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Evidence for saturation of catechol-0-methyltransferase by low concentrations of noradrenaline in perfused lungs of rats

Naunyn-Schmiedeberg's Archives of Pharmacology volume 351, pages 408–416 (1995)Cite this article

Abstract

Previous studies on the pulmonary removal and metabolism of catecholamines in rat lungs have shown that, when the lungs are perfused with a low concentration (1 nmol/1) of noradrenaline, the amine is metabolized by catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO), but is predominantly O-methylated, and the activities of COMT and MAO are 0.357 min–1 and 0.186 min−1, respectively. The aim of the present study was to examine the changes in the metabolic profile of noradrenaline in rat lungs over a range of concentrations, and to examine the kinetics of the pulmonary O-methylation of noradrenaline and adrenaline.

In isolated lungs perfused with 3H-noradrenaline, there was a progressive decrease in the proportion of O-methylated metabolites and a corresponding increase in the proportion of deaminated metabolites, as the noradrenaline concentration in the perfusion solution was increased from 1 to 10 to 100 to 1000 nmol/l. Experiments designed to determine the rate of uptake of noradrenaline in lungs perfused with 1 nmol/l 3H-noradrenaline, under conditions of MAO inhibited, COMT inhibited and COMT and MAO inhibited, showed that the results were compatible with co-existence of COMT and MAO in the pulmonary endothelial cells. Hence, it appeared that the changing metabolic profile with amine concentration in the previous series of experiments was not due to saturation of noradrenaline uptake into cells that contained COMT but not MAO.

Further experiments to examine the kinetics of O-methylation of noradrenaline and adrenaline (MAO inhibited) showed that the O-methylation of these amines in the lungs was predominantly saturable, with half-saturation occurring at concentrations (9.8 nmol/I and 19.4 nmol/l, respectively) that were two orders of magnitude lower than those required to half-saturate uptake1 of the amines. Saturation of O-methylation by these low concentrations of noradrenaline (1) provides the explanation for the change in the metabolic profile of noradrenaline described above and (ii) appears to occur because Vmax uptake ≫ Vmax COMT for the metabolizing system consisting of non-neuronal uptake1 + COMT in the lungs, as has been described previously for the system consisting of uptake2 + COMT in extraneuronal sites in rat heart. The results show that the metabolic profile of catecholamines in the pulmonary circulation will reflect that occurring at physiological levels only if studies are carried out with very low amine concentrations.

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Abbreviations

COMT:

Catechol-O-methyltransferase

DOMA:

3′,4′-dihydroxymandelic acid

DOPEG 3′:

4′-dihydroxyphenylglycol

ECS:

Extracellular space

HSOC:

Half-saturating outside concentration

Km uptake :

Half-saturation constant for uptake

kCOMT :

Rate constant for O-methylation

kMAO :

Rate constant for deamination

kout NA :

Rate constant for efflux of noradrenaline

MAO:

Monoamine oxidase

MB-COMT:

Membrane-bound

COMT:

NMN Normetanephrine

OMDA:

O-methylated deaminated metabolites

S-COMT:

Soluble COMT

T/MNA :

Tissue to medium ratio of noradrenaline

U-0521:

3′,4′-dihydroxy-2-methylpropiophenone

Vmax :

Maximal rate of uptake or O-methylation

Vst-st :

Steady-state rate of metabolite formation

Vuptake :

Rate of uptake

References

  • Ben-Harari RR, Peleg R, Youdim MBH (1982) Rate-limiting step in the metabolism of polar and non-polar monoamines in lung and liver. Br J Pharmacol 78:77–83

    Google Scholar 

  • Bryan LJ (1990) Catechol-O-methyltransferase in pulmonary endothelial cells of rat perfused lungs has a higher activity than monamine oxidase but is saturated at low concentrations of noradrenaline. J Autonom Pharmacol 10:12

    Google Scholar 

  • Bryan LJ, Fleig H, Trendelenburg U (1983) A comparative study of the properties of the catechol-O-methyltransferase inhibitors, U-0521 and tropolone acetamide, in rat perfused heart. Naunyn-Schmiedeberg's Arch Pharmacol 322:6–19

    Google Scholar 

  • Bryan LJ, O'Donnell SR, Trendelenburg U (1984) Kinetics of the O-methylating system for isoprenaline in the trachea and aorta of rabbit. Naunyn-Schmiedeberg's Arch Pharmacol 328:56–61

    Google Scholar 

  • Bryan-Lluka LJ, O'Donnell SR (1992) Dopamine and adrenaline, but not isoprenaline, are substrates for uptake and metabolism in isolated perfused lungs of rats. Naunyn-Schmiedeberg's Arch Pharmacol 346:20–26

    Google Scholar 

  • Bryan-Lluka LJ, Westwood NN, O'Donnell SR (1992) Vascular uptake of catecholamines in perfused lungs of the rat occurs by the same process as Uptake, in noradrenergic neurones. Naunyn-Schmiedeberg's Arch Pharmacol 345:319–326

    Google Scholar 

  • Eisenhofer G, Smolich JJ, Esler MD (1992) Different desipramine-sensitive pulmonary removals of plasma epinephrine and norepinephrine in dogs. Am J Physiol 263:L360-L365

    Google Scholar 

  • Geigy JR (1962) In: Diem K (ed) Documenta Geigy Scientific Tables, 6th edn. Geigy Australia Pty Ltd, Pharmaceuticals Division, Sydney,Australia, pp 54–55 and 160–165

    Google Scholar 

  • Gillis CN, Iwasawa Y (1972) Technique for measurement of norepinephrine and 5-hydroxytryptamine uptake by rabbit lungs. J Appl Physiol 33:404–408

    Google Scholar 

  • Gillis CN, Roth JA (1977) The fate of biogenic monoamines in perfused rabbit lung. Br J Pharmacol 59:585–590

    Google Scholar 

  • Graefe K-H, Stefano FJE, Langer SZ (1973) Preferential metabolism of (−)-3H-norepinephrine through the deaminated glycol in the rat vas deferens. Biochem Pharmacol 22:1147–1160

    Google Scholar 

  • Grohmann M (1987) The activity of the neuronal and extraneuronal catecholamine-metabolizing enzymes of the perfused rat heart. Naunyn-Schmiedeberg's Arch Pharmacol 336:139–147

    Google Scholar 

  • Grohmann M, Trendelenburg U (1984) The substrate specificity of uptake2 in the rat heart. Naunyn-Schmiedeberg's Arch Pharmacol 328:164–173

    Google Scholar 

  • Grohmann M, Trendelenburg U (1985) The handling of five catecholamines by the extraneuronal O-methylating system of the rat heart. Naunyn-Schmiedeberg's Arch Pharmacol 329:264–270

    Google Scholar 

  • Grohmann M, Trendelenburg U (1988) The handling of five amines by the extraneuronal deaminating system of the rat heart. Naunyn-Schmiedeberg's Arch Pharmacol 337:159–163

    Google Scholar 

  • Hughes J, Gillis CN, Bloom FE (1969) The uptake and disposition of dl-norepinephrine in perfused rat lung. J Pharmacol Exp Ther 169:237–248

    Google Scholar 

  • Iwasawa Y, Gillis CN, Aghajanian G (1973) Hypothermic inhibition of 5-hydroxytryptamine and norepinephrine uptake by lung: Cellular location of amines after uptake. J Pharmacol Exp Ther 186:498–507

    Google Scholar 

  • Kurahashi K, Rawlow A, Trendelenburg U (1980) A mathematical model representing the extraneuronal O-methylation system of perfused rat heart. Naunyn-Schmiedeberg's Arch Pharmacol 311:17–32

    Google Scholar 

  • Lundström K, Salminen M, Jalanko A, Savolainen R, Ulmanen I (1991) Cloning and characterization of human placental catechol-O-methyltransferase cDNA. DNA Cell Biol 10: 181–189

    Google Scholar 

  • Nicholas TE, Strum JM, Angelo LS, Junod AF (1974) Site and mechanism of uptake of 3H-1-norepinephrine by isolated perfused rat lungs. Circ Res 35:670–680

    Google Scholar 

  • Rivett AJ, Roth JA (1982) Kinetic studies on the O-methylation of dopamine by human brain membrane-bound catechol O-methyltransferase. Biochem 21:1740–1742

    Google Scholar 

  • Rivett AJ, Eddy BJ, Roth JA (1982) Contribution of sulphate conjugation, deaminatinn, and O-methylation to metabolism of dopamine and norepinephrine in human brain. J Neurochem 39:1009–1016

    Google Scholar 

  • Rivett AJ, Francis A, Roth JA (1983) Distinct cellular localization of membrane-bound and soluble forms of catechol-O-methyltran-sferase in brain. J Neurochem 40:215–219

    Google Scholar 

  • Roth JA (1992) Membrane-bound catechol-O-methyltransferase: a reevaluation of its role in the O-methylation of the catecholamine neurotransmitters. Rev Physiol Biochem Pharmacol 120:1–29

    Google Scholar 

  • Russell WJ, Frewin DB, Jonsson JR (1982) Pulmonary extraction of catecholamines in critically ill patients. Anaesth Intens Care 10:319–323

    Google Scholar 

  • Salminen M, Lundström K, Tilgmann C, Savolainen R, Kalkkinen N, Ulmanen I (1990) Molecular cloning and characterization of rat liver catechol-O-methyltransferase. Gene 93:241–247

    Google Scholar 

  • Snedecor GW, Cochran WG (1989) Statistical methods, 8th edn. Iowa State University Press, Ames, USA

    Google Scholar 

  • Sole MJ, Drobac M, Schwartz L, Hussain MN, Vaughan-Neil EF (1979) The extraction of circulating catecholamines by the lungs in normal man and in patients with pulmonary hypertension. Circulation 60:160–163

    Google Scholar 

  • Trendelenburg U (1984a) The influence of inhibition of catechol-O-methyl transferase or of monoamine oxidase on the extraneuronal metabolism of 3H-(−)-noradrenaline in the rat heart. Naunyn-Schmiedeberg's Arch Pharmacol 327: 285–292

    Google Scholar 

  • Trendelenburg U (1984b) Metabolizing systems. In: Fleming WW, Langer SZ, Graefe K-H, Weiner N (eds) Neuronal and extraneuronal events in autonomic pharmacology. Raven Press, New York, pp 93–109

    Google Scholar 

  • Trendelenburg U, Stefano FJE, Grohmann M (1983) The isotope effect of tritium in 3H-noradrenaline. Naunyn-Schmiedeberg's Arch Pharmacol 323:128–140

    Google Scholar 

  • Westwood NN, Bryan-Lluka LJ (1993) Types A and B monoamine oxidase contribute to the metabolism of norepinephrine in perfused lungs of rats. J Pharmacol Exp Ther 267:815–821

    Google Scholar 

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Affiliations

  1. Department of Physiology and Pharmacology, The University of Queensland, 4072, Brisbane, Queensland, Australia

    Lesley J. Bryan-Lluka

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  1. Lesley J. Bryan-Lluka
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Additional information

Preliminary results of part of this study were presented to the Seventh Meeting on Adrenergic Mechanisms, Porto, Portugal (Bryan 1990)

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Bryan-Lluka, L.J. Evidence for saturation of catechol-0-methyltransferase by low concentrations of noradrenaline in perfused lungs of rats. Naunyn-Schmiedeberg's Arch Pharmacol 351, 408–416 (1995). https://doi.org/10.1007/BF00169082

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  • DOI: https://doi.org/10.1007/BF00169082

Keywords

  • Catechol-O-methyltransferase
  • Monoamine oxidase
  • Noradrenaline
  • Kinetics
  • Rat lungs