Methyl group-donating vitamins elevate 3-O-methyldopa in patients with Parkinson disease.

Thomas Müller, Constanze Jugel, Siegfried Muhlack, Fabian Klostermann

Index: Clin. Neuropharmacol. 36(2) , 52-4, (2013)

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Abstract

Levodopa (LD)/dopa decarboxylase inhibitor application increases 3-O-methyldopa (3-OMD) concentrations in association with methyl group transfers, which demand for the conversion of methionine to homocysteine. This accompanying reaction is partially reversible by methyl group-donating vitamins.The objective of this study was to investigate of the effect of methyl group-donating vitamins on 3-OMD synthesis in LD-treated patients with Parkinson disease.We determined LD, 3-OMD, and homocysteine plasma concentrations in relation to daily LD dosage administered orally or as duodenal infusion with and without vitamins.Orally LD-treated patients with Parkinson disease had a lower LD dose compared with the ones on an LD infusion, but LD, 3-OMD, and homocysteine bioavailability was not different. The same 3-OMD and homocysteine accumulation despite the applied higher LD dosage during the infusion indicates a limited methylation capacity. Higher 3-OMD concentrations occurred during chronic vitamin supplementation, whereas the other parameters did not vary from the ones before vitamin intake.Vitamin supplementation elevated methylation of LD to 3-OMD. We suggest that, to a certain extent, plasma levels of homocysteine may reflect methyl group donation resources, whereas 3-OMD concentrations may mirror methylation capacity.