Lack of correlation between plasma DOPEG and urinary MOPEG levels in depressed patients

Twenty-four-hour urinary excretion of 3-methoxy,4-hydroxyphenylethyleneglycol (MOPEG) and levels of free and conjugated plasma 3,4-dihydroxyphenylethyleneglycol (DOPEG) were measured in 56 depressed patients to find a possible correlation between these two peripheral indices of cerebral noradrenergic activity. Plasma DOPEG was measured at 9:00 AM on the same day that urine was collected for the measurement of MOPEG. All depressed patients were diagnosed as having affective disorders according to DSM-III. No correlation was found between plasma free or conjugated DOPEG levels and urinary MOPEG output. This lack of correlation was found in the total sample of depressed patients (56), in 45 patients diagnosed as having major depressive episodes, and in 24 depressed patients diagnosed as major depressive with melancholia. The authors discuss the significance of this lack of correlation between two peripheral indices of central noradrenergic metabolism.