOPEG levels and total score on the Hamilton Rating Scale for Depression. Finally, plasma DOPEG levels did not differ in unior bipolar patients. The present data provides further evidence for a reduced CNS noradrenergic transmission in major depression.