title: Excretion of amines and their metabolites by two patients in hepatic coma treated with L-dopa.
abstract: Two patients in hepatic coma were treated with L-dopa. The first patient showed clear clinical improvement, but the second patient did not. Analyses of urinary metabolites indicated that L-dopa was not absorbed by the second patient. There was evidence that L-dopa had the following beneficial effects in the first patient: (1) increased production of urine, which could have been accompanied by increased excretion of toxins; (2) displacement of tyramine from transmitter sites (because increased excretion of p-hydroxyphenylacetic acid, a major metabolite of tyramine, occurred during L-dopa treatment in patient 1); (3) replenishment of dopamine, and to a much lesser extent, norepinephrine, at central or peripheral neuroeffector junctions; and (4) scavenging of methyl groups by L-dopa, because ratio of methylated amines to catecholamines was higher than normal in both comatose patients before L-dopa treatment, and this ratio decreased during L-dopa treatment in patient 1.
mesh_terms: D004298:Dopamine / Q000652:urine; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography; D005260:Female; D006501:Hepatic Encephalopathy / Q000188:drug therapy / Q000378:metabolism*; D006801:Humans; D007980:Levodopa / Q000378:metabolism* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000652:urine; D014554:Urination / Q000187:drug effects
chemical_list: D007980:Levodopa; D004298:Dopamine; D009638:Norepinephrine