Dopamine and adrenaline, but not isoprenaline, are substrates for uptake and metabolism in isolated perfused lungs of rats

Bryan-Lluka L.J. and O'Donnell S.R. (1992) Dopamine and adrenaline, but not isoprenaline, are substrates for uptake and metabolism in isolated perfused lungs of rats. Naunyn-Schmiedeberg's Archives of Pharmacology, 346 1: 20-26. doi:10.1007/BF00167565


Author Bryan-Lluka L.J.
O'Donnell S.R.
Title Dopamine and adrenaline, but not isoprenaline, are substrates for uptake and metabolism in isolated perfused lungs of rats
Journal name Naunyn-Schmiedeberg's Archives of Pharmacology   Check publisher's open access policy
ISSN 1432-1912
Publication date 1992
Sub-type Article (original research)
DOI 10.1007/BF00167565
Volume 346
Issue 1
Start page 20
End page 26
Total pages 7
Subject 3004 Pharmacology
Abstract The uptake and subsequent metabolism by catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO) of dopamine, adrenaline, isoprenaline and noradrenaline in isolated perfused lungs of rats has been examined. In lung preparations in which COMT and MAO were inhibited, the uptake of 3H-labelled dopamine, (−)-adrenaline and (−)-noradrenaline, but not (±)-isoprenaline, was reduced by cocaine (10 or 100 μmol/l) The rank order of the Km values of the amines that were substrates for uptake in the lungs were: dopamine (0.246 μmol/l) < noradrenaline (0.967 μmol/l) < adrenaline (3.32 μmol/l). These results are consistent with transport of catecholamines in rat lungs by Uptake1. In lung preparations with COMT and MAO intact, dopamine and noradrenaline were removed from the circulation (50% and 32%, respectively) and mainly metabolized. There was very little (3.0%) removal of isoprenaline by the lungs and adrenaline was not included in this part of the study. In lung preparations in which only MAO was inhibited, the rank order of COMT activity for O-methylation of the amines was dopamine ≪ noradrenaline ≥ adrenaline (kCOMT values: 4.98 min−1, 0.357 min−1, and 0.234 min−1, respectively). If dopamine or adrenaline are perfused through the pulmonary circulation in isolated lungs of the rat, they are taken up and then metabolized by COMT and MAO, as also occurs for noradrenaline. Isoprenaline is not a substrate for uptake in the lungs. There was less uptake of adrenaline than noradrenaline, indicating that uptake and metabolism in the lungs may not be a significant removal process for adrenaline in the circulation of rats in vivo. The more marked uptake of dopamine (than of noradrenaline) indicates that uptake and metabolism by the lungs, at least in the rat, may play an important role in the removal of dopamine from the circulation in vivo.
Keyword Catechol-O-methyltransferase
Catecholamines
Monoamine oxidase
Rat lungs
Uptake1
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import
 
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