Urinary noradrenaline and serotonin metabolites in drug-free Parkinson patients and the effect of L-dopa treatment.

3-methoxy-4-hydroxyphenylglycol (MHPG) and 5-hydroxyindoleacetic acid (5-HIAA) as well as homovanillic acid (HVA) and cyclic AMP were estimated in the morning urine of 41 drug-free parkinsonian patients and 25 hospitalized controls. In 29 patients, the estimations were repeated after 2 weeks treatment with L-dopa plus decarboxylase inhibitor. Drug-free patients excreted more MHPG and less 5-HIAA than controls. The difference from controls was significant for MHPG, only for the subgroup of patients with akinesia as the main symptom (P = 0.001) and for 5-HIAA only for the tremor subgroup (P = 0.03). 2 weeks treatment with L-dopa plus decarboxylase inhibitor, increased the MHPG excretion significantly only for the akinesia subgroup, where the pretreatment MHPG values were high, while there was no change in MHPG excretion in the tremor and the rigidity subgroups. The treatment caused no change in the 5-HIAA excretion in the tremor subgroup, where the pretreatment values were low, while in the rigidity and akinesia subgroups 5-HIAA excretion was significantly decreased. These results, as well as our previous results on HVA and cyclic AMP, show that there are considerable differences among the subgroups of parkinsonian patients regarding the metabolism of dopamine, noradrenaline and serotonin.