Peripheral aromatic L-amino acids decarboxylase inhibitor in Parkinsonism. I. Effect on O-methylated metabolites of L-dopa-2- 14 C.
The effects of MK-486, an inhibitor of peripheral aromatic L-amino acids decarboxylase, on the urinary metabolites derived from orally administered L-Dopa-2-(14)C were studied in three Parkinsonian patients. Treatment with MK-486 before L-Dopa-2-(14)C markedly reduced radioactivity found in catecholamines fraction by 70-80% during 48 hr, but increased 3-O-methyldopa fraction by threefold, as compared with a nonpretreated base line value. Pretreatment with MK-486 for a period of 1 wk resulted in less inhibition of O-methylated amine and acid metabolite fractions than that measured after a single dose of the inhibitor.
D000368:Aged; D000596:Amino Acids; D001345:Autoradiography; D002247:Carbon Isotopes; D002262:Carboxy-Lyases / Q000037:antagonists & inhibitors*; D002395:Catecholamines / Q000378:metabolism; D004295:Dihydroxyphenylalanine / Q000627:therapeutic use*; D004296:Dopa Decarboxylase / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000188:drug therapy* / Q000378:metabolism; D011422:Propionates / Q000627:therapeutic use*; D013997:Time Factors
D000596:Amino Acids; D002247:Carbon Isotopes; D002395:Catecholamines; D011422:Propionates; D004295:Dihydroxyphenylalanine; D002262:Carboxy-Lyases; D004296:Dopa Decarboxylase