ABSTRACT
In psychiatric illness like depression, difference is essential between noradrenergic and serotoninergic sources. Therefore the measurement of urinary excretion of MHPG (3-methoxy-4-hydroxy-phenylethylene-glycol) is interesting, because MHPG seems to be the best reflect of central noradrenergic activity. Analytical assay of MHPG includes an enzymatic hydrolysis and an extraction by ethyl acetate. Separation is conducted by HPLC with fluorometric detection for MHPG and VMA, and electrochemical detection for 5-HIAA, which measurement is simultaneous. Quality control is evaluated (detection limit, linearity, precision, reproducibility, hydrolysis and extraction efficiency). Control values of 15 healthy subjects are 18.9 +/- 8.0 mumol/24 h of total MHPG, 1.5 +/- 1.0 of free MHPG, 8.5 +/- 2.0 of sulfate, and 10.7 +/- 4.4 of glucuronide MHPG (m +/- 2 sigma). In our study on depression, the best biological witness seems to be the sulfate-MHPG: in 16 depressed patients without treatment, its rate is very lowered (1.2 +/- 1.2 mumol/24 h). Total and glucuronide MHPG decrease weaker than sulfate (respectively -51% and -65%), while free MHPG increases (+ 193%) versus controls. Urinary VMA and 5-HIAA, peripheric catabolites of respectively adrenalin and serotonin are not significantly altered. There is no correlation neither between urinary sulfate-MHPG and scale evaluation before treatment, nor between urinary sulfate-MHPG and clinic improvement after antidepressive treatment. At last, the association clomipramine + mianserine shows a clinic improvement faster than clomipramine only, although no significative difference appears in biological markers.
