title: Effects of L-dopa on putrescine levels in the brain and the liver of the rat.
abstract: The pharmacological effects of several amino acid precursors of putative neurotransmitters on putrescine levels in the brain and the liver of the rat were studied. L-dopa increased brain and liver putrescine levels in a dose-dependent manner that reached its maximum effect in 4-6 h. The increase in liver putrescine was associated with a concomitant increase in ornithine decarboxylase activity. L-5-hydroxytryptophan increased liver putrescine but had no effect on brain putrescine levels. D-DOPA and D-5-hydroxytryptophan were both ineffective in altering brain or liver putrescine. The effects of L-DOPA persisted after hypophysectomy and were not associated with changes in tissue levels of S-adenosylmethionine. The repeated administration of L-DOPA for periods of 48 and 96 h resulted in a sustained elevation of putrescine levels in the brain but not in the liver.
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects*; D004295:Dihydroxyphenylalanine / Q000494:pharmacology; D007016:Hypophysectomy; D007980:Levodopa / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009955:Ornithine Decarboxylase / Q000378:metabolism; D011700:Putrescine / Q000378:metabolism*; D051381:Rats; D012436:S-Adenosylmethionine / Q000032:analysis; D013095:Spermidine / Q000378:metabolism; D013997:Time Factors
chemical_list: D000596:Amino Acids; D007980:Levodopa; D004295:Dihydroxyphenylalanine; D012436:S-Adenosylmethionine; D009955:Ornithine Decarboxylase; D013095:Spermidine; D011700:Putrescine