The inactivation of noradrenaline and isoprenaline in dogs
Open Access
- 19 July 1970
- journal article
- Published by Wiley in British Journal of Pharmacology
- Vol. 39 (3) , 573-584
- https://doi.org/10.1111/j.1476-5381.1970.tb10365.x
Abstract
The removal of infused noradrenaline and isoprenaline from the circulation of the dog has been studied, using the blood‐bathed organ technique. Both catecholamines were removed in peripheral vascular beds; in all organs studied, noradrenaline was removed to a greater degree than isoprenaline. The hind legs removed an average of 60% of the noradrenaline passing through, but only 34% of the isoprenaline. With noradrenaline, the degree of removal decreased as the concentration increased, but with isoprenaline, the degree of removal increased with concentration. After phenoxybenzamine, the proportion of isoprenaline removed was unchanged, whereas that of noradrenaline was decreased. The change in removal with the concentration of noradrenaline was also abolished. The results are consistent with the concept that a small fraction of infused noradrenaline is removed from the circulation by Uptake1 and that this is blocked by phenoxybenzamine. Isoprenaline, and the rest of the noradrenaline, are removed by another process (Uptake2?) followed by intracellular metabolism. This inactivation process is unaffected by phenoxybenzamine in concentrations sufficient to give α‐adrenoceptor blockade. After isoprenaline infusions, a substance sometimes appeared in the circulation which contracted the blood‐bathed organs. The systemic pressure response to vaso‐active hormones is not a reliable indicator of the concentration of hormone in the arterial circulation.Keywords
This publication has 15 references indexed in Scilit:
- Effects of phenoxybenzamine on the uptake and metabolism of noradrenaline in the rat heart and vas deferensBritish Journal of Pharmacology, 1969
- The release and fate of vaso‐active hormones in the circulationBritish Journal of Pharmacology, 1969
- Disappearance of Catecholamines from the CirculationNature, 1968
- Pulmonary extractionof bradykinin and eledoisin.1968
- Half-lives of Peptides and Amines in the CirculationNature, 1967
- ESTIMATION OF CATECHOLAMINES BY BIOLOGICAL ASSAY1966
- RETENTION OF INJECTED CATECHOL AMINES BY THE MOUSEBritish Journal of Pharmacology and Chemotherapy, 1962
- A SENSITIVE METHOD FOR THE ASSAY OF 5‐HYDROXYTRYPTAMINEBritish Journal of Pharmacology and Chemotherapy, 1957
- Elimination of Adrenaline and Noradrenaline from the Circulating BloodNature, 1955
- THE NATURE OF HEPATIC AND SPLENIC SYMPATHINBritish Journal of Pharmacology and Chemotherapy, 1950