[Relationship between blood catecholaminergic variables in depressive patients and normal subjects]

Some biochemical assays are available to test the central NA activity in depressed patients. In several laboratories, two metabolites of NA, namely DHPG and MHPG, in either free, conjugated or total form, have been assayed indifferently for this purpose. The present report shows positive correlations between the level of the two glycols, as well as between their different forms in the plasma. In contrast, the level of erythrocyte COMT activity was not correlated with plasma MHPG, and did not show any change during the treatment with respect to the control pretreatment period in depressed patients. The values of MHPG showed a bimodal distribution in the patients before treatment; the plasma level of this metabolite decreased significantly in the first month of treatment, but did not change subsequently. The COMT activity values, as well as MHPG, were significantly correlated between the different time points, that is the control period and after 1 to 3 months of treatment.