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The physiological disposition of p-octopamine in man

  • J. H. Hengstmann
  • W. Konen
  • C. Konen
  • M. Eichelbaum
  • H. J. Dengler
Article

Summary

After oral administration of 3H-p-octopamine (8 mg≙300 μCi) more 3H-activity (93% of the dose) is excreted in the urine within 24 h than after intravenous infusion (2 mg≙300 μCi) over 2.5 h (82% of the dose). This proves that p-octopamine is absorbed quantitatively in man. The absorption proceeds rapidly, peak plasma levels are reached between 30 and 60 min.

The only metabolic pathways for p-octopamine are deamination and conjugation. The predominant step is oxidative deamination by monoamine oxidase (MAO) to p-hydroxymandelic acid. This acid represents 2/3 of the urinary 3H-activity after both routes of admistration.

A quantitative difference is seen in the fraction of free p-octopamine which equals the amount of conjugated amine after infusion but is only 1/20 after oral administration. This indicates a higher total clearance after an oral dose which consequently explains the diminished efficacy on blood pressure after this route.

Hydroxylation to catecholamines was not found.

Key words

p-Octopamine Enteral Absorption Metabolism 

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Copyright information

© Springer-Verlag 1974

Authors and Affiliations

  • J. H. Hengstmann
    • 1
  • W. Konen
    • 1
  • C. Konen
    • 1
  • M. Eichelbaum
    • 1
  • H. J. Dengler
    • 1
  1. 1.Medizinische Universitätsklinik Bonn-VenusbergBonnGermany

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