Simultaneous radioenzymatic determination of phenylethylamine, phenylethanolamine, tyramine and octopamine in plasma of patients with hepatic encephalopathy.
A sensitive radioenzymatic assay for the simultaneous determination of phenylethylamine, phenylethanolamine, tyramine and octopamine in plasma samples is reported. After extraction with ethanol, the amines are subjected to enzymatic N-methylation with labelled S-adenosylmethionine, preceded in the case of phenylethylamine and of tyramine, by an enzyme-catalyzed beta-hydroxylation step. The procedure is completed by extraction with toluene containing different amounts of isoamylalcohol, followed by controlled evaporation of the solvent. A generalized and highly significant increase in the concentration of all the four amines was found in plasma samples from patients suffering from hepatic encephalopathy.
D004983:Ethanolamines / Q000097:blood; D006501:Hepatic Encephalopathy / Q000097:blood*; D006801:Humans; D018377:Neurotransmitter Agents / Q000097:blood*; D009655:Octopamine / Q000097:blood; D010627:Phenethylamines / Q000097:blood; D012436:S-Adenosylmethionine / Q000378:metabolism; D014439:Tyramine / Q000097:blood
D004983:Ethanolamines; D018377:Neurotransmitter Agents; D010627:Phenethylamines; D009655:Octopamine; C029261:phenethylamine; C005332:N-phenylethanolamine; D012436:S-Adenosylmethionine; D014439:Tyramine