Sandler M, Karoum F, Ruthven C R, Calne D B
Science. 1969 Dec 12;166(3911):1417-8. doi: 10.1126/science.166.3911.1417.
The increased excretion of m-hydroxyphenylacetic acid in the urine of patients with parkinsonism being treated with L-dopa was reduced by gut sterilization with neomycin. The p-de-hydroxylation step is thus brought about solely by the action of gut flora; the pathway is unlikely to be involved in the events within the brain leading to the therapeutic benefit effected by L-dopa.
