title: Effect of chronic drug treatment on intestinal membrane transport of  14 C-L-dopa.
abstract: 1. By the use of the everted jejunal sac it was shown that chronic oral treatment of rats with various drugs can either increase or decrease the mucosal transport of (14)C-L-DOPA or alter its serosal/tissue ratio.2. (14)C-L-DOPA transport was significantly increased in rats that were chronically treated with L-DOPA and diminished in those that were treated with chlorpromazine and phenobarbitone.3. Chronic treatment with amantadine and neomycin did not affect (14)C-L-DOPA intestinal transport, although direct addition of amantadine to the medium, significantly increased (14)C-L-DOPA transport in everted sacs of nontreated rats. Addition of neomycin directly to the medium did not affect (14)C-L-DOPA transport.4. The possible mechanisms of these findings and their clinical significance are discussed.
mesh_terms: D000547:Amantadine / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002247:Carbon Isotopes; D002746:Chlorpromazine / Q000494:pharmacology; D004295:Dihydroxyphenylalanine / Q000378:metabolism* / Q000494:pharmacology; D004347:Drug Interactions; D066298:In Vitro Techniques; D007408:Intestinal Absorption / Q000187:drug effects*; D007583:Jejunum / Q000032:analysis / Q000187:drug effects; D008297:Male; D009355:Neomycin / Q000494:pharmacology; D010634:Phenobarbital / Q000494:pharmacology; D051381:Rats
chemical_list: D002247:Carbon Isotopes; D004295:Dihydroxyphenylalanine; D000547:Amantadine; D009355:Neomycin; D002746:Chlorpromazine; D010634:Phenobarbital